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Lecture: Experiments have variables, or parts that change. You can design an experiment to investigate whether changing a variable between different groups has a specific outcome.
For example, imagine you want to find out whether adding fertilizer to soil affects the height of pea plants. You could investigate this question with the following experiment:
You grow one group of pea plants in soil with fertilizer and measure the height of the plants. This group shows you what happens when fertilizer is added to soil. Since fertilizer is the variable whose effect you are investigating, this group is an experimental group.
You grow another group of pea plants in soil without fertilizer and measure the height of the plants. Since this group shows you what happens when fertilizer is not added to the soil, it is a control group.
By comparing the results from the experimental group to the results from the control group, you can conclude whether adding fertilizer to the soil affects pea plant height.
Question: In this experiment, which were part of a control group?
Hint: The passage below describes an experiment.
Zeke grew ten on his back porch. He grew each plant in its own pot. Zeke noticed that his plants did not grow many leaves, and he wanted to see if earthworms could help them grow more.
Zeke divided his ten plants into two equal groups. He added three earthworms each to the soil in five of the pots. He did not add any earthworms to the other five pots. Two months later, he counted the number of leaves on each of the ten plants.
Figure: mint plants.
Choices:
A. the mint plants that did not get earthworms
B. the mint plants that got earthworms
Answer with the letter.
| 0A
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Lecture: A graphic organizer is a chart or picture that shows how ideas, facts, or topics are related to one another.
When you read, look for graphic organizers included in the text. You can use these images to find key information. You can also create your own graphic organizers with information that you've read. Doing this can help you think about the ideas in the text and easily review them.
When you write, you can use graphic organizers to organize your thoughts and plan your writing.
Question: Based on the continuum scale, which planet is larger than Mars?
Hint: This continuum scale shows the sizes of the inner planets of our solar system.
Choices:
A. Mercury
B. Earth
Answer with the letter.
| 1B
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Lecture: 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
Question: Which better describes the Kermadec Arc ecosystem?
Hint: Figure: Kermadec Arc.
The Kermadec Arc is a deep sea ecosystem in the southern Pacific Ocean.
Choices:
A. It has no sunlight. It also has many large swimming organisms.
B. It has no sunlight. It also has organisms that crawl or stick to the ground.
Answer with the letter.
| 1B
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Question: What is the capital of Michigan?
Choices:
A. Detroit
B. Lansing
C. Des Moines
D. Lincoln
Answer with the letter.
| 1B
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Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The strength of the magnetic force is the same in both pairs.
B. The magnetic force is weaker in Pair 2.
C. The magnetic force is weaker in Pair 1.
Answer with the letter.
| 0A
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Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnitude of the magnetic force is smaller in Pair 1.
B. The magnitude of the magnetic force is the same in both pairs.
C. The magnitude of the magnetic force is smaller in Pair 2.
Answer with the letter.
| 2C
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Lecture: 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 mouth is one example of an adaptation. Animals' mouths can be adapted in different ways. For example, a large mouth with sharp teeth might help an animal tear through meat. A long, thin mouth might help an animal catch insects that live in holes. Animals that eat similar food often have similar mouths.
Question: Which animal's mouth is also adapted for gnawing?
Hint: Brown rats eat plant matter, such as leaves, stems, and seeds. They eat by biting off small pieces at a time, or gnawing. The rat's mouth is adapted for gnawing.
Figure: brown rat.
Choices:
A. cougar
B. Podolsk mole rat
Answer with the letter.
| 1B
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Lecture: An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.
Different objects can have the same properties. You can use these properties to put objects into groups.
Question: Which property do these two objects have in common?
Hint: Select the better answer.
Choices:
A. yellow
B. stretchy
Answer with the letter.
| 0A
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Question: What is the capital of Maryland?
Choices:
A. Annapolis
B. Athens
C. Davenport
D. Dallas
Answer with the letter.
| 0A
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Lecture: An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks.
Question: Which bird's beak is also adapted to filter through mud?
Hint: Northern pintails eat plants that grow underwater or in mud. The shape of the 's beak is adapted to filter through mud for food.
The gathers muddy water in its beak and then pushes it out through gaps along the sides. Bits of food, such as plant roots, are left behind inside the pintail's beak.
Figure: northern pintail.
Choices:
A. common nighthawk
B. black swan
Answer with the letter.
| 1B
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Lecture: 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
Question: Which better describes the tide pool ecosystems in Tongue Point Marine Life Sanctuary?
Hint: Figure: Tongue Point Marine Life Sanctuary.
Tongue Point Marine Life Sanctuary is in western Washington State. The park is on the coast of the Pacific Ocean. It has many tide pool ecosystems.
Choices:
A. It has daily flooding and draining of seawater. It also has water that is rich in nutrients.
B. It has no sunlight. It also has daily flooding and draining of seawater.
Answer with the letter.
| 0A
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Lecture: 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.
Question: Which of these states is farthest west?
Choices:
A. Connecticut
B. Maine
C. Pennsylvania
D. Vermont
Answer with the letter.
| 2C
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Lecture: 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.
Question: Which property do these three objects have in common?
Hint: Select the best answer.
Choices:
A. blue
B. scratchy
C. transparent
Answer with the letter.
| 1B
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Lecture: 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!
Question: In this food chain, the diatom is a producer. Why?
Hint: This diagram shows a food chain from a tropical coral reef ecosystem off the coast of Australia.
Choices:
A. It eats a consumer.
B. It makes its own food.
C. It eats another organism.
Answer with the letter.
| 1B
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Question: Which country is highlighted?
Choices:
A. New Zealand
B. Papua New Guinea
C. Solomon Islands
D. Australia
Answer with the letter.
| 3D
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Lecture: An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.
Question: Which animal is also adapted to be camouflaged in a sandy desert?
Hint: Camels live in dry places such as deserts. The is adapted to be camouflaged in a sandy desert.
Figure: camel.
Choices:
A. bearded dragon
B. scarlet snake
Answer with the letter.
| 0A
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Lecture: Birds, mammals, fish, reptiles, and amphibians are groups of animals. The animals in each group have traits in common.
Scientists sort animals into groups based on traits they have in common. This process is called classification.
Question: Select the bird below.
Hint: Birds have feathers, two wings, and a beak. A keel-billed toucan is an example of a bird.
Choices:
A. Chinese alligator
B. pelican
Answer with the letter.
| 1B
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Lecture: A continent is one of the seven largest areas of land on earth.
Question: Which continent is highlighted?
Choices:
A. South America
B. Antarctica
C. Africa
D. Asia
Answer with the letter.
| 1B
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Lecture: A material is a type of matter. Wood, glass, metal, and plastic are common materials.
Question: Which material is this aluminum foil made of?
Choices:
A. plastic
B. metal
Answer with the letter.
| 1B
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Question: What is the name of the colony shown?
Choices:
A. Connecticut
B. North Carolina
C. Maryland
D. Indiana
Answer with the letter.
| 1B
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Question: Which state is highlighted?
Choices:
A. Oregon
B. California
C. Montana
D. Nevada
Answer with the letter.
| 2C
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Lecture: An environment includes all of the biotic, or living, and abiotic, or nonliving, things in an area. An ecosystem is created by the relationships that form among the biotic and abiotic parts of an environment.
There are many different types of terrestrial, or land-based, ecosystems. Here are some ways in which terrestrial ecosystems can differ from each other:
the pattern of weather, or climate
the type of soil
the organisms that live there
Question: Which statement describes the Catoctin Mountain Park ecosystem?
Hint: Figure: Catoctin Mountain Park.
Catoctin Mountain Park is a temperate deciduous forest ecosystem in Maryland. Most of this forest was cut down for its wood in the early 1900s. But since the 1940s, conservation efforts have allowed the forest to return to much of this park.
Choices:
A. It has only a few types of trees.
B. It has soil that is poor in nutrients.
Answer with the letter.
| 0A
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Question: What is the capital of Vermont?
Choices:
A. Olympia
B. Concord
C. Burlington
D. Montpelier
Answer with the letter.
| 3D
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Lecture: Birds, mammals, fish, reptiles, and amphibians are groups of animals. Scientists sort animals into each group based on traits they have in common. This process is called classification.
Classification helps scientists learn about how animals live. Classification also helps scientists compare similar animals.
Question: Select the fish below.
Hint: Fish live underwater. They have fins, not limbs.
Fish are cold-blooded. The body temperature of cold-blooded animals depends on their environment.
A tiger shark is an example of a fish.
Choices:
A. green chameleon
B. goldfish
C. fruit bat
D. great crested newt
Answer with the letter.
| 1B
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Lecture: 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.
Question: Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?
Hint: 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.
Choices:
A. sample A
B. neither; the samples have the same temperature
C. sample B
Answer with the letter.
| 0A
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Lecture: 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: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Question: Will these magnets attract or repel each other?
Hint: Two magnets are placed as shown.
Choices:
A. repel
B. attract
Answer with the letter.
| 1B
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Lecture: Magnets can pull or push on other magnets without touching them. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes are called magnetic forces.
Magnetic forces are strongest at the magnets' poles, or ends. Every magnet has two poles: a north pole (N) and a south pole (S).
Here are some examples of magnets. Their poles are shown in different colors and labeled.
Whether a magnet attracts or repels other magnets depends on the positions of its poles.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Question: Will these magnets attract or repel each other?
Hint: Two magnets are placed as shown.
Choices:
A. repel
B. attract
Answer with the letter.
| 0A
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Question: What can Perry and Antonio trade to each get what they want?
Hint: 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.
Perry and Antonio open their lunch boxes in the school cafeteria. Both of them could be happier with their lunches. Perry wanted broccoli in his lunch and Antonio was hoping for tomatoes. Look at the images of their lunches. Then answer the question below.
Choices:
A. Antonio can trade his almonds for Perry's tomatoes.
B. Perry can trade his tomatoes for Antonio's sandwich.
C. Perry can trade his tomatoes for Antonio's broccoli.
D. Antonio can trade his broccoli for Perry's oranges.
Answer with the letter.
| 2C
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Lecture: 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 volume of a planet is a very large quantity. Large quantities such as this are often written in scientific notation.
For example, the volume of Jupiter is 1,430,000,000,000,000 km^3. In scientific notation, Jupiter's volume is written as 1.43 x 10^15 km^3.
To compare two numbers written in scientific notation, compare their exponents. The bigger the exponent is, the bigger the number is. For example:
1.43 x 10^15 is larger than 1.43 x 10^12
If their exponents are equal, compare the first numbers. For example:
1.43 x 10^15 is larger than 1.25 x 10^15
Question: Is the following statement about our solar system true or false?
Earth is the largest planet that is made mainly of rock.
Hint: Use the data to answer the question below.
Choices:
A. true
B. false
Answer with the letter.
| 0A
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Lecture: 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.
Question: Look at the models of molecules below. Select the elementary substance.
Choices:
A. ethane
B. carbon tetraiodide
C. oxygen
Answer with the letter.
| 2C
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Lecture: 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 greater when there is a smaller distance between the magnets.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnitude of the magnetic force is greater in Pair 2.
B. The magnitude of the magnetic force is the same in both pairs.
C. The magnitude of the magnetic force is greater in Pair 1.
Answer with the letter.
| 2C
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Lecture: 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: north and south.
Here are some examples of magnets. The north pole of each magnet is labeled N, and the south pole is labeled S.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Question: Will these magnets attract or repel each other?
Hint: Two magnets are placed as shown.
Choices:
A. attract
B. repel
Answer with the letter.
| 0A
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Lecture: Magnets can pull or push on other magnets without touching them. When magnets attract, they pull together. When magnets repel, they push apart. These pulls and pushes are called magnetic forces.
Magnetic forces are strongest at the magnets' poles, or ends. Every magnet has two poles: a north pole (N) and a south pole (S).
Here are some examples of magnets. Their poles are shown in different colors and labeled.
Whether a magnet attracts or repels other magnets depends on the positions of its poles.
If opposite poles are closest to each other, the magnets attract. The magnets in the pair below attract.
If the same, or like, poles are closest to each other, the magnets repel. The magnets in both pairs below repel.
Question: Will these magnets attract or repel each other?
Hint: Two magnets are placed as shown.
Choices:
A. repel
B. attract
Answer with the letter.
| 0A
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Question: What is the capital of Oklahoma?
Choices:
A. Little Rock
B. Tulsa
C. Oklahoma City
D. Trenton
Answer with the letter.
| 2C
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Lecture: 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?
Question: Identify the question that Julia and Andy's experiment can best answer.
Hint: The passage below describes an experiment. Read the passage and then follow the instructions below.
Julia applied a thin layer of wax to the underside of her snowboard and rode the board straight down a hill. Then, she removed the wax and rode the snowboard straight down the hill again. She repeated the rides four more times, alternating whether she rode with a thin layer of wax on the board or not. Her friend Andy timed each ride. Julia and Andy calculated the average time it took to slide straight down the hill on the snowboard with wax compared to the average time on the snowboard without wax.
Figure: snowboarding down a hill.
Choices:
A. Does Julia's snowboard slide down a hill in less time when it has a layer of wax or when it does not have a layer of wax?
B. Does Julia's snowboard slide down a hill in less time when it has a thin layer of wax or a thick layer of wax?
Answer with the letter.
| 0A
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Question: What is the name of the colony shown?
Choices:
A. West Virginia
B. Virginia
C. Delaware
D. North Carolina
Answer with the letter.
| 1B
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Lecture: 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?
Question: Identify the question that Shawn's experiment can best answer.
Hint: The passage below describes an experiment. Read the passage and then follow the instructions below.
Shawn divided 40 evenly among eight paper bags and sealed the bags. He poked 20 small holes in four of the bags and left the other four without holes. He kept the bags at room temperature for three days. Then, Shawn opened the bags and counted the number of brown spots on each banana. He compared the average number of brown spots on bananas from bags with holes to the average number of brown spots on bananas from bags without holes.
Figure: unripe bananas.
Choices:
A. Do bananas develop more brown spots when they are kept at room temperature compared to in a cold refrigerator?
B. Do bananas develop more brown spots if they are kept in bags with holes compared to bags without holes?
Answer with the letter.
| 1B
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Lecture: An organism's genes contain information about its proteins. Each gene encodes, or contains the instructions for making, one protein or a group of proteins.
A permanent change in a gene is called a mutation. Because a mutation changes a gene, the mutation may change the structure of the protein encoded by that gene.
The function of a protein depends on its structure. So, if a mutation in a gene changes a protein's structure, the mutation may also change the protein's function.
An organism's observable traits are affected by the functions of its proteins. So, a gene mutation that affects a protein's function may also affect an organism's observable traits.
Question: Complete the sentence.
The mutation in the () affected the structure and function of the ().
Hint: The following passage describes the effects of a gene mutation, which is a permanent change in a gene. Read the passage and then follow the instructions below.
Some plant proteins control how flowers grow and develop. In Arabidopsis thaliana (A. thaliana) plants, one of these proteins is called ULTRAPETALA1. The ULTRAPETALA1 protein is encoded by the ULT1 gene.
The ULTRAPETALA1 protein allows only a specific number of cells in the growing flower bud to divide and form petals. This results in A. thaliana flowers with four petals.
A certain A. thaliana plant had a mutation in the ULT1 gene that caused the plant to have flowers with six petals instead of four. Compared to the ULT1 gene without a mutation, the mutated ULT1 gene encoded a form of the ULTRAPETALA1 protein with a different structure.
This different form of the ULTRAPETALA1 protein allowed more cells than normal to grow and form petals.
Figure: an A. thaliana flower with four petals.
Choices:
A. ULTRAPETALA1 protein . . . ULT1 gene
B. ULT1 gene . . . ULTRAPETALA1 protein
Answer with the letter.
| 1B
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Lecture: Scientists record climate data from places around the world. Temperature is one type of climate data. Scientists collect data over many years. They can use this data to calculate the average temperature for each month. The average temperature can be used to describe the climate of a location.
A line graph can be used to show the average temperature each month. Months with higher dots on the graph have higher average temperatures.
Question: Which month has the lowest average temperature in Amsterdam?
Hint: Use the graph to answer the question below.
Choices:
A. January
B. February
C. November
Answer with the letter.
| 1B
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Lecture: Experiments have variables, or parts that change. You can design an experiment to find out how one variable affects another variable. For example, imagine that you want to find out if fertilizer affects the number of tomatoes a tomato plant grows. To answer this question, you decide to set up two equal groups of tomato plants. Then, you add fertilizer to the soil of the plants in one group but not in the other group. Later, you measure the effect of the fertilizer by counting the number of tomatoes on each plant.
In this experiment, the amount of fertilizer added to the soil and the number of tomatoes were both variables.
The amount of fertilizer added to the soil was an independent variable because it was the variable whose effect you were investigating. This type of variable is called independent because its value does not depend on what happens after the experiment begins. Instead, you decided to give fertilizer to some plants and not to others.
The number of tomatoes was a dependent variable because it was the variable you were measuring. This type of variable is called dependent because its value can depend on what happens in the experiment.
Question: Which of the following was an independent variable in this experiment?
Hint: The passage below describes an experiment. Read the passage and think about the variables that are described.
Pablo wanted to grow cucumbers from seeds. He read that using a heating pad to heat up potting soil could help make seeds germinate, or sprout, faster. Pablo wondered whether the temperature of the heating pad would affect how quickly the seeds germinated.
Pablo prepared two potting trays, each made up of ten small pots of soil. He planted one cucumber seed in each small pot and arranged the potting trays near a sunny window. He set an electric heating pad to 75°F and placed it under one potting tray. He set a second heating pad to 85°F and placed it under the other potting tray. Pablo observed the pots daily, and he counted the number of days it took until a seed germinated in each pot.
Hint: An independent variable is a variable whose effect you are investigating. A dependent variable is a variable that you measure.
Figure: germinating plants in a potting tray.
Choices:
A. the number of days until a seed germinated
B. the temperature of the heating pad
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnetic force is stronger in Pair 1.
B. The strength of the magnetic force is the same in both pairs.
C. The magnetic force is stronger in Pair 2.
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Which animal's limbs are also adapted for swimming?
Hint: Humpback whales are found in the world's oceans. They live underwater, but come to the surface to breathe air.
The has flippers for limbs. Its limbs are adapted for swimming.
Figure: humpback whale.
Choices:
A. nilgai
B. California sea lion
Answer with the letter.
| 1B
|
|
Lecture: 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 greater when there is a smaller distance between the magnets.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnitude of the magnetic force is greater in Pair 2.
B. The magnitude of the magnetic force is greater in Pair 1.
C. The magnitude of the magnetic force is the same in both pairs.
Answer with the letter.
| 0A
|
|
Lecture: 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
Question: Which solution has a higher concentration of pink particles?
Hint: The diagram below is a model of two solutions. Each pink ball represents one particle of solute.
Choices:
A. neither; their concentrations are the same
B. Solution B
C. Solution A
Answer with the letter.
| 2C
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|
Lecture: An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The shape of a bird's beak is one example of an adaptation. Birds' beaks can be adapted in different ways. For example, a sharp hooked beak might help a bird tear through meat easily. A short, thick beak might help a bird break through a seed's hard shell. Birds that eat similar food often have similar beaks.
Question: Which bird's beak is also adapted to crack hard seeds?
Hint: Evening grosbeaks eat small, hard seeds. The shape of the 's beak is adapted to crack open small, hard seeds.
Figure: evening grosbeak.
Choices:
A. indigo bunting
B. Asian openbill
Answer with the letter.
| 0A
|
|
Question: What is the capital of Pennsylvania?
Choices:
A. Pittsburgh
B. Philadelphia
C. Harrisburg
D. Montpelier
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Which part of the watermelon plant makes the seeds?
Hint: A watermelon plant can grow seeds.
Choices:
A. the fruit
B. the flowers
Answer with the letter.
| 1B
|
|
Question: What is the capital of Maryland?
Choices:
A. Jefferson City
B. Albany
C. Annapolis
D. Dover
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Which of these states is farthest west?
Choices:
A. Massachusetts
B. South Dakota
C. South Carolina
D. Maine
Answer with the letter.
| 1B
|
|
Lecture: An organism's genes contain information about its proteins. Each gene encodes, or contains the instructions for making, one protein or a group of proteins.
A permanent change in a gene is called a mutation. Because a mutation changes a gene, the mutation may change the structure of the protein encoded by that gene.
The function of a protein depends on its structure. So, if a mutation in a gene changes a protein's structure, the mutation may also change the protein's function.
An organism's observable traits are affected by the functions of its proteins. So, a gene mutation that affects a protein's function may also affect an organism's observable traits.
Question: Complete the sentence.
The mutation in the () affected the structure and function of the ().
Hint: The following passage describes the effects of a gene mutation, which is a permanent change in a gene. Read the passage and then follow the instructions below.
A pea plant's height is affected by substances that are made inside the plant's cells. One of these substances is called gibberellin.
Gibberellin is made in a pea plant's cells by a protein called GA 3-oxidase. The GA 3-oxidase protein is encoded by the LH gene.
A certain pea plant had a mutation in its LH gene. Compared to the LH gene without a mutation, the mutated LH gene encoded a form of the GA 3-oxidase protein with a different structure.
This different form of the GA 3-oxidase protein could make only a small amount of gibberellin. The plant with the mutation grew to a shorter height than pea plants containing more gibberellin.
Figure: pea plants with different amounts of gibberellin.
Choices:
A. GA 3-oxidase protein . . . LH gene
B. LH gene . . . GA 3-oxidase protein
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnitude of the magnetic force is smaller in Pair 1.
B. The magnitude of the magnetic force is smaller in Pair 2.
C. The magnitude of the magnetic force is the same in both pairs.
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Complete the statement.
Hydrazine is ().
Hint: The model below represents a molecule of hydrazine. Hydrazine is used in some types of rocket fuels.
Choices:
A. an elementary substance
B. a compound
Answer with the letter.
| 1B
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|
Question: Which country is highlighted?
Choices:
A. Samoa
B. Papua New Guinea
C. New Zealand
D. Australia
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Which of these states is farthest south?
Choices:
A. Colorado
B. Pennsylvania
C. Oregon
D. Connecticut
Answer with the letter.
| 0A
|
|
Lecture: Oceans are huge bodies of salt water. The world has five oceans. All of the oceans are connected, making one world ocean.
Question: Which ocean is highlighted?
Choices:
A. the Atlantic Ocean
B. the Pacific Ocean
C. the Arctic Ocean
D. the Southern Ocean
Answer with the letter.
| 0A
|
|
Lecture: 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?
Question: Identify the question that Jack's experiment can best answer.
Hint: The passage below describes an experiment. Read the passage and then follow the instructions below.
Jack 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. Jack 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.
Choices:
A. Do steel nails take fewer days to rust in water compared to vinegar?
B. Do steel nails rust in fewer days when submerged in a large volume of liquid compared to a small volume?
Answer with the letter.
| 0A
|
|
Question: What is the capital of Rhode Island?
Choices:
A. Augusta
B. Newport
C. Trenton
D. Providence
Answer with the letter.
| 3D
|
|
Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnitude of the magnetic force is the same in both pairs.
B. The magnitude of the magnetic force is smaller in Pair 2.
C. The magnitude of the magnetic force is smaller in Pair 1.
Answer with the letter.
| 0A
|
|
Lecture: A continent is one of the major land masses on the earth. Most people say there are seven continents.
Question: Which continent is highlighted?
Choices:
A. Europe
B. South America
C. North America
D. Antarctica
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Which property matches this object?
Hint: Select the better answer.
Choices:
A. scratchy
B. yellow
Answer with the letter.
| 1B
|
|
Lecture: 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!
Question: Is schist a mineral or a rock?
Hint: Schist has the following properties:
solid
found in nature
no fixed crystal structure
hard
made mostly of pyroxene
not made by living things
Choices:
A. mineral
B. rock
Answer with the letter.
| 1B
|
|
Question: What is the name of the colony shown?
Choices:
A. Maryland
B. New Hampshire
C. South Carolina
D. Georgia
Answer with the letter.
| 0A
|
|
Lecture: 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.
Question: Which property do these four objects have in common?
Hint: Select the best answer.
Choices:
A. transparent
B. slippery
C. opaque
Answer with the letter.
| 1B
|
|
Lecture: An object has different properties. A property of an object can tell you how it looks, feels, tastes, or smells.
Different objects can have the same properties. You can use these properties to put objects into groups.
Question: Which property do these two objects have in common?
Hint: Select the better answer.
Choices:
A. soft
B. slippery
Answer with the letter.
| 1B
|
|
Lecture: An adaptation is an inherited trait that helps an organism survive or reproduce. Adaptations can include both body parts and behaviors.
The color, texture, and covering of an animal's skin are examples of adaptations. Animals' skins can be adapted in different ways. For example, skin with thick fur might help an animal stay warm. Skin with sharp spines might help an animal defend itself against predators.
Question: Which animal's skin is better adapted to hurt an attacking predator?
Hint: Echidnas have sharp spines covering much of their skin. These spines are called quills. The skin of the is adapted to hurt an attacking predator.
Figure: echidna.
Choices:
A. thorny devil
B. European robin
Answer with the letter.
| 0A
|
|
Lecture: 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.
Question: What is the expected ratio of offspring that do not have Marfan syndrome to offspring that have Marfan syndrome? Choose the most likely ratio.
Hint: This passage describes the Marfan syndrome trait in humans:
Marfan syndrome is a condition that affects a protein called fibrillin. Fibrillin helps support many parts of the human body and also affects growth. Humans with Marfan syndrome tend to be taller than average and have long limbs, fingers, and toes. They may also have heart problems and other organ issues.
In a group of humans, some individuals have Marfan syndrome and others do not. In this group, the gene for the Marfan syndrome trait has two alleles. The allele for having Marfan syndrome (M) is dominant over the allele for not having Marfan syndrome (m).
This Punnett square shows a cross between two humans.
Choices:
A. 4:0
B. 0:4
C. 3:1
D. 1:3
E. 2:2
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Which animal's feet are also adapted for walking on large, floating leaves?
Hint: s live near rivers and lakes. They eat insects and snails that live on plants floating on the surface of the water.
The feet of the jacana are adapted for walking on large, floating leaves. The jacana uses its feet to spread its weight out over a wide area. This helps the bird walk on the leaves without sinking into the water.
Figure: African jacana.
Choices:
A. ostrich
B. northern jacana
Answer with the letter.
| 1B
|
|
Question: What is the capital of Nevada?
Choices:
A. Carson City
B. Trenton
C. Las Vegas
D. Salem
Answer with the letter.
| 0A
|
|
Question: What can Patty and Tisha trade to each get what they want?
Hint: 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.
Patty and Tisha open their lunch boxes in the school cafeteria. Neither Patty nor Tisha got everything that they wanted. The table below shows which items they each wanted:
Look at the images of their lunches. Then answer the question below.
Patty's lunch Tisha's lunch
Choices:
A. Tisha can trade her broccoli for Patty's oranges.
B. Patty can trade her tomatoes for Tisha's broccoli.
C. Tisha can trade her almonds for Patty's tomatoes.
D. Patty can trade her tomatoes for Tisha's carrots.
Answer with the letter.
| 1B
|
|
Lecture: A change in an object's temperature indicates a change in the object's thermal energy:
An increase in temperature shows that the object's thermal energy increased. So, thermal energy was transferred into the object from its surroundings.
A decrease in temperature shows that the object's thermal energy decreased. So, thermal energy was transferred out of the object to its surroundings.
Question: During this time, thermal energy was transferred from () to ().
Hint: Two identical greenhouses were next to each other. There were solar panels on the roof of one greenhouse but not on the roof of the other greenhouse. This table shows how the temperature of each greenhouse changed over 2hours.
Choices:
A. the surroundings . . . each greenhouse
B. each greenhouse . . . the surroundings
Answer with the letter.
| 0A
|
|
Lecture: An environment includes all of the biotic, or living, and abiotic, or nonliving, things in an area. An ecosystem is created by the relationships that form among the biotic and abiotic parts of an environment.
There are many different types of terrestrial, or land-based, ecosystems. Here are some ways in which terrestrial ecosystems can differ from each other:
the pattern of weather, or climate
the type of soil
the organisms that live there
Question: Which statement describes the Białowieża Forest ecosystem?
Hint: Figure: Białowieża Forest.
The Białowieża Forest is a temperate deciduous forest ecosystem located in Poland and Belarus. It is one of the largest and oldest forests in Europe.
Choices:
A. It has soil that is poor in nutrients.
B. It has soil that is rich in nutrients.
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Is the following statement about our solar system true or false?
50% of the planets are made mainly of gas.
Hint: Use the data to answer the question below.
Choices:
A. false
B. true
Answer with the letter.
| 0A
|
|
Question: According to the text, what evidence of a volcanic eruption did the captain observe?
Hint: Before sunrise on November 14, 1963, the crew of the fishing boat Isleifur II had just finished putting their lines in the ocean off the southern coast of Iceland. As the crew waited to have breakfast, a strong smell of sulfur drifted over the boat. At first, crew members thought that the cook had burned the eggs or that something was wrong with the boat's engine. But when the sun started to rise, the crew saw black smoke billowing from the water a few kilometers away.
The captain of the Isleifur II assumed the smoke was coming from a boat that was on fire, so he sailed closer to try to help. As the Isleifur II approached the smoke, the surface of the sea grew rough. The captain and crew saw flashes of lightning in the column of smoke and glowing pieces of molten rock shooting up out of the water. The captain realized this was not a burning boat. It was a volcano erupting under the water!
Figure: the erupting undersea volcano seen by the sailors on the Isleifur II.
Choices:
A. He heard a report on the radio warning about a volcanic eruption.
B. He smelled sulfur and then realized it was not coming from his boat.
C. He knew his crew had finished putting their fishing lines in the ocean.
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: What is the expected ratio of offspring that have Thomsen disease to offspring that do not have Thomsen disease? Choose the most likely ratio.
Hint: This passage describes the Thomsen disease trait in humans:
Thomsen disease is a condition that causes temporary muscle stiffness. When a human with Thomsen disease first contracts a resting muscle, the muscle is slow to relax and may stay contracted for a while. But after repeated use, the muscle can contract and relax normally. This is known as the warm-up effect.
In a group of humans, some individuals have Thomsen disease and others do not. In this group, the gene for the Thomsen disease trait has two alleles. The allele for not having Thomsen disease (m) is recessive to the allele for having Thomsen disease (M).
This Punnett square shows a cross between two humans.
Choices:
A. 2:2
B. 4:0
C. 0:4
D. 3:1
E. 1:3
Answer with the letter.
| 0A
|
|
Lecture: Scientists record climate data from places around the world. Precipitation, or rain and snow, is one type of climate data. Scientists collect data over many years. They can use this data to calculate the average precipitation for each month. The average precipitation can be used to describe the climate of a location.
A bar graph can be used to show the average amount of precipitation each month. Months with taller bars have more precipitation on average.
Question: Which three months have over 200millimeters of precipitation in Singapore?
Hint: Use the graph to answer the question below.
Choices:
A. February, March, and April
B. May, June, and July
C. November, December, and January
Answer with the letter.
| 2C
|
|
Lecture: 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.
In a Punnett square, each box represents a different outcome, or result. Each of the four outcomes is equally likely to happen. Each box represents one way the parents' alleles can combine to form an offspring's genotype. Because there are four boxes in the Punnett square, there are four possible outcomes.
An event is a set of one or more outcomes. The probability of an event is a measure of how likely the event is to happen. This probability is a number between 0 and 1, and it can be written as a fraction:
probability of an event = number of ways the event can happen / number of equally likely outcomes
You can use a Punnett square to calculate the probability that a cross will produce certain offspring. For example, the Punnett square below has two boxes with the genotype Ff. It has one box with the genotype FF and one box with the genotype ff. This means there are two ways the parents' alleles can combine to form Ff. There is one way they can combine to form FF and one way they can combine to form ff.
| F | f
F | FF | Ff
f | Ff | ff
Consider an event in which this cross produces an offspring with the genotype ff. The probability of this event is given by the following fraction:
number of ways the event can happen / number of equally likely outcomes = number of boxes with the genotype ff / total number of boxes = 1 / 4.
Question: What is the probability that a budgerigar parakeet produced by this cross will have blue body feathers?
Hint: In a group of budgerigar parakeets, some individuals have green body feathers and others have blue body feathers. In this group, the gene for the body feather color trait has two alleles. The allele for blue body feathers (b) is recessive to the allele for green body feathers (B).
This Punnett square shows a cross between two budgerigar parakeets.
Choices:
A. 1/4
B. 0/4
C. 3/4
D. 2/4
E. 4/4
Answer with the letter.
| 4E
|
|
Question: Which country is highlighted?
Choices:
A. Nauru
B. New Zealand
C. Kiribati
D. Australia
Answer with the letter.
| 3D
|
|
Question: What is the capital of Kentucky?
Choices:
A. Atlanta
B. Frankfort
C. Carson City
D. Nashville
Answer with the letter.
| 1B
|
|
Lecture: Birds, mammals, fish, reptiles, and amphibians are groups of animals. Scientists sort animals into each group based on traits they have in common. This process is called classification.
Classification helps scientists learn about how animals live. Classification also helps scientists compare similar animals.
Question: Select the bird below.
Hint: Birds have feathers, two wings, and a beak.
Birds are warm-blooded. Warm-blooded animals can control their body temperature.
A red-tailed hawk is an example of a bird.
Choices:
A. robin
B. porcupinefish
C. tiger shark
D. great crested newt
Answer with the letter.
| 0A
|
|
Question: What is the capital of Connecticut?
Choices:
A. Providence
B. Albany
C. Hartford
D. Bridgeport
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Think about the magnetic force between the magnets in each pair. Which of the following statements is true?
Hint: 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.
Choices:
A. The magnetic force is weaker in Pair 1.
B. The strength of the magnetic force is the same in both pairs.
C. The magnetic force is weaker in Pair 2.
Answer with the letter.
| 2C
|
|
Lecture: 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.
Question: Select the organism in the same species as the Grevy's zebra.
Hint: This organism is a Grevy's zebra. Its scientific name is Equus grevyi.
Choices:
A. Macropus giganteus
B. Equus grevyi
C. Macropus rufus
Answer with the letter.
| 1B
|
|
Question: What is the capital of New Hampshire?
Choices:
A. Newport
B. Concord
C. Boston
D. Albany
Answer with the letter.
| 1B
|
|
Lecture: A continent is one of the major land masses on the earth. Most people say there are seven continents.
Question: Which continent is highlighted?
Choices:
A. Africa
B. North America
C. Europe
D. Australia
Answer with the letter.
| 3D
|
|
Question: What is the capital of Kansas?
Choices:
A. Frankfort
B. Des Moines
C. Topeka
D. Jefferson City
Answer with the letter.
| 2C
|
|
Question: What is the capital of Pennsylvania?
Choices:
A. Pittsburgh
B. Harrisburg
C. Hartford
D. Nashville
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Is the following statement about our solar system true or false?
There are twice as many ice planets as rocky planets.
Hint: Use the data to answer the question below.
Choices:
A. false
B. true
Answer with the letter.
| 0A
|
|
Lecture: 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 volume of a planet is a very large quantity. Large quantities such as this are often written in scientific notation.
For example, the volume of Jupiter is 1,430,000,000,000,000 km^3. In scientific notation, Jupiter's volume is written as 1.43 x 10^15 km^3.
To compare two numbers written in scientific notation, first compare their exponents. The bigger the exponent is, the bigger the number is. For example:
1.43 x 10^15 is larger than 1.43 x 10^12
If their exponents are equal, compare the first numbers. For example:
1.43 x 10^15 is larger than 1.25 x 10^15
To multiply a number written in scientific notation by a power of 10, write the multiple of 10 as 10 raised to an exponent. Then, add the exponents. For example:
1.43 x 10^15 · 1000
= 1.43 x 10^15 · 10^3
= 1.43 x 10^(15 + 3)
= 1.43 x 10^18
Question: Is the following statement about our solar system true or false?
The volume of Mars is more than ten times as large as Mercury's.
Hint: Use the data to answer the question below.
Choices:
A. false
B. true
Answer with the letter.
| 0A
|
|
Lecture: 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.
Question: Which of the following could Leon's test show?
Hint: 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.
Leon was a mechanical engineer who was designing to record temperature, precipitation, and wind speed. The weather station would be used in a town where the highest recorded temperature was 40°C. Leon wanted to make sure the weather station would work even in unusually warm weather.
So, he set an indoor test chamber to 50°C with low moisture and no wind. He left the weather station in the chamber overnight. The next day, he checked to see if the weather station displayed accurate measurements after 24 hours at 50°C.
Figure: a weather station.
Choices:
A. how well the weather station would work when it was windy
B. if the weather station would work when the temperature was 50°C
Answer with the letter.
| 1B
|
|
Question: What can Lexi and Cindy trade to each get what they want?
Hint: 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.
Lexi and Cindy open their lunch boxes in the school cafeteria. Neither Lexi nor Cindy got everything that they wanted. The table below shows which items they each wanted:
Look at the images of their lunches. Then answer the question below.
Lexi's lunch Cindy's lunch
Choices:
A. Lexi can trade her tomatoes for Cindy's broccoli.
B. Cindy can trade her almonds for Lexi's tomatoes.
C. Cindy can trade her broccoli for Lexi's oranges.
D. Lexi can trade her tomatoes for Cindy's carrots.
Answer with the letter.
| 0A
|
|
Question: Which term matches the picture?
Hint: Read the text.
When you think of muscles, you might think of the ones in your legs or arms that you use to help you move. These types of muscles are called striated muscles. If you look at them under a microscope, the cells appear rectangular and striped. There are other kinds of muscles, though, called smooth muscles. The cells that make up smooth muscles are oval shaped and not striped. They are found in places like the digestive system, where they help to keep food moving.
Choices:
A. striated muscles
B. smooth muscles
Answer with the letter.
| 1B
|
|
Lecture: 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.
Question: Is the following statement about our solar system true or false?
The volume of Mars is more than three times as large as Mercury's.
Hint: Use the data to answer the question below.
Choices:
A. true
B. false
Answer with the letter.
| 1B
|
|
Lecture: An organism's common name is the name that people normally call the organism. Common names often contain words you know.
An organism's scientific name is the name scientists use to identify the organism. Scientific names often contain words that are not used in everyday English.
Scientific names are written in italics, but common names are usually not. The first word of the scientific name is capitalized, and the second word is not. For example, the common name of the animal below is giant panda. Its scientific name is Ailuropoda melanoleuca.
Question: Which is this organism's scientific name?
Hint: This organism is a zebra dove. It is also called Geopelia striata.
Choices:
A. Geopelia striata
B. zebra dove
Answer with the letter.
| 0A
|
|
Question: Which state is highlighted?
Choices:
A. California
B. New Mexico
C. Hawaii
D. Nevada
Answer with the letter.
| 0A
|
|
Lecture: 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.
Question: Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?
Hint: 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.
Choices:
A. sample B
B. neither; the samples have the same temperature
C. sample A
Answer with the letter.
| 0A
|
|
Lecture: 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 copper.
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.
Question: Complete the statement.
Zinc is ().
Hint: The model below represents zinc. Zinc is a metal that is used to make batteries and musical instruments.
Choices:
A. an elementary substance
B. a compound
Answer with the letter.
| 0A
|
|
Lecture: 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.
Question: Compare the average kinetic energies of the particles in each sample. Which sample has the higher temperature?
Hint: 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.
Choices:
A. neither; the samples have the same temperature
B. sample A
C. sample B
Answer with the letter.
| 1B
|
|
Question: What is the capital of Oregon?
Choices:
A. Phoenix
B. Portland
C. Columbus
D. Salem
Answer with the letter.
| 3D
|
|
Question: Which country is highlighted?
Choices:
A. Solomon Islands
B. Nauru
C. Vanuatu
D. Fiji
Answer with the letter.
| 2C
|
|
Lecture: A grid is made up of lines of squares. They are organized in rows and columns. A grid can help you use a map.
A row is a line of squares that goes from side to side. Rows are marked with letters.
A column is a line of squares that goes up and down. Columns are marked with numbers.
Question: Which i in column 1?
Choices:
A. the grocery store
B. the library
C. the gas station
D. the fire department
Answer with the letter.
| 0A
|
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