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Is sweeping the floor a good or a service?
[ "a good", "a service" ]
1
closed choice
grade2
social science
economics
Economics
Goods and services
Everything you can buy is either a good or a service. A good is something you can touch or hold in your hands. For example, a hammer is a good. A service is a job you pay someone else to do. For example, cooking food in a restaurant is a service.
To decide whether sweeping the floor is a good or a service, ask these questions: Is sweeping the floor something you can touch? No. Is sweeping the floor a job you might pay someone else to do? Yes. So, sweeping the floor is a service.
What is the capital of Wisconsin?
[ "Annapolis", "Lansing", "Madison", "Green Bay" ]
2
closed choice
grade5
social science
geography
State capitals
Identify state capitals of the Midwest
Madison is the capital of Wisconsin.
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Select the solid.
[ "piece of paper", "rain", "air inside a bubble" ]
0
closed choice
grade2
natural science
physics
States of matter
Identify solids, liquids, and gases
Solid, liquid, and gas are states of matter. Matter is anything that takes up space. Matter can come in different states, or forms. When matter is a solid, it has a shape of its own. Some solids can be bent or broken easily. Others are hard to bend or break. A glass cup is a solid. A sock is also a solid. When matter is a liquid, it takes the shape of its container. Think about pouring a liquid from a cup into a bottle. The shape of the liquid is different in the cup than in the bottle. But the liquid still takes up the same amount of space. Juice is a liquid. Honey is also a liquid. When matter is a gas, it spreads out to fill a space. Many gases are invisible. So, you can’t see them. Air is a gas.
Rain is a liquid. A liquid takes the shape of any container it is in. If you put rainwater into a bucket, the rainwater will take the shape of the bucket. But the rainwater will still take up the same amount of space. The air inside a bubble is a gas. A gas spreads out to fill a space. The air inside a bubble fills all the space in the bubble. If the bubble pops, the air will spread out to fill a much larger space. A piece of paper is a solid. You can fold a piece of paper. But it will still have a size and shape of its own.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnitude of the magnetic force is greater in Pair 2.", "The magnitude of the magnetic force is greater in Pair 1.", "The magnitude of the magnetic force is the same in both pairs." ]
1
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes and shapes.
closed choice
grade8
natural science
physics
Velocity, acceleration, and forces
Compare magnitudes of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is greater when the magnets are larger.
The magnets in Pair 2 attract. The magnets in Pair 1 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force. Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The larger the magnets, the greater the magnitude of the magnetic force between them. Magnet A is the same size in both pairs. But Magnet B is larger in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is greater in Pair 1 than in Pair 2.
What is the name of the colony shown?
[ "Delaware", "Kentucky", "New York", "Vermont" ]
2
closed choice
grade4
social science
us-history
English colonies in North America
Identify the Thirteen Colonies
The colony is New York. During the colonial era, New Hampshire and New York both claimed the territory that would later become the state of Vermont. Vermont was never its own colony.
Which of the following could Emmy's test show?
[ "if the blade guards would break in a crash", "how much the drone weighed with the blade guards", "if adding the blade guards made the drone fly poorly" ]
2
People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. Emmy was designing small aircraft called drones to pick up items from warehouse shelves. She knew that the drones' propeller blades would get damaged if they bumped into anything while flying through the warehouse. So, Emmy wanted to add blade guards to protect the propeller blades. The guards had to be sturdy so they would not break in a crash. But she thought that if the guards weighed too much, the drones would not fly well. So, Emmy put guards made of lightweight metal on one drone. Then she observed how well the drone flew with the guards. Figure: a drone without blade guards.
closed choice
grade7
natural science
science-and-engineering-practices
Engineering practices
Evaluate tests of engineering-design solutions
People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.
Which animal is also adapted for climbing trees?
[ "Grevy's zebra", "bare-eared squirrel monkey" ]
1
s live in rain forests on the island of Sumatra in Asia. They climb trees to find food and shelter. The orangutan's hands and feet are adapted for climbing trees. Figure: Sumatran orangutan.
closed choice
grade3
natural science
biology
Adaptations
Animal adaptations: feet and limbs
An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The shape of an animal's feet is one example of an adaptation. Animals' feet can be adapted in different ways. For example, webbed feet might help an animal swim. Feet with thick fur might help an animal walk on cold, snowy ground.
Look at the picture of the Sumatran orangutan. The Sumatran orangutan has long fingers and toes. It is adapted for climbing trees. The Sumatran orangutan uses its long fingers and toes to hold on to branches while climbing. Now look at each animal. Figure out which animal has a similar adaptation. The bare-eared squirrel monkey has long fingers and toes. It is adapted for climbing trees. The Grevy's zebra has four hoofed feet. It is not adapted for climbing trees. The Grevy's zebra uses its feet to walk and run.
Which animal's limbs are also adapted for climbing trees?
[ "three-toed sloth", "sea turtle" ]
0
Chimpanzees live in the forests of Central Africa. Their limbs are adapted for climbing trees. Figure: chimpanzee.
closed choice
grade4
natural science
biology
Adaptations
Animal adaptations: feet and limbs
An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. Arms, legs, flippers, and wings are different types of limbs. The type of limbs an animal has is an example of an adaptation. Animals' limbs can be adapted in different ways. For example, long legs might help an animal run fast. Flippers might help an animal swim. Wings might help an animal fly.
Look at the picture of the chimpanzee. The chimpanzee uses its long limbs to reach branches while climbing. It uses its fingers and toes to grab the branches. Now look at each animal. Figure out which animal has a similar adaptation. The three-toed sloth has long limbs with fingers and toes. Its limbs are adapted for climbing trees. The sea turtle has flippers. Its limbs are not adapted for climbing trees. The sea turtle uses its flippers to swim underwater.
Which property do these three objects have in common?
[ "translucent", "hard", "soft" ]
1
Select the best answer.
closed choice
grade3
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups.
Look at each object. For each object, decide if it has that property. A hard object does not change shape when pressed or squeezed. All three objects are hard. A translucent object lets light through. But you cannot see clearly through a translucent object. The apple seeds and the canoe are not translucent. A soft object changes shape when pressed or squeezed. None of the objects are soft. The property that all three objects have in common is hard.
Which property do these three objects have in common?
[ "shiny", "rough", "fragile" ]
0
Select the best answer.
closed choice
grade3
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups.
Look at each object. For each object, decide if it has that property. A shiny object reflects a lot of light. You can usually see your reflection in a shiny object. All three objects are shiny. A fragile object will break into pieces if you drop it. The car bumper and the gold ring are not fragile. A rough object feels scratchy when you touch it. The car bumper and the gold ring are not rough. The property that all three objects have in common is shiny.
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What information supports the conclusion that Vivian acquired this trait?
[ "Vivian learned how to play the cello in music class.", "Vivian and her father play the cello together.", "Vivian knows how to polish her cello." ]
0
Read the description of a trait. Vivian can play the cello.
closed choice
grade7
natural science
biology
Genes to traits
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring.
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What is the volume of a watering can?
[ "24 cups", "24 fluid ounces", "24 gallons" ]
0
Select the best estimate.
closed choice
grade5
natural science
units-and-measurement
Units and measurement
Choose customary units of volume
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Volume is a measurement of how much space something takes up. There are many different units of volume. When you are using customary units, volume may be written in units of fluid ounces, cups, or gallons. As the diagram shows, there are 8 fluid ounces in 1 cup and 16 cups in 1 gallon. So, 1 fluid ounce is less than 1 cup and much less than 1 gallon. A glass of milk has a volume of about 8 fluid ounces, or 1 cup. A jug of milk has a volume of 1 gallon.
The best estimate for the volume of a watering can is 24 cups. 24 fluid ounces is too little and 24 gallons is too much.
Which property do these three objects have in common?
[ "sticky", "bouncy", "stretchy" ]
0
Select the best answer.
closed choice
grade3
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups.
Look at each object. For each object, decide if it has that property. A sticky object can attach or stick to other things. All three objects are sticky. A stretchy object gets longer when you pull on it. The ice cream sundae and the ice pop are not stretchy. A bouncy object will bounce back from the floor if you drop it. None of the objects are bouncy. The property that all three objects have in common is sticky.
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Based on this information, what is Remy's phenotype for the fur length trait?
[ "FF", "short fur" ]
1
In a group of Syrian hamsters, some individuals have short fur and others have long fur. In this group, the gene for the fur length trait has two alleles. The allele F is for short fur, and the allele f is for long fur. Remy, a Syrian hamster from this group, has short fur. Remy has two alleles for short fur.
closed choice
grade6
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's phenotype for a trait is its observable version of that trait. Remy's observable version of the fur length trait is short fur. So, Remy's phenotype for the fur length trait is short fur.
Which property do these four objects have in common?
[ "fragile", "transparent", "sweet" ]
0
Select the best answer.
closed choice
grade5
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.
Look at each object. For each object, decide if it has that property. A fragile object will break into pieces if you drop it. All four objects are fragile. You can see clearly through a transparent object. The fish bowl and the glass flask are transparent, but the ceramic tea cup is not. Sugar has a sweet taste. The ceramic tea cup and the icicle are not sweet. The property that all four objects have in common is fragile.
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Which is a sentence fragment?
[ "Devin's favorite season is fall it is cool outside.", "Goes on a big adventure." ]
1
closed choice
grade3
language science
writing-strategies
Sentences, fragments, and run-ons
Is it a complete sentence, a fragment, or a run-on?
A sentence is a group of words that forms a complete thought. It has both a subject and a verb. My friends walk along the path. A sentence fragment is a group of words that does not express a complete thought. It is usually missing a subject or a verb. Knows the answer. This is a sentence fragment. It is missing a subject. Who knows the answer? She knows the answer. The bright red car. This is a sentence fragment. It is missing a verb. What did the bright red car do? The bright red car stopped. A run-on sentence is made up of two sentences that are joined without end punctuation or with just a comma. I knocked on the door it opened. It started raining, we ran inside. To fix a run-on sentence, separate it into two sentences. Add end punctuation after the first sentence, and capitalize the second sentence. I knocked on the door. It opened. It started raining. We ran inside. You can also fix a run-on sentence by rewriting it as a compound sentence. A compound sentence is two sentences joined by a comma and a conjunction such as and, but, or, or so. I knocked on the door, and it opened. It started raining, so we ran inside.
Goes on a big adventure is a sentence fragment. It is missing a subject.
Select the organism in the same species as the Chinese mitten crab.
[ "Melanoplus bivittatus", "Acanthaster planci", "Eriocheir sinensis" ]
2
This organism is a Chinese mitten crab. Its scientific name is Eriocheir sinensis.
closed choice
grade7
natural science
biology
Classification and scientific names
Use scientific names to classify organisms
Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.
A Chinese mitten crab's scientific name is Eriocheir sinensis. Eriocheir sinensis has the same scientific name as a Chinese mitten crab. So, these organisms are in the same species. Acanthaster planci does not have the same scientific name as a Chinese mitten crab. So, Eriocheir sinensis and Acanthaster planci are not in the same species. Melanoplus bivittatus does not have the same scientific name as a Chinese mitten crab. So, Eriocheir sinensis and Melanoplus bivittatus are not in the same species.
Which better describes the tide pool ecosystems in Montaña De Oro State Park?
[ "It has daily flooding and draining of seawater. It also has water that is rich in nutrients.", "It has no sunlight. It also has daily flooding and draining of seawater." ]
0
Figure: Montaña De Oro State Park. Montaña De Oro State Park is in California. The park is on the coast of the Pacific Ocean. It has many tide pool ecosystems.
closed choice
grade3
natural science
biology
Ecosystems
Describe ecosystems
An ecosystem is formed when living and nonliving things interact in an environment. There are many types of ecosystems. Here are some ways in which ecosystems can differ from each other: the pattern of weather, or climate the type of soil or water the organisms that live there
A tide pool is a type of ecosystem. Tide pool ecosystems have the following features: daily flooding and draining of seawater, water that is rich in nutrients, and many different types of organisms. So, the tide pool ecosystems in Montaña De Oro State Park have daily flooding and draining of seawater. They also have water that is rich in nutrients.
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Which text uses the word unique in its traditional sense?
[ "Jon custom ordered his unique coffee table from a master craftsman in Lancaster.", "Jon bought his unique coffee table from a factory outlet store in Lancaster." ]
0
closed choice
grade9
language science
writing-strategies
Word usage and nuance
Explore words with new or contested usages
Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.
The first text uses unique in its traditional sense: being the only one of its kind. Jon custom ordered his unique coffee table from a master craftsman in Lancaster. The second text uses unique in its nontraditional sense: interesting or unusual. Jon's coffee table is an interesting style, but it was made in a factory and is probably not actually one of a kind. Jon bought his unique coffee table from a factory outlet store in Lancaster. Most style guides recommend to use the traditional sense of the word unique because it is considered more standard.
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Using only these supplies, which question can Wanda investigate with an experiment?
[ "Do small rocks or large rocks skip more times when thrown across the river?", "Do round rocks or flat rocks skip more times when thrown across the river?", "Do rocks skip more times when thrown across a river or across a pond?" ]
0
Wanda likes to skip rocks at the river. She notices that some of the rocks she throws skip off the surface of the water many times, while others skip once and then sink. She wonders what factors affect how well rocks skip on the water. So, she decides to design an experiment. She has the following supplies available: 10 small flat rocks 10 large flat rocks access to the river by her school
closed choice
grade7
natural science
science-and-engineering-practices
Designing experiments
Identify questions that can be investigated with a set of materials
Experiments can be designed to answer specific questions. When designing an experiment, you must identify the supplies that are necessary to answer your question. In order to do this, you need to figure out what will be tested and what will be measured during the experiment. Imagine that you are wondering if plants grow to different heights when planted in different types of soil. How might you decide what supplies are necessary to conduct this experiment? First, you need to identify the part of the experiment that will be tested, which is the independent variable. This is usually the part of the experiment that is different or changed. In this case, you would like to know how plants grow in different types of soil. So, you must have different types of soil available. Next, you need to identify the part of the experiment that will be measured or observed, which is the dependent variable. In this experiment, you would like to know if some plants grow taller than others. So, you must be able to compare the plants' heights. To do this, you can observe which plants are taller by looking at them, or you can measure their exact heights with a meterstick. So, if you have different types of soil and can observe or measure the heights of your plants, then you have the supplies you need to investigate your question with an experiment!
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The strength of the magnetic force is the same in both pairs.", "The magnetic force is weaker in Pair 2.", "The magnetic force is weaker in Pair 1." ]
2
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.
closed choice
grade3
natural science
physics
Magnets
Compare strengths of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is weaker when the magnets are farther apart.
Distance affects the strength of the magnetic force. When magnets are farther apart, the magnetic force between them is weaker. The magnets in Pair 1 are farther apart than the magnets in Pair 2. So, the magnetic force is weaker in Pair 1 than in Pair 2.
Which solution has a higher concentration of yellow particles?
[ "Solution A", "neither; their concentrations are the same", "Solution B" ]
0
The diagram below is a model of two solutions. Each yellow ball represents one particle of solute.
closed choice
grade8
natural science
chemistry
Solutions
Compare concentrations of solutions
A solution is made up of two or more substances that are completely mixed. In a solution, solute particles are mixed into a solvent. The solute cannot be separated from the solvent by a filter. For example, if you stir a spoonful of salt into a cup of water, the salt will mix into the water to make a saltwater solution. In this case, the salt is the solute. The water is the solvent. The concentration of a solute in a solution is a measure of the ratio of solute to solvent. Concentration can be described in terms of particles of solute per volume of solvent. concentration = particles of solute / volume of solvent
In Solution A and Solution B, the yellow particles represent the solute. To figure out which solution has a higher concentration of yellow particles, look at both the number of yellow particles and the volume of the solvent in each container. Use the concentration formula to find the number of yellow particles per milliliter. Solution A has more yellow particles per milliliter. So, Solution A has a higher concentration of yellow particles.
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Select the action that doesn't belong.
[ "tell", "say", "announce", "write" ]
3
closed choice
grade3
language science
vocabulary
Categories
Select the words that don't belong
Write doesn't belong. Tell, announce, and say all name ways to speak aloud.
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What does the allusion in this text suggest? With the gutters clogged and water rising in the streets, Christine, who was watching the storm from her window, commented, "We're going to need an ark to get out of here."
[ "Christine wants to protect her possessions.", "Christine thinks the storm will cause major flooding." ]
1
closed choice
grade12
language science
figurative-language
Literary devices
Interpret the figure of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. An allusion is a brief reference to something or someone well known, often from history or literature. "I'd better get home before I turn into a pumpkin!" Lila remarked.
The text uses an allusion, a brief reference to someone or something well known. The allusion to an ark suggests that Christine thinks the storm will cause major flooding. In the Bible, it rains for forty days and forty nights; Noah, his family, and animals of every species survive the great flood in an ark that he builds.
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What information supports the conclusion that Judy inherited this trait?
[ "Judy's parents have red hair. They passed down this trait to Judy.", "Judy and her mother both wear their hair in braids." ]
0
Read the description of a trait. Judy has red hair.
closed choice
grade6
natural science
biology
Genes to traits
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down from biological parents to their offspring through genes. Genes are pieces of hereditary material that contain the instructions that affect inherited traits. Offspring receive their genes, and therefore gain their inherited traits, from their biological parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Parents do not pass acquired traits down to their offspring.
Which solution has a higher concentration of green particles?
[ "Solution B", "neither; their concentrations are the same", "Solution A" ]
2
The diagram below is a model of two solutions. Each green ball represents one particle of solute.
closed choice
grade7
natural science
chemistry
Solutions
Compare concentrations of solutions
A solution is made up of two or more substances that are completely mixed. In a solution, solute particles are mixed into a solvent. The solute cannot be separated from the solvent by a filter. For example, if you stir a spoonful of salt into a cup of water, the salt will mix into the water to make a saltwater solution. In this case, the salt is the solute. The water is the solvent. The concentration of a solute in a solution is a measure of the ratio of solute to solvent. Concentration can be described in terms of particles of solute per volume of solvent. concentration = particles of solute / volume of solvent
In Solution A and Solution B, the green particles represent the solute. To figure out which solution has a higher concentration of green particles, look at both the number of green particles and the volume of the solvent in each container. Use the concentration formula to find the number of green particles per milliliter. Solution A has more green particles per milliliter. So, Solution A has a higher concentration of green particles.
In this food chain, the brown trout is a secondary consumer. Why?
[ "It eats a secondary consumer.", "It eats a primary consumer.", "It eats a producer." ]
1
This diagram shows a food chain from the River Frome, a freshwater ecosystem in England.
closed choice
grade5
natural science
biology
Ecosystems
Identify roles in food chains
Every organism needs food to stay alive. Organisms get their food in different ways. A food chain shows how organisms in an ecosystem get their food. The food chain begins with the producer. A producer can change matter that is not food into food. Many producers use carbon dioxide, water, and sunlight to make sugar. Carbon dioxide and water are not food, but sugar is food for the producer. Consumers eat other organisms. There can be several kinds of consumers in a food chain: A primary consumer eats producers. The word primary tells you that this is the first consumer in a food chain. A secondary consumer eats primary consumers. The word secondary tells you that this is the second consumer in a food chain. A tertiary consumer eats secondary consumers. The word tertiary tells you that this is the third consumer in a food chain. A top consumer is the animal at the top of a food chain. Food chains can have different numbers of organisms. For example, when there are four organisms in the chain, the top consumer is the tertiary consumer. But if there are five organisms in the chain, the top consumer eats the tertiary consumer!
In this food chain, the brown trout is a secondary consumer because it eats a primary consumer. The primary consumer in this food chain is the midge larva.
Which property do these four objects have in common?
[ "sticky", "hard", "stretchy" ]
0
Select the best answer.
closed choice
grade5
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.
Look at each object. For each object, decide if it has that property. A stretchy object gets longer when you pull on it. The bubble gum is stretchy, but the ice pop and the chocolate milkshake are not. A sticky object can attach or stick to other things. All four objects are sticky. A hard object does not change shape when pressed or squeezed. The ice pop is hard, but the cake batter, the chocolate milkshake, and the bubble gum are not. The property that all four objects have in common is sticky.
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Which type of sentence is this? Preston took several incredible panoramic photographs of the sweeping view from the top of Table Mountain.
[ "complex", "compound", "compound-complex", "simple" ]
3
closed choice
grade7
language science
grammar
Phrases and clauses
Is the sentence simple, compound, complex, or compound-complex?
A clause is a group of words that contains both a subject and a predicate. An independent clause is a complete thought that can stand alone as a sentence. A dependent clause (or subordinate clause) is not a complete thought and cannot stand alone as a sentence. the oranges on our tree are ripe The clause can stand alone. It is independent. after we pick up Kevin from work The clause cannot stand alone. It is dependent. A simple sentence is made up of a single independent clause. Ben and I spent all day relaxing by the pool. Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate. In the winter, Ben usually wears his heavy coat. Ben usually wears his heavy coat in the winter. A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so. We saw the flash of lightning, and seconds later we heard a rumble of thunder. A complex sentence is made up of an independent clause and a dependent clause. The dependent clause in a complex sentence usually begins with a subordinating conjunction or relative pronoun. Subordinating conjunctions include after, although, as, because, before, if, since, unless, until, when, and while. Relative pronouns include that, which, who, whom, or whose. If she ever gets the chance, Terri would love to visit the Egyptian pyramids. During his trip to Italy, Tony visited the Trevi Fountain, which is in Rome. A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses. After Samantha left work, she stopped at the bank, and then she went to the gym. Sometimes a dependent clause in a complex or compound-complex sentence can interrupt an independent clause. Orcas that are kept in captivity often have bent dorsal fins.
The sentence is simple. It is a single independent clause. Preston took several incredible panoramic photographs of the sweeping view from the top of Table Mountain.
Which of these states is farthest south?
[ "Wisconsin", "Pennsylvania", "Indiana", "Oklahoma" ]
3
closed choice
grade3
social science
geography
Geography
Read a map: cardinal directions
Maps have four cardinal directions, or main directions. Those directions are north, south, east, and west. A compass rose is a set of arrows that point to the cardinal directions. A compass rose usually shows only the first letter of each cardinal direction. The north arrow points to the North Pole. On most maps, north is at the top of the map.
To find the answer, look at the compass rose. Look at which way the south arrow is pointing. Oklahoma is farthest south.
Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?
[ "sample B", "sample A", "neither; the samples have the same temperature" ]
0
The diagrams below show two pure samples of gas in identical closed, rigid containers. Each colored ball represents one gas particle. Both samples have the same number of particles.
closed choice
grade8
natural science
physics
Particle motion and energy
Identify how particle motion affects temperature and pressure
The temperature of a substance depends on the average kinetic energy of the particles in the substance. The higher the average kinetic energy of the particles, the higher the temperature of the substance. The kinetic energy of a particle is determined by its mass and speed. For a pure substance, the greater the mass of each particle in the substance and the higher the average speed of the particles, the higher their average kinetic energy.
Each particle in sample B has more mass than each particle in sample A. The particles in sample B also have a higher average speed than the particles in sample A. So, the particles in sample B have a higher average kinetic energy than the particles in sample A. Because the particles in sample B have the higher average kinetic energy, sample B must have the higher temperature.
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Read the following excerpt from a student essay. How can the writer best improve his or her grammar and mechanics? When my grandparents first bought a computer, they didn't know how to use the Internet, so I sit down with them and show them the ropes. We go over a few basic terms, and I introduce them to different browsers. I taught them where to find the URL for a website and how to use search boxes. We cover different ways to navigate around a website; for example, I show them how to use a mouse, how to scroll up or down a page using the scroll bar, and how to click on links. Now they are excited to be online.
[ "by using consistent verb tenses", "by correcting misplaced modifiers", "by using commas correctly" ]
0
closed choice
grade11
language science
writing-strategies
Editing and revising
Suggest appropriate revisions
During peer review, you read and respond to a fellow student's writing. While there are many methods and strategies that you can use for reviewing a text, it is generally helpful to frame your suggestions in concrete and constructive ways and to consider the following areas for revision: Ideas and development: Does the writer express a clear idea and develop it with evidence, examples, or analysis? Organization: Does the writer order ideas in a clear, logical way so that they build on one another and are easy to follow? Voice: Does the writer maintain an appropriate voice, such as a formal and objective voice in an academic essay or an engaging and expressive voice in a narrative essay? Sentence fluency: Does the writer use sentences that vary in structure and length to create a sense of rhythm and flow within and between sentences, or does the writing sound choppy, rambling, or repetitive? Word choice: Does the writer use words accurately and precisely to create clear, effective, and engaging writing? Grammar and mechanics: Does the writer follow appropriate conventions, using accurate spelling, punctuation, and grammar to create writing that is correct and easy to read?
The writer could best improve his or her grammar and mechanics by using consistent verb tenses. For example, the writer could use past tense for all verbs but the last one; now indicates that the last sentence should be written in present tense. When my grandparents first bought a computer, they didn't know how to use the Internet, so I sit down with them and show them the ropes. We go over a few basic terms, and I introduce them to different browsers. I taught them where to find the URL for a website and how to use search boxes. We cover different ways to navigate around a website; for example, I show them how to use a mouse, how to scroll up or down a page using the scroll bar, and how to click on links. Now they are excited to be online.
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What information supports the conclusion that Francesca inherited this trait?
[ "Francesca and her father both have dark hair.", "Francesca's parents have dark skin. They passed down this trait to Francesca." ]
1
Read the description of a trait. Francesca has dark skin.
closed choice
grade5
natural science
biology
Traits and heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
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Which word would you find on a dictionary page with the following guide words? equal - everyday
[ "escape", "elevator" ]
0
closed choice
grade3
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since escape is between the guide words equal - everyday, it would be found on that page.
Look at the models of molecules below. Select the elementary substance.
[ "acetaldehyde", "hydrazine", "ozone" ]
2
closed choice
grade6
natural science
chemistry
Atoms and molecules
Identify elementary substances and compounds using models
There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you. A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds. Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element boron is B, and the atomic symbol for the chemical element chlorine is Cl. Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a ball-and-stick model. The ball-and-stick model below represents a molecule of the compound boron trichloride. In a ball-and-stick model, the balls represent atoms, and the sticks represent bonds. Notice that the balls in the model above are not all the same color. Each color represents a different chemical element. The legend shows the color and the atomic symbol for each chemical element in the substance.
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Would you find the word blessing on a dictionary page with the following guide words? billow - brown
[ "no", "yes" ]
1
yes or no
grade7
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since blessing is between the guide words billow - brown, it would be found on that page.
What can Brendan and Isaac trade to each get what they want?
[ "Isaac can trade his broccoli for Brendan's oranges.", "Isaac can trade his almonds for Brendan's tomatoes.", "Brendan can trade his tomatoes for Isaac's broccoli.", "Brendan can trade his tomatoes for Isaac's sandwich." ]
2
Trade happens when people agree to exchange goods and services. People give up something to get something else. Sometimes people barter, or directly exchange one good or service for another. Brendan and Isaac open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Brendan wanted broccoli in his lunch and Isaac was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.
closed choice
grade6
social science
economics
Basic economic principles
Trade and specialization
Brendan wanted broccoli in his lunch and Isaac was hoping for tomatoes. Look at the labeled part of the images. Brendan has tomatoes. Isaac has broccoli. They can trade tomatoes for broccoli to both be happier. Trading other things would not help either person get more items they want.
Will these magnets attract or repel each other?
[ "repel", "attract" ]
0
Two magnets are placed as shown. Hint: Magnets that attract pull together. Magnets that repel push apart.
closed choice
grade2
natural science
physics
Magnets
Identify magnets that attract or repel
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles, called north and south. Here are some examples of magnets. The north pole of each magnet is marked N, and the south pole is marked S. If different poles are closest to each other, the magnets attract. The magnets in the pair below attract. If the same poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Will these magnets attract or repel? To find out, look at which poles are closest to each other. The north pole of one magnet is closest to the north pole of the other magnet. Poles that are the same repel. So, these magnets will repel each other.
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Which statement describes the sailboat's motion?
[ "The sailboat is accelerating.", "The sailboat has a constant velocity." ]
0
A sailboat is speeding up as a gust of wind catches the sail.
closed choice
grade8
natural science
physics
Velocity, acceleration, and forces
Identify whether objects are accelerating
An object's velocity describes its speed and its direction. An object has a constant velocity when neither its speed nor its direction is changing. So, an object has a constant velocity when the object is: moving in a straight line at a constant speed, or remaining motionless. If an object does not have a constant velocity, the object is accelerating. An object is accelerating when either its speed or its direction is changing. So, an object is accelerating when the object is: speeding up, slowing down, or changing direction.
The sailboat is speeding up. So, the sailboat is accelerating.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnitude of the magnetic force is smaller in Pair 1.", "The magnitude of the magnetic force is the same in both pairs.", "The magnitude of the magnetic force is smaller in Pair 2." ]
1
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different shapes.
closed choice
grade5
natural science
physics
Magnets
Compare magnitudes of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other.
Both magnet sizes and distance affect the magnitude of the magnetic force. The sizes of the magnets in Pair 1 are the same as in Pair 2. The distance between the magnets is also the same. So, the magnitude of the magnetic force is the same in both pairs.
Select the organism in the same genus as the great gray owl.
[ "Cyanocitta stelleri", "Strix aluco", "Cyanocitta cristata" ]
1
This organism is a great gray owl. Its scientific name is Strix nebulosa.
closed choice
grade4
natural science
biology
Scientific names
Use scientific names to classify organisms
Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.
A great gray owl's scientific name is Strix nebulosa. The first word of its scientific name is Strix. Cyanocitta stelleri is in the genus Cyanocitta. The first word of its scientific name is Cyanocitta. So, Cyanocitta stelleri and Strix nebulosa are not in the same genus. Strix aluco is in the genus Strix. The first word of its scientific name is Strix. So, Strix aluco and Strix nebulosa are in the same genus. Cyanocitta cristata is in the genus Cyanocitta. The first word of its scientific name is Cyanocitta. So, Cyanocitta cristata and Strix nebulosa are not in the same genus.
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Based on this information, what is this fruit fly's phenotype for the antenna type trait?
[ "Aa", "mutated antennae" ]
1
This passage describes the antenna type trait in fruit flies: In a group of fruit flies, some individuals have mutated antennae and others have normal antennae. In this group, the gene for the antenna type trait has two alleles. The allele A is for mutated antennae, and the allele a is for normal antennae. A certain fruit fly from this group has mutated antennae. This fly has one allele for mutated antennae and one allele for normal antennae.
closed choice
grade8
natural science
biology
Genes to traits
Genetics vocabulary: genotype and phenotype
All organisms have pieces of hereditary material called genes, which are passed from parents to offspring. Genes contain instructions for building the parts of an organism. An organism's genes affect its observable traits, including its appearance, its behavior, and which diseases it may have. Genes may have different alleles, or forms, that can cause different versions of a trait. For example, flower color is a trait in pea plants. The gene for this trait has two possible alleles. Each allele is represented by an uppercase or lowercase letter. The allele F is for purple flowers, and the allele f is for white flowers. Each pea plant has two alleles for the flower color gene—one allele inherited from each parent. An organism's genotype for a gene is its combination of alleles for that gene. So, a pea plant may have a genotype of FF, Ff, or ff for the flower color gene. An organism's phenotype for a trait is its observable version of that trait, which depends on the organism's combination of alleles. A pea plant may have a phenotype of purple flowers or white flowers for the flower color trait.
An organism's phenotype for a trait is its observable version of that trait. The fruit fly's observable version of the antenna type trait is mutated antennae. So, the fly's phenotype for the antenna type trait is mutated antennae.
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What information supports the conclusion that Betty acquired this trait?
[ "Betty learned to identify insects by reading many books about insects.", "Betty likes to look at butterflies and beetles." ]
0
Read the description of a trait. Betty is good at identifying insects.
closed choice
grade5
natural science
biology
Traits and heredity
Inherited and acquired traits: use evidence to support a statement
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment.
Which part of the tomato plant makes the seeds?
[ "the fruit", "the flowers" ]
1
A tomato plant can grow seeds.
closed choice
grade4
natural science
biology
Plants
Describe and construct flowering plant life cycles
Many plants have flowers. These plants can use their flowers to reproduce, or make new plants like themselves. How do plants use their flowers to reproduce? First, the male part of the flower makes pollen, and the female part makes eggs. Animals, wind, or water can move pollen. Pollination is what happens when pollen is moved to the female part of the flower. After pollination, sperm from the pollen can combine with the eggs. This is called fertilization. The fertilized eggs grow into seeds. The fruit grows around the seeds. Later, a seed can fall out of the fruit. It can germinate, or start to grow into a new plant.
Flowers make seeds. After a flower is pollinated, male cells from the pollen combine with eggs. This is called fertilization. The fertilized eggs grow into seeds. The fruit can grow around the seeds. But the fruit does not make seeds. Both the fruit and the seeds grow from parts of the flower.
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Is the following trait inherited or acquired? Jacob is good at cooking.
[ "inherited", "acquired" ]
1
Hint: Cooking well takes practice.
closed choice
grade3
natural science
biology
Heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
People are not born knowing how to cook. Instead, many people learn how to cook. So, cooking is an acquired trait.
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How long is a pen?
[ "19 centimeters", "19 kilometers" ]
0
Select the better estimate.
closed choice
grade3
natural science
units-and-measurement
Units and measurement
Choose metric units of distance
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Imagine being told that a pencil is 16 long. You might be thinking, 16 what? Is the pencil 16 centimeters long? 16 meters? 16 kilometers? The number 16 on its own does not give you much information about the length of the pencil. That is because the units are missing. Now look at the drawing of the pencil and the ruler. The ruler shows that the units are centimeters. So, the length of the pencil is 16 centimeters. There are 100 centimeters in 1 meter. So, 1 centimeter is much shorter than 1 meter. There are 1,000 meters in 1 kilometer. So, 1 meter is much shorter than 1 kilometer.
The better estimate for the length of a pen is 19 centimeters. 19 kilometers is too long.
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What is the volume of a bottle of cough syrup?
[ "10 cups", "10 fluid ounces", "10 gallons" ]
1
Select the best estimate.
closed choice
grade5
natural science
units-and-measurement
Units and measurement
Choose customary units of volume
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Volume is a measurement of how much space something takes up. There are many different units of volume. When you are using customary units, volume may be written in units of fluid ounces, cups, or gallons. As the diagram shows, there are 8 fluid ounces in 1 cup and 16 cups in 1 gallon. So, 1 fluid ounce is less than 1 cup and much less than 1 gallon. A glass of milk has a volume of about 8 fluid ounces, or 1 cup. A jug of milk has a volume of 1 gallon.
The best estimate for the volume of a bottle of cough syrup is 10 fluid ounces. 10 cups and 10 gallons are both too much.
Is Rafflesia arnoldii made up of many cells?
[ "yes", "no" ]
0
This organism is Rafflesia arnoldii. It is a member of the plant kingdom. Rafflesia arnoldii has the largest flowers in the world. A single flower can be three feet wide! R. arnoldii is commonly called a corpse flower because the flower smells like rotting meat.
yes or no
grade4
natural science
biology
Classification
Describe, classify, and compare kingdoms
In the past, scientists classified living organisms into two groups: plants and animals. Over the past 300 years, scientists have discovered many more types of organisms. Today, many scientists classify organisms into six broad groups, called kingdoms. Organisms in each kingdom have specific traits. The table below shows some traits used to describe each kingdom. | Bacteria | Archaea | Protists | Fungi | Animals | Plants How many cells do they have? | one | one | one or many | one or many | many | many Do their cells have a nucleus? | no | no | yes | yes | yes | yes Can their cells make food? | some species can | some species can | some species can | no | no | yes
Rafflesia arnoldii is a plant. Plants are made up of many cells.
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Which figure of speech is used in this text? Mona, I've told you a million times: you need to dry the dishes before you put them away.
[ "hyperbole", "oxymoron" ]
0
closed choice
grade9
language science
figurative-language
Literary devices
Classify figures of speech: euphemism, hyperbole, oxymoron, paradox
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. A euphemism is a polite or indirect expression that is used to de-emphasize an unpleasant topic. The head of Human Resources would never refer to firing people, only to laying them off. Hyperbole is an obvious exaggeration that is not meant to be taken literally. I ate so much that I think I might explode! An oxymoron is a joining of two seemingly contradictory terms. Some reviewers are calling this book a new classic. A paradox is a statement that might at first appear to be contradictory, but that may in fact contain some truth. Always expect the unexpected.
The text uses hyperbole, an obvious exaggeration that is not meant to be taken literally. A million times is an exaggeration, since it is unlikely that Mona has actually been told this a million times.
Which property matches this object?
[ "hard", "soft" ]
1
Select the better answer.
closed choice
grade2
natural science
physics
Materials
Identify properties of an object
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.
Look at the object. Think about each property. A soft object changes shape when you squeeze it. The dress is soft. A hard object keeps its shape when you squeeze it. The dress is not hard.
Which three months have over 200millimeters of precipitation in Singapore?
[ "November, December, and January", "August, September, and October", "May, June, and July" ]
0
Use the graph to answer the question below.
closed choice
grade3
natural science
earth-science
Weather and climate
Use climate data to make predictions
Scientists record climate data from places around the world. Precipitation, or rain and snow, is one type of climate data. A bar graph can be used to show the average amount of precipitation each month. Months with taller bars have more precipitation on average.
To describe the average precipitation trends in Singapore, look at the graph. Choice "Jan" is incorrect. Choice "May" is incorrect. Choice "Jun" is incorrect. Choice "Jul" is incorrect. Choice "Aug" is incorrect. Choice "Sep" is incorrect. Choice "Oct" is incorrect. Choice "Nov" is incorrect. Choice "Dec" is incorrect. November, December, and January each have over 200 millimeters of precipitation.
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Suppose Lauren decides to go as a superhero. Which result would be a cost?
[ "Lauren will save some time and money. She won't have to go out and get a new costume.", "Lauren will give up the chance to wear the costume she is more excited about." ]
1
Lauren is deciding whether to go as a vampire or a superhero to a costume party. She would rather go as a vampire. But she already has a superhero costume.
closed choice
grade4
social science
economics
Basic economic principles
Costs and benefits
Before you decide to do something, it is often helpful to list costs and benefits. Costs are what you give up or spend when you decide to do something. Costs involve giving up things that you want or need. Benefits are what you gain or save when you decide to do something. Benefits involve gaining something that you want or need.
This result is a cost. It involves giving up or spending something that Lauren wants or needs: Lauren will give up the chance to wear the costume she is more excited about.
Which property do these four objects have in common?
[ "flexible", "salty", "smooth" ]
2
Select the best answer.
closed choice
grade5
natural science
physics
Materials
Compare properties of objects
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells. Properties can also tell you how an object will behave when something happens to it. Different objects can have properties in common. You can use these properties to put objects into groups. Grouping objects by their properties is called classification.
Look at each object. For each object, decide if it has that property. A flexible object can be folded or bent without breaking easily. The flower petals are flexible, but the wax candle, the ice hockey rink, and the trombone are not. Potato chips have a salty taste. The trombone is not salty. A smooth object is not scratchy or rough. All four objects are smooth. The property that all four objects have in common is smooth.
Will these magnets attract or repel each other?
[ "attract", "repel" ]
1
Two magnets are placed as shown. Hint: Magnets that attract pull together. Magnets that repel push apart.
closed choice
grade3
natural science
physics
Magnets
Identify magnets that attract or repel
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends. Every magnet has two poles, called north and south. Here are some examples of magnets. The north pole of each magnet is marked N, and the south pole is marked S. If different poles are closest to each other, the magnets attract. The magnets in the pair below attract. If the same poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Will these magnets attract or repel? To find out, look at which poles are closest to each other. The north pole of one magnet is closest to the north pole of the other magnet. Poles that are the same repel. So, these magnets will repel each other.
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Which tense does the sentence use? I tell Jayla my opinions about her music.
[ "past tense", "present tense", "future tense" ]
1
closed choice
grade4
language science
verbs
Verb tense
Is the sentence in the past, present, or future tense?
Present tense verbs tell you about something that is happening now. Most present-tense verbs are regular. They have no ending, or they end in -s or -es. Two verbs are irregular in the present tense, to be and to have. You must remember their forms. Past tense verbs tell you about something that has already happened. Most past-tense verbs are regular. They end in -ed. Some verbs are irregular in the past tense. You must remember their past-tense forms. Future tense verbs tell you about something that is going to happen. All future-tense verbs use the word will. Present | Past | Future walk, walks | walked | will walk go, goes | went | will go
The sentence is in present tense. You can tell because it uses a present-tense verb, tell. The verb tells you about something that is true or happening now.
Identify the question that Preston's experiment can best answer.
[ "Do steel nails take fewer days to rust in water compared to vinegar?", "Do steel nails rust in fewer days when submerged in a large volume of liquid compared to a small volume?" ]
0
The passage below describes an experiment. Read the passage and then follow the instructions below. Preston put one two-inch steel nail into each of six test tubes. He added water to three of the test tubes and vinegar to the other three. In each test tube, he completely covered the nail with the same volume of liquid. Preston checked the nails for rust at the same time every day. He recorded how many days it took each nail to become completely covered in rust. Then, he compared the number of days it took nails to rust in water to the number of days it took nails to rust in vinegar. Figure: a new steel nail on a pile of rusty nails.
closed choice
grade6
natural science
science-and-engineering-practices
Designing experiments
Identify the experimental question
Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?
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Last year, there were seven men's clothing stores on Main Street in Fairview. This year, there are only three. What probably happened to the overall supply of men's shirts in Fairview?
[ "The supply probably went up.", "The supply probably went down." ]
1
closed choice
grade8
social science
economics
Supply and demand
Understand overall supply and demand
Overall supply is the total amount of a good or service that producers make and sell. There are several things that can make overall supply go up or down. The table below shows how changes to these things might affect overall supply. | Resources | Number of producers or suppliers | Expected change in demand Supply goes up | when resources cost less or are easier to get | when there are more producers or suppliers | when demand is expected to go up Supply goes down | when resources cost more or are harder to get | when there are fewer producers or suppliers | when demand is expected to go down Producers are people or companies that make goods or provide services. Suppliers are people or companies that sell goods or services. New inventions or technologies can also help workers produce goods and services more quickly. As a result of these changes, the supply of a good or service will often go up.
When four men's clothing stores closed on Main Street, the number of suppliers went down. There were fewer stores selling men's shirts. So, the supply of men's shirts probably went down.
What is the name of the colony shown?
[ "Massachusetts", "Virginia", "Maryland", "Rhode Island" ]
0
closed choice
grade5
social science
us-history
English colonies in North America
Identify the Thirteen Colonies
The colony is Massachusetts. The Massachusetts Colony included land that would later become the state of Maine. Maine was never its own colony.
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Is the following trait inherited or acquired? Darnel can drive a car.
[ "acquired", "inherited" ]
0
Hint: Driving well takes practice.
closed choice
grade4
natural science
biology
Traits and heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
Humans are not born knowing how to drive a car. Instead, many people learn how to drive when they are older. So, driving is an acquired trait.
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Which word would you find on a dictionary page with the following guide words? whoop - wren
[ "wait", "width" ]
1
closed choice
grade8
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since width is between the guide words whoop - wren, it would be found on that page.
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Select the one substance that is not a mineral.
[ "Muscovite is a pure substance. It is not made by living things.", "A shark's tooth is made by a living thing. It is not a pure substance.", "Chrysotile is a solid. It is a pure substance." ]
1
closed choice
grade4
natural science
earth-science
Rocks and minerals
Identify minerals using properties
Minerals are the building blocks of rocks. A rock can be made of one or more minerals. Minerals and rocks have the following properties: Property | Mineral | Rock It is a solid. | Yes | Yes It is formed in nature. | Yes | Yes It is not made by organisms. | Yes | Yes It is a pure substance. | Yes | No It has a fixed crystal structure. | Yes | No You can use these properties to tell whether a substance is a mineral, a rock, or neither. Look closely at the last three properties: Minerals and rocks are not made by organisms. Organisms make their own body parts. For example, snails and clams make their shells. Because they are made by organisms, body parts cannot be minerals or rocks. Humans are organisms too. So, substances that humans make by hand or in factories are not minerals or rocks. A mineral is a pure substance, but a rock is not. A pure substance is made of only one type of matter. Minerals are pure substances, but rocks are not. Instead, all rocks are mixtures. A mineral has a fixed crystal structure, but a rock does not. The crystal structure of a substance tells you how the atoms or molecules in the substance are arranged. Different types of minerals have different crystal structures, but all minerals have a fixed crystal structure. This means that the atoms and molecules in different pieces of the same type of mineral are always arranged the same way. However, rocks do not have a fixed crystal structure. So, the arrangement of atoms or molecules in different pieces of the same type of rock may be different!
Compare the properties of each substance to the properties of minerals. Select the substance whose properties do not match those of minerals. Muscovite is a mineral. A shark's tooth is made by a living thing. But minerals are not made by living things. A shark's tooth is not a pure substance. But all minerals are pure substances. So, a shark's tooth is not a mineral. Chrysotile is a mineral.
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Which object has less thermal energy?
[ "a 250-gram baked potato at a temperature of 60°C", "a 250-gram baked potato at a temperature of 40°C" ]
1
The objects are identical except for their temperatures.
closed choice
grade3
natural science
physics
Heat and thermal energy
How is temperature related to thermal energy?
All solids, liquids, and gases are made of matter. Matter is made up of tiny particles that are always moving. The energy from the motion of these particles is called thermal energy. Temperature measures how hot or cold matter is. If the particles in matter slow down, the temperature goes down. The matter now has both less thermal energy and a lower temperature.
The two baked potatoes have the same mass but different temperatures. Since the 40°C potato is colder than the 60°C potato, it has less thermal energy.
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Is the following trait inherited or acquired? Ted has a scar on his right knee.
[ "acquired", "inherited" ]
0
Hint: Most scars are caused by accidents during a person's life.
closed choice
grade3
natural science
biology
Heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
Children do not inherit their parent's scars. Instead, scars are caused by the environment. People can get scars after they get hurt. So, having a scar is an acquired trait.
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Which text uses the word nauseous in its traditional sense?
[ "Danielle couldn't tolerate the nauseous odor emanating from the landfill, so she rolled up her car windows as she drove past.", "The odor emanating from the landfill made Danielle so nauseous that she had to roll up the car windows as she drove past." ]
0
closed choice
grade9
language science
writing-strategies
Word usage and nuance
Explore words with new or contested usages
Words change in meaning when speakers begin using them in new ways. For example, the word peruse once only meant to examine in detail, but it's now also commonly used to mean to look through in a casual manner. When a word changes in meaning, its correct usage is often debated. Although a newer sense of the word may be more commonly used, many people consider a word's traditional definition to be the correct usage. Being able to distinguish the different uses of a word can help you use it appropriately for different audiences. Britney perused her notes, carefully preparing for her exam. The traditional usage above is considered more standard. David perused the magazine, absentmindedly flipping through the pages. The nontraditional usage above is now commonly used, but traditional style guides generally advise against it.
The second text uses nauseous in its traditional sense: causing disgust or nausea. Danielle couldn't tolerate the nauseous odor emanating from the landfill, so she rolled up her car windows as she drove past. The first text uses nauseous in its nontraditional sense: feeling disgusted or nauseated. The odor emanating from the landfill made Danielle so nauseous that she had to roll up the car windows as she drove past. Most style guides recommend to use the traditional sense of the word nauseous because it is considered more standard.
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Which logical fallacy is used in the text? Did Dalton vote for Sofia for school president, or does he hate her for some reason?
[ "slippery slope fallacy: the false assumption that a small first step will lead to extreme consequences", "false dichotomy: an argument that presents only two choices when more options exist", "circular reasoning: an argument that supports a claim with the claim itself" ]
1
closed choice
grade9
language science
writing-strategies
Developing and supporting arguments
Classify logical fallacies
A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | an attack against the person making the argument, rather than the argument itself appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a broad claim based on too few observations slippery slope fallacy | the false assumption that a small first step will necessarily lead to extreme consequences straw man | a misrepresentation of an opponent's position that makes it easier to argue against
The text argues that Dalton either voted for Sofia or he hates her. However, Dalton could have voted for someone he considers a better candidate while still liking Sofia. This illustrates a type of logical fallacy known as a false dichotomy.
Select the organism in the same species as the Panamanian golden frog.
[ "Atelopus zeteki", "Hyla japonica", "Bufo guttatus" ]
0
This organism is a Panamanian golden frog. Its scientific name is Atelopus zeteki.
closed choice
grade4
natural science
biology
Scientific names
Use scientific names to classify organisms
Scientists use scientific names to identify organisms. Scientific names are made of two words. The first word in an organism's scientific name tells you the organism's genus. A genus is a group of organisms that share many traits. A genus is made up of one or more species. A species is a group of very similar organisms. The second word in an organism's scientific name tells you its species within its genus. Together, the two parts of an organism's scientific name identify its species. For example Ursus maritimus and Ursus americanus are two species of bears. They are part of the same genus, Ursus. But they are different species within the genus. Ursus maritimus has the species name maritimus. Ursus americanus has the species name americanus. Both bears have small round ears and sharp claws. But Ursus maritimus has white fur and Ursus americanus has black fur.
A Panamanian golden frog's scientific name is Atelopus zeteki. Hyla japonica does not have the same scientific name as a Panamanian golden frog. So, Atelopus zeteki and Hyla japonica are not in the same species. Bufo guttatus does not have the same scientific name as a Panamanian golden frog. So, Atelopus zeteki and Bufo guttatus are not in the same species. Atelopus zeteki has the same scientific name as a Panamanian golden frog. So, these organisms are in the same species.
What is the capital of New Mexico?
[ "Santa Fe", "Columbia", "Albuquerque", "Minneapolis" ]
0
closed choice
grade5
social science
geography
State capitals
Identify the 50 state capitals
Santa Fe is the capital of New Mexico.
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Which logical fallacy is used in the text? How do I know that Samantha is the most intelligent person in our geometry class? I know because she's so smart.
[ "circular reasoning: an argument that supports a claim with the claim itself", "appeal to nature: the assumption that natural things are always good" ]
0
closed choice
grade8
language science
writing-strategies
Developing and supporting arguments
Classify logical fallacies
A strong argument uses valid reasoning and logic in support of a claim. When an argument or claim introduces irrelevant information or misrepresents the issues at hand, it may be committing a logical fallacy. Logical fallacies can hurt a writer's credibility and can lead readers to draw false conclusions. A logical fallacy may present irrelevant information: Fallacy | Description ad hominem | a personal attack meant to discredit one's opponent appeal to nature | an argument that assumes the natural choice is always the best choice bandwagon fallacy | an argument that assumes the popular choice is always the best choice circular reasoning | an argument that supports a claim with the claim itself guilt by association | an unfair negative association with another person or group that is intended to discredit someone or something red herring | the use of a completely unrelated topic in support of a claim A logical fallacy may misrepresent the issues at hand: Fallacy | Description false causation | the assumption that because two things happened together, one caused the other false dichotomy | an argument that presents only two choices when more options exist hasty generalization | a very broad claim based on very little evidence straw man | a misrepresentation of an opponent's position that makes it easier to argue against
The text argues that Samantha is intelligent because she's smart. However, the "evidence" is just a restatement of the claim itself. This illustrates a type of logical fallacy known as circular reasoning.
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Which brick has more thermal energy?
[ "the hotter brick", "the colder brick" ]
0
Two 2-kilogram bricks are identical except for their temperatures.
closed choice
grade5
natural science
physics
Heat and thermal energy
How are temperature and mass related to thermal energy?
Matter is made of tiny particles called atoms. Atoms are always moving. The energy of moving atoms is called thermal energy. The total amount of thermal energy in matter depends on three things: the type of matter, the amount of matter, and how fast the atoms are moving. Temperature measures how hot or cold matter is. If the atoms in matter move faster, the temperature goes up. The matter now has both more thermal energy and a higher temperature. What happens if the amount of matter changes? A 2-kilogram brick at 70°F has twice as much thermal energy as a 1-kilogram brick at 70°F. The two bricks have the same temperature, but the larger brick has twice as many atoms. So, it has twice as much thermal energy.
The two bricks are made of the same material and have the same mass. So, the hotter brick has more thermal energy.
Which of the following could Marcy and Brenda's test show?
[ "if a new batch of concrete was firm enough to use", "if the concrete from each batch took the same amount of time to dry" ]
0
People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. The passage below describes how the engineering-design process was used to test a solution to a problem. Read the passage. Then answer the question below. Marcy and Brenda were making batches of concrete for a construction project. To make the concrete, they mixed together dry cement powder, gravel, and water. Then, they checked if each batch was firm enough using a test called a slump test. They poured some of the fresh concrete into an upside-down metal cone. They left the concrete in the metal cone for 30 seconds. Then, they lifted the cone to see if the concrete stayed in a cone shape or if it collapsed. If the concrete in a batch collapsed, they would know the batch should not be used. Figure: preparing a concrete slump test.
closed choice
grade6
natural science
science-and-engineering-practices
Engineering practices
Evaluate tests of engineering-design solutions
People can use the engineering-design process to develop solutions to problems. One step in the process is testing if a potential solution meets the requirements of the design. How can you determine what a test can show? You need to figure out what was tested and what was measured. Imagine an engineer needs to design a bridge for a windy location. She wants to make sure the bridge will not move too much in high wind. So, she builds a smaller prototype, or model, of a bridge. Then, she exposes the prototype to high winds and measures how much the bridge moves. First, identify what was tested. A test can examine one design, or it may compare multiple prototypes to each other. In the test described above, the engineer tested a prototype of a bridge in high wind. Then, identify what the test measured. One of the criteria for the bridge was that it not move too much in high winds. The test measured how much the prototype bridge moved. Tests can show how well one or more designs meet the criteria. The test described above can show whether the bridge would move too much in high winds.
Complete the statement. Ethane is ().
[ "an elementary substance", "a compound" ]
1
The model below represents a molecule of ethane. Ethane is used to make plastic bags.
closed choice
grade5
natural science
chemistry
Atoms and molecules
Classify elementary substances and compounds using models
All substances are made of one or more chemical elements, or types of atoms. Substances that are made of only one chemical element are elementary substances. Substances that are made of two or more chemical elements bonded together are compounds. Every chemical element is represented by its own symbol. For some elements, the symbol is one capital letter. For other elements, the symbol is one capital letter and one lowercase letter. For example, the symbol for the chemical element boron is B, and the symbol for the chemical element chlorine is Cl. Scientists can use models to represent molecules. A ball-and-stick model of a molecule is shown below. This model represents a molecule of the compound boron trichloride. In a ball-and-stick model, the balls represent atoms, and the sticks represent chemical bonds. Notice how each ball is labeled with a symbol for a chemical element. The ball represents one atom of that element.
Count the number of chemical elements represented in the model. Then, decide if ethane is an elementary substance or a compound. In this model, each ball is labeled with C for carbon or H for hydrogen. So, the model shows you that ethane is made of two chemical elements bonded together. Substances made of two or more chemical elements bonded together are compounds. So, ethane is a compound.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnetic force is stronger in Pair 2.", "The strength of the magnetic force is the same in both pairs.", "The magnetic force is stronger in Pair 1." ]
2
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.
closed choice
grade4
natural science
physics
Magnets
Compare strengths of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The stronger the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the strength of a magnetic force between two magnets by changing the distance between them. The magnetic force is stronger when the magnets are closer together.
Distance affects the strength of the magnetic force. When magnets are closer together, the magnetic force between them is stronger. The magnets in Pair 1 are closer together than the magnets in Pair 2. So, the magnetic force is stronger in Pair 1 than in Pair 2.
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Which figure of speech is used in this text? "There's nothing I love more than skipping lunch," Mr. Kelly told the flight attendant when he learned that no food would be available on his cross-country flight.
[ "personification", "verbal irony" ]
1
closed choice
grade8
language science
figurative-language
Literary devices
Classify figures of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Alliteration is the repetition of sounds at the beginning of nearby words. What a lucky little lady you are! An allusion is a brief reference to something or someone well known, often from history or literature. "I'd better get home before I turn into a pumpkin!" Lila remarked. An idiom is an expression that cannot be understood literally. Its meaning must be learned. The assignment was a piece of cake. A simile uses like or as to compare two things that are not actually alike. The cat's fur was as dark as the night. A metaphor compares two things that are not actually alike without using like or as. The snow formed a blanket over the town. Onomatopoeia involves using a word that expresses a sound. The scrambled eggs hit the floor with a splat. Personification is giving human characteristics to nonhuman things. The trees danced in the wind. A pun involves using a word or phrase in a humorous way that suggests more than one meaning. A great new broom is sweeping the nation. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.
The text uses verbal irony, which involves saying one thing but implying something very different. Nothing I love more shows verbal irony because Mr. Kelly is probably upset that there isn't anything to eat.
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Does this passage describe the weather or the climate? Jackie lives in a town with hot summers and freezing cold winters.
[ "weather", "climate" ]
1
Hint: Weather is what the atmosphere is like at a certain place and time. Climate is the pattern of weather in a certain place.
closed choice
grade3
natural science
earth-science
Weather and climate
What's the difference between weather and climate?
The atmosphere is the layer of air that surrounds Earth. Both weather and climate tell you about the atmosphere. Weather is what the atmosphere is like at a certain place and time. Weather can change quickly. For example, the temperature outside your house might get higher throughout the day. Climate is the pattern of weather in a certain place. For example, summer temperatures in New York are usually higher than winter temperatures.
Read the text carefully. Jackie lives in a town with hot summers and freezing cold winters. This passage tells you about the usual temperatures where Jackie lives. It does not describe what the weather is like on a particular day. So, this passage describes the climate.
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Which sentence states a fact?
[ "Only a fool would travel all the way to China to see rocks.", "The Stone Forest in southern China is a cluster of ancient limestone pillars." ]
1
closed choice
grade5
social science
civics
Social studies skills
Identify facts and opinions
A fact is something that can be proved to be true. Facts can be proved by observing, measuring, or studying information. The flag of the United States has 13 stripes. This is a fact. It can be proved by looking at the flag and counting the number of stripes. An opinion is something that a person believes, thinks, or feels. An opinion cannot be proved true. The flag of the United States is easy to draw. This is an opinion. People may have different opinions about what makes a flag "easy" to draw.
The second sentence states a fact. The Stone Forest in southern China is a cluster of ancient limestone pillars. It can be proved by reading a travel guide about China. The first sentence states an opinion. Only a fool would travel all the way to China to see rocks. Only a fool shows what a person believes, thinks, or feels. Another person might have a different opinion about what is foolish.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnitude of the magnetic force is the same in both pairs.", "The magnitude of the magnetic force is smaller in Pair 2.", "The magnitude of the magnetic force is smaller in Pair 1." ]
2
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.
closed choice
grade7
natural science
physics
Velocity, acceleration, and forces
Compare magnitudes of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is smaller when there is a greater distance between the magnets.
Distance affects the magnitude of the magnetic force. When there is a greater distance between magnets, the magnitude of the magnetic force between them is smaller. There is a greater distance between the magnets in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.
Is the following statement about our solar system true or false? Of the four largest planets, three are made mainly of gas.
[ "true", "false" ]
1
Use the data to answer the question below.
true-or false
grade6
natural science
earth-science
Astronomy
Analyze data to compare properties of planets
A planet's volume tells you the size of the planet. The primary composition of a planet is what the planet is made mainly of. In our solar system, planets are made mainly of rock, gas, or ice.
The table tells you that the four largest planets are Jupiter, Saturn, Uranus, and Neptune. Jupiter and Saturn are made mainly of gas. Uranus and Neptune are made mainly of ice. So, of the four largest planets, two are made mainly of gas.
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Which word would you find on a dictionary page with the following guide words? oar - orphan
[ "ought", "oh" ]
1
closed choice
grade8
language science
reference-skills
Reference skills
Use guide words
Guide words appear on each page of a dictionary. They tell you the first word and last word on the page. The other words on the page come between the guide words in alphabetical order. To put words in alphabetical order, put them in order by their first letters. If the first letters are the same, look at the second letters. If the second letters are the same, look at the third letters, and so on. If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order. For example, be comes before bed.
Put the words in alphabetical order. Since oh is between the guide words oar - orphan, it would be found on that page.
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Which sentence is more formal?
[ "Molly didn't enter student politics until her junior year.", "Molly did not enter student politics until her junior year." ]
1
closed choice
grade5
language science
writing-strategies
Author's purpose and tone
Which sentence is more formal?
Formal writing is used for essays, business letters, and reports. The following types of informal language should be avoided in formal writing: Type | Examples slang | cool, awesome idioms | knock your socks off conversational language | gonna, kinda, yeah abbreviated language | ASAP, FYI overly simple or imprecise language | he got some stuff at the store contractions | can't, won't Contractions are not as informal as the other types, but they should be used sparingly in formal writing. Compare the following sentences. The first is informal. The second is formal. Informal: Yeah, ostriches can't fly, but they're awesome runners. Formal: Though ostriches are flightless, they are remarkably adept runners.
The second sentence is less formal. You can tell because it uses a contraction (didn't). The first sentence does not use a contraction, so it is more formal.
What is the expected ratio of offspring with yellow fruit to offspring with red fruit? Choose the most likely ratio.
[ "0:4", "2:2", "1:3", "4:0", "3:1" ]
3
In a group of tomato plants, some individuals have red fruit and others have yellow fruit. In this group, the gene for the fruit color trait has two alleles. The allele for red fruit (F) is dominant over the allele for yellow fruit (f). This Punnett square shows a cross between two tomato plants.
closed choice
grade8
natural science
biology
Genes to traits
Use Punnett squares to calculate ratios of offspring types
Offspring phenotypes: dominant or recessive? How do you determine an organism's phenotype for a trait? Look at the combination of alleles in the organism's genotype for the gene that affects that trait. Some alleles have types called dominant and recessive. These two types can cause different versions of the trait to appear as the organism's phenotype. If an organism's genotype has at least one dominant allele for a gene, the organism's phenotype will be the dominant allele's version of the gene's trait. If an organism's genotype has only recessive alleles for a gene, the organism's phenotype will be the recessive allele's version of the gene's trait. A Punnett square shows what types of offspring a cross can produce. The expected ratio of offspring types compares how often the cross produces each type of offspring, on average. To write this ratio, count the number of boxes in the Punnett square representing each type. For example, consider the Punnett square below. | F | f F | FF | Ff f | Ff | ff There is 1 box with the genotype FF and 2 boxes with the genotype Ff. So, the expected ratio of offspring with the genotype FF to those with Ff is 1:2.
To determine how many boxes in the Punnett square represent offspring with yellow fruit or red fruit, consider whether each phenotype is the dominant or recessive allele's version of the fruit color trait. The question tells you that the F allele, which is for red fruit, is dominant over the f allele, which is for yellow fruit. Yellow fruit is the recessive allele's version of the fruit color trait. A tomato plant with the recessive version of the fruit color trait must have only recessive alleles for the fruit color gene. So, offspring with yellow fruit must have the genotype ff. All 4 boxes in the Punnett square have the genotype ff. Red fruit is the dominant allele's version of the fruit color trait. A tomato plant with the dominant version of the fruit color trait must have at least one dominant allele for the fruit color gene. So, offspring with red fruit must have the genotype FF or Ff. There are 0 boxes in the Punnett square with the genotype FF or Ff. So, the expected ratio of offspring with yellow fruit to offspring with red fruit is 4:0. This means that, based on the Punnett square, this cross will always produce offspring with yellow fruit. This cross is expected to never produce offspring with red fruit.
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Complete the sentence. A can of soda fizzing over is a ().
[ "chemical change", "physical change" ]
1
closed choice
grade5
natural science
chemistry
Physical and chemical change
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form new molecules. The types of molecules in matter before and after a chemical change are always different. Burning a piece of paper is a chemical change. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then relink and form different molecules. For example, carbon dioxide molecules are created when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. For example, water vaporizing is a physical change. Liquid water and water vapor are made of the same type of matter: water.
A can of soda fizzing over is a physical change. The soda fizzes because the gas trapped inside of it comes out very quickly. But the types of matter the soda and gas are made of do not change.
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Is the following trait inherited or acquired? Emmy is good at knitting hats.
[ "inherited", "acquired" ]
1
Hint: People who can knit had to learn how to do it.
closed choice
grade4
natural science
biology
Traits and heredity
Identify inherited and acquired traits
Organisms, including people, have both inherited and acquired traits. Inherited and acquired traits are gained in different ways. Inherited traits are passed down through families. Children gain these traits from their parents. Inherited traits do not need to be learned. Acquired traits are gained during a person's life. Some acquired traits, such as riding a bicycle, are gained by learning. Other acquired traits, such as scars, are caused by the environment. Children do not inherit their parents' acquired traits.
People are not born knowing how to knit. Instead, many people learn how to knit. Knitting well takes practice. So, knitting well is an acquired trait.
Which property matches this object?
[ "rough", "stretchy" ]
0
Select the better answer.
closed choice
grade2
natural science
physics
Materials
Identify properties of an object
An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.
Look at the object. Think about each property. A stretchy object gets longer when you pull on it. The rock are not stretchy. A rough object feels scratchy when you touch it. The rock are rough.
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Select the living thing.
[ "cave", "roller skate", "kelp", "the Great Sphinx of Giza" ]
2
closed choice
grade4
natural science
biology
Classification
Identify living and nonliving things
All living things are made up of cells. Plants, animals, and some fungi have many cells. Other living things are made up of just one cell. All living things need food and water. Water helps living things break down food and remove waste. Food gives living things energy. They use energy from food to grow and change. All living things sense changes in their environment. Living things might sense changes by seeing, smelling, hearing, or feeling. Living things can respond to the changes they sense.
A cave is not a living thing. A cave may have animals or plants living inside. But a cave does not have all the traits of a living thing. A cave does not need food or water. The Great Sphinx of Giza is not a living thing. The Great Sphinx of Giza is a statue of a mythical sphinx, a creature with a lion's body and a human head. The Great Sphinx does not have all of the traits of a living thing. It does not grow or respond to the world around it. It does not need food or water. Kelp is a living thing. Kelp grows and responds to its environment. It needs food and water. It is made up of many cells. Kelp uses energy from sunlight to make food. Kelp plants have special air pockets that bring their leaves close to the surface. A roller skate is not a living thing. Roller skates do not have all of the traits of living things. They do not grow or respond to their environment. They do not need food or water.
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What do these two changes have in common? a puddle freezing into ice on a cold night mixing sand and water
[ "Both are caused by cooling.", "Both are caused by heating.", "Both are only physical changes.", "Both are chemical changes." ]
2
closed choice
grade8
natural science
chemistry
Chemical reactions
Compare physical and chemical changes
Matter is made of very small particles called atoms. Atoms can be linked together by chemical bonds. When two or more atoms link together, they form a molecule. In a chemical change, the chemical bonds in the molecules break. The atoms then link together to form different molecules. The types of molecules in matter before and after a chemical change are always different. Some chemical changes are caused by heating or cooling. For example, burning a piece of paper is a chemical change caused by heating. As paper burns, paper molecules react with oxygen molecules in the air. This reaction breaks the chemical bonds in the molecules. The atoms then link together in a different way to form different molecules. For example, carbon dioxide molecules are formed when paper burns. In a physical change, chemical bonds do not break. The types of molecules in matter before and after a physical change are always the same. A change of state is a type of physical change. Changes of state can be caused by heating or cooling. For example, water vaporizing is a physical change that can be caused by heating. Liquid water and water vapor are made of the same type of matter: water. The law of conservation of mass says that all physical and chemical changes conserve mass. Conserve means to keep the same. So, the total mass before a physical or chemical change is equal to the total mass after the change.
Step 1: Think about each change. A puddle freezing into ice on a cold night is a change of state. So, it is a physical change. Liquid water freezes and becomes solid, but it is still made of water. A different type of matter is not formed. Mixing sand and water is a physical change. Adding water makes the sand wet. But both the sand and water are still made of the same type of matter as before. Step 2: Look at each answer choice. Both are only physical changes. Both changes are physical changes. No new matter is created. Both are chemical changes. Both changes are physical changes. They are not chemical changes. Both are caused by heating. Neither change is caused by heating. Both are caused by cooling. A puddle freezing is caused by cooling. But mixing sand and water is not.
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What is the source of the allusion in the sentence below? Logan's recent behavior made his parents begin to see his friend Ted as some sort of Svengali.
[ "literature", "modern history" ]
0
closed choice
grade12
language science
figurative-language
Literary devices
Recall the source of an allusion
An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. The protean nature of the disease makes it difficult to diagnose. The word protean is an allusion to the sea god Proteus in Greek mythology. Because the sea is constantly changing, to describe something as protean suggests that it is variable or in flux.
The source of the allusion Svengali is literature. In George du Maurier's novel Trilby, Svengali is a hypnotist who exerts such power over the central character that she is suddenly able to sing, which she was unable to do before. The allusion Svengali means a person with an unduly strong influence over someone else.
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Which kind of place usually has less traffic?
[ "a rural area", "an urban area" ]
0
closed choice
grade2
social science
geography
Geography
Compare urban, suburban, and rural areas
People around the world live in three main kinds of places: urban areas, suburban areas, and rural areas. An urban area is a city. It has many people and businesses. The buildings are close to each other. The buildings are often tall and have many floors. Since there are so many people, traffic is usually bad. People will walk or take the bus, train, or subway to avoid traffic. A suburban area, or suburb, is near a city. It is quieter and less crowded than an urban area. People usually live in houses with yards. Most people drive to get places. A rural area is less crowded than both urban and suburban areas. Houses are much more spread out. People usually have to drive to get places. People in rural areas often live on farms or ranches. Some places, like small towns, don't really fit into any of the types. A small town does not have as many people as an urban area, but it has more people than a rural area. It is not near a city, so it is not called a suburb.
Rural areas have much less traffic. There aren't as many people or cars in rural areas.
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What does the verbal irony in this text suggest? According to Mr. Burton's kids, his snoring is as quiet as a jackhammer.
[ "The snoring is loud.", "The snoring occurs in bursts." ]
0
closed choice
grade8
language science
figurative-language
Literary devices
Interpret figures of speech
Figures of speech are words or phrases that use language in a nonliteral or unusual way. They can make writing more expressive. Verbal irony involves saying one thing but implying something very different. People often use verbal irony when they are being sarcastic. Olivia seems thrilled that her car keeps breaking down. Each breakdown is as enjoyable as a punch to the face.
The text uses verbal irony, which involves saying one thing but implying something very different. As quiet as a jackhammer suggests that the snoring is loud. A jackhammer is not quiet, and neither is Mr. Burton's snoring.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnitude of the magnetic force is smaller in Pair 1.", "The magnitude of the magnetic force is smaller in Pair 2.", "The magnitude of the magnetic force is the same in both pairs." ]
1
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material.
closed choice
grade6
natural science
physics
Velocity, acceleration, and forces
Compare magnitudes of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by changing the distance between them. The magnitude of the magnetic force is smaller when there is a greater distance between the magnets.
The magnets in Pair 1 attract. The magnets in Pair 2 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force. Distance affects the magnitude of the magnetic force. When there is a greater distance between magnets, the magnitude of the magnetic force between them is smaller. There is a greater distance between the magnets in Pair 2 than in Pair 1. So, the magnitude of the magnetic force is smaller in Pair 2 than in Pair 1.
Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
[ "The magnitude of the magnetic force is smaller in Pair 2.", "The magnitude of the magnetic force is smaller in Pair 1.", "The magnitude of the magnetic force is the same in both pairs." ]
1
The images below show two pairs of magnets. The magnets in different pairs do not affect each other. All the magnets shown are made of the same material, but some of them are different sizes.
closed choice
grade7
natural science
physics
Velocity, acceleration, and forces
Compare magnitudes of magnetic forces
Magnets can pull or push on each other without touching. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes between magnets are called magnetic forces. The strength of a force is called its magnitude. The greater the magnitude of the magnetic force between two magnets, the more strongly the magnets attract or repel each other. You can change the magnitude of a magnetic force between two magnets by using magnets of different sizes. The magnitude of the magnetic force is smaller when the magnets are smaller.
The magnets in Pair 2 attract. The magnets in Pair 1 repel. But whether the magnets attract or repel affects only the direction of the magnetic force. It does not affect the magnitude of the magnetic force. Magnet sizes affect the magnitude of the magnetic force. Imagine magnets that are the same shape and made of the same material. The smaller the magnets, the smaller the magnitude of the magnetic force between them. Magnet A is the same size in both pairs. But Magnet B is smaller in Pair 1 than in Pair 2. So, the magnitude of the magnetic force is smaller in Pair 1 than in Pair 2.
Which animal is also adapted to use its neck to appear large and scary to a predator?
[ "lace monitor", "spectacled cobra" ]
1
Bearded dragons are lizards. Their predators include owls, eagles, and snakes. The uses its neck to appear large and scary to a predator. Figure: bearded dragon.
closed choice
grade5
natural science
biology
Adaptations
Animal adaptations: beaks, mouths, and necks
An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors. The shape of an animal's neck is one example of an adaptation. Animals' necks can be adapted in different ways. For example, a large frilled neck might help an animal appear dangerous to its predators. A long neck might help an animal get food from tall trees.
Look at the picture of the bearded dragon. When frightened, the bearded dragon can spread out its hood to appear larger and more dangerous. If a predator is nearby, the hood can help scare it away. Now look at each animal. Figure out which animal has a similar adaptation. The spectacled cobra has a hood around its neck. It uses its neck to appear larger and more dangerous to a predator. The lace monitor has a narrow neck. Its neck is not adapted to help it appear larger and more dangerous to a predator.
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Compare the motion of three cars. Which car was moving at the lowest speed?
[ "a car that moved 250miles east in 5hours", "a car that moved 65miles south in 5hours", "a car that moved 300miles north in 5hours" ]
1
closed choice
grade3
natural science
physics
Force and motion
Compare the speeds of moving objects
An object's speed tells you how fast the object is moving. Speed depends on both distance and time. Distance tells you how far the object has moved. One unit used to measure distance is the mile. Time tells you how long the object has spent moving. One unit used to measure time is the hour. Think about objects moving for the same amount of time. The object that is moving the slowest will go the shortest distance in that time. It is moving at the lowest speed.
Look at the distance each car moved and the time it took to move that distance. The direction each car moved does not affect its speed. Notice that each car moved for 5 hours. The car that moved 65 miles moved the shortest distance in that time. So, that car must have moved at the lowest speed.
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What is the temperature of the air on a cold, rainy day?
[ "42°C", "42°F" ]
1
Select the better estimate.
closed choice
grade6
natural science
units-and-measurement
Units and measurement
Estimate temperatures
Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. Temperature can be written with units of degrees Fahrenheit (°F) or Celsius (°C). Use the list below to compare the two units. 212°F | Water boils | 100°C 98.6°F | Body temperature | 37°C 68°F | Room temperature | 20°C 32°F | Water freezes | 0°C
The better estimate for the temperature of the air on a cold, rainy day is 42°F. 42°C is too hot.
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What is the source of the allusion in the sentence below? Nolan persisted despite his friends' attempts to tell him that this was a Gordian knot.
[ "a song", "ancient legend" ]
1
closed choice
grade11
language science
figurative-language
Literary devices
Recall the source of an allusion
An allusion is a brief mention of something or someone well known, often from mythology, history, or literature. An allusion lets you reference ideas from an entire story in just a few words. The protean nature of the disease makes it difficult to diagnose. The word protean is an allusion to the sea god Proteus in Greek mythology. Because the sea is constantly changing, to describe something as protean suggests that it is variable or in flux.
The source of the allusion Gordian knot is ancient legend. According to legend, Alexander the Great used his sword to slash an intricate knot by which a chariot was tied to a pole in the city of Gordium. The allusion Gordian knot means a highly complex problem.
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Complete the statement. Assume that the sled's mass did not change. The gravitational potential energy stored between the sled and Earth () as Tammy rode down the hill.
[ "stayed the same", "increased", "decreased" ]
2
Read the text about an object in motion. On a snowy day, Tammy rode her sled down a big hill.
closed choice
grade6
natural science
physics
Kinetic and potential energy
Identify changes in gravitational potential energy
Gravitational potential energy is stored between any two objects. So, for every object on or near Earth, there is gravitational potential energy stored between the object and Earth. The amount of gravitational potential energy stored between an object and Earth depends on the mass of the object. The amount of gravitational potential energy also depends on the distance between the object and the center of Earth. This distance increases when the object moves higher and decreases when the object moves lower. If the distance between an object and the center of Earth changes, the gravitational potential energy stored between the object and Earth will change. The table below shows how this change can happen. When an object's mass stays the same and its distance from the center of Earth... | Gravitational potential energy stored between the object and Earth... increases | increases decreases | decreases stays the same | stays the same
Think about how the distance between the sled and the center of Earth changed. The bottom of the hill was lower than the point where Tammy started sledding. As Tammy rode toward the bottom of the hill, the distance between the sled and the center of Earth decreased. So, the gravitational potential energy stored between the sled and Earth decreased as Tammy rode down the hill.
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Select the invertebrate.
[ "rockfish", "albatross", "leaf-curling spider", "whiptail lizard" ]
2
Hint: Insects, spiders, and worms are invertebrates.
closed choice
grade5
natural science
biology
Classification
Identify vertebrates and invertebrates
Vertebrates and invertebrates are both groups of animals. A vertebrate has a backbone. The backbone is made of many bones in an animal's back. A vertebrate's backbone helps connect the different parts of its body. In the drawings below, each vertebrate's backbone is colored orange. An invertebrate does not have a backbone. In fact, invertebrates do not have any bones! Some invertebrates have an outer cover on their body called an exoskeleton. Other invertebrates have a soft body.
Like other spiders, a leaf-curling spider is an invertebrate. It does not have a backbone. It has an exoskeleton. A whiptail lizard is a reptile. Like other reptiles, a whiptail lizard is a vertebrate. It has a backbone. A rockfish is a fish. Like other fish, a rockfish is a vertebrate. It has a backbone. An albatross is a bird. Like other birds, an albatross is a vertebrate. It has a backbone.
Identify the question that Camilla's experiment can best answer.
[ "Do the temperatures inside boxes depend on the sizes of the boxes?", "Do the insides of white boxes get hotter than the insides of black boxes when the boxes are left in the sun?" ]
1
The passage below describes an experiment. Read the passage and then follow the instructions below. Camilla glued lids onto 16 cardboard shoe boxes of equal size. She painted eight of the boxes black and eight of the boxes white. Camilla made a small hole in the side of each box and then stuck a thermometer partially into each hole so she could measure the temperatures inside the boxes. She placed the boxes in direct sunlight in her backyard. Two hours later, she measured the temperature inside each box. Camilla compared the average temperature inside the black boxes to the average temperature inside the white boxes. Figure: a shoebox painted black.
closed choice
grade6
natural science
science-and-engineering-practices
Designing experiments
Identify the experimental question
Experiments can be designed to answer specific questions. How can you identify the questions that a certain experiment can answer? In order to do this, you need to figure out what was tested and what was measured during the experiment. Imagine an experiment with two groups of daffodil plants. One group of plants was grown in sandy soil, and the other was grown in clay soil. Then, the height of each plant was measured. First, identify the part of the experiment that was tested. The part of an experiment that is tested usually involves the part of the experimental setup that is different or changed. In the experiment described above, each group of plants was grown in a different type of soil. So, the effect of growing plants in different soil types was tested. Then, identify the part of the experiment that was measured. The part of the experiment that is measured may include measurements and calculations. In the experiment described above, the heights of the plants in each group were measured. Experiments can answer questions about how the part of the experiment that is tested affects the part that is measured. So, the experiment described above can answer questions about how soil type affects plant height. Examples of questions that this experiment can answer include: Does soil type affect the height of daffodil plants? Do daffodil plants in sandy soil grow taller than daffodil plants in clay soil? Are daffodil plants grown in sandy soil shorter than daffodil plants grown in clay soil?
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Which type of sentence is this? As Charlie sat down on the rickety old chair, it abruptly collapsed beneath him.
[ "compound", "complex", "compound-complex", "simple" ]
1
closed choice
grade10
language science
grammar
Phrases and clauses
Is the sentence simple, compound, complex, or compound-complex?
A clause is a group of words that contains both a subject and a predicate. An independent clause is a complete thought that can stand alone as a sentence. A dependent clause (or subordinate clause) is not a complete thought and cannot stand alone as a sentence. the oranges on our tree are ripe The clause can stand alone. It is independent. after we pick up Kevin from work The clause cannot stand alone. It is dependent. A simple sentence is made up of a single independent clause. Ben and I spent all day relaxing by the pool. Some simple sentences have introductory phrases, but the introductory phrase is part of the predicate. In the winter, Ben usually wears his heavy coat. Ben usually wears his heavy coat in the winter. A compound sentence is made up of two independent clauses joined by a coordinating conjunction such as and, but, or, or so. We saw the flash of lightning, and seconds later we heard a rumble of thunder. A complex sentence is made up of an independent clause and a dependent clause. The dependent clause in a complex sentence usually begins with a subordinating conjunction or relative pronoun. Subordinating conjunctions include after, although, as, because, before, if, since, unless, until, when, and while. Relative pronouns include that, which, who, whom, or whose. If she ever gets the chance, Terri would love to visit the Egyptian pyramids. During his trip to Italy, Tony visited the Trevi Fountain, which is in Rome. A compound-complex sentence is made up of two or more independent clauses and one or more dependent clauses. After Samantha left work, she stopped at the bank, and then she went to the gym. Sometimes a dependent clause in a complex or compound-complex sentence can interrupt an independent clause. Orcas that are kept in captivity often have bent dorsal fins.
The sentence is complex. It is made up of an independent clause and a dependent clause. The dependent clause begins with the subordinating conjunction as. As Charlie sat down on the rickety old chair, it abruptly collapsed beneath him.
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Select the one animal that has all of the mammal traits listed above.
[ "Gray tree frogs hatch from eggs without shells. They live underwater when they are tadpoles. They move onto land when they become adults. The moist skin of adult gray tree frogs can be green or gray. The color of their skin helps them hide on rocks or plants.", "Bengal tigers are one of the world's largest living cats. They have black, white, and orange fur. Female Bengal tigers feed their offspring milk. Male Bengal tigers can be almost twice as large as females!" ]
1
Mammals are a group of animals with similar traits. The following traits can be used to identify mammals: They feed their offspring milk. They have fur or hair. Observe the animals and read the descriptions.
closed choice
grade4
natural science
biology
Classification
Use evidence to classify mammals, birds, fish, reptiles, and amphibians
Scientists sort animals with similar traits into groups. This is called classification. Classification helps scientists learn about how animals live. How do scientists classify animals? First, they make observations about an animal. Scientists observe the animal's traits, including its body parts and behavior. Then, scientists compare the animal's traits to other animals' traits. Scientists classify animals with similar traits into a group.
To decide if an animal is part of a group, look at the traits of the group. Mammals have the following traits: They feed their offspring milk. They have fur or hair. Compare each animal's traits to the group's traits. Select the animal with traits similar to the group's traits. A Bengal tiger has the following traits: It feeds its offspring milk. It has hair. A Bengal tiger has the traits of a mammal. A Bengal tiger is a mammal. A gray tree frog has the following traits: It spends part of its life in water and part on land. It has moist skin. It makes eggs with no shells. A gray tree frog does not have all of the traits of a mammal. A gray tree frog is an amphibian.
Complete the statement. Gold is ().
[ "an elementary substance", "a compound" ]
0
The model below represents gold. Gold is a precious metal that is often used to make jewelry.
closed choice
grade7
natural science
chemistry
Atoms and molecules
Classify elementary substances and compounds using models
There are more than 100 different chemical elements, or types of atoms. Chemical elements make up all of the substances around you. A substance may be composed of one chemical element or multiple chemical elements. Substances that are composed of only one chemical element are elementary substances. Substances that are composed of multiple chemical elements bonded together are compounds. Every chemical element is represented by its own atomic symbol. An atomic symbol may consist of one capital letter, or it may consist of a capital letter followed by a lowercase letter. For example, the atomic symbol for the chemical element fluorine is F, and the atomic symbol for the chemical element beryllium is Be. Scientists use different types of models to represent substances whose atoms are bonded in different ways. One type of model is a space-filling model. The space-filling model below represents the elementary substance zirconium. In a space-filling model, the balls represent atoms that are bonded together. The color of a ball represents a specific chemical element. The atomic symbol for that chemical element is shown in the legend.
Use the model to determine whether gold is an elementary substance or a compound. Step 1: Interpret the model. In the space-filling model shown above, all of the balls are the same color: . The legend shows that yellow represents the chemical element with the atomic symbol Au. So, the model shows you that gold is composed of one chemical element. Step 2: Determine whether the substance is an elementary substance or a compound. You know from Step 1 that gold is composed of only one chemical element. So, gold is an elementary substance.