examples21

id: 11786

lecture: Measurements are written with both a number and a unit. The unit comes after the number. The unit shows what the number means. When you are using metric units, length can be written with units of millimeters, centimeters, meters, or kilometers. One meter contains 100 centimeters or 1,000 millimeters. So, 1 meter is larger than 1 centimeter, and 1 centimeter is larger than 1 millimeter. The tip of the pencil shown here is only 1 millimeter wide, but the pencil is about 16 centimeters long. A red fox is about 1 meter long. The Sydney Harbour Bridge in Australia is about 1,000 meters, or 1 kilometer, in length.

question: How long is a caterpillar?

choice: (A) 17 centimeters (B) 17 meters (C) 17 kilometers (D) 17 millimeters

context: Select the best estimate.

answer: D

Rationale:

0: Measurements are written with both a number and a unit.
1: The unit comes after the number.
2: The unit shows what the number means.
3: When you are using metric units, length can be written with units of millimeters, centimeters, meters, or kilometers.
4: One meter contains 100 centimeters or 1,000 millimeters.
5: So, 1 meter is larger than 1 centimeter, and 1 centimeter is larger than 1 millimeter.
6: The tip of the pencil shown here is only 1 millimeter wide, but the pencil is about 16 centimeters long.
7: A red fox is about 1 meter long.
8: The Sydney Harbour Bridge in Australia is about 1,000 meters, or 1 kilometer, in length.
9: The best estimate for the length of a caterpillar is 17 centimeters.
10: 17 millimeters is too short.
11: 17 meters and 17 kilometers are too long.
12: The answer is A.

generated_skill:

solution: The best estimate for the length of a caterpillar is 17 millimeters. 17 centimeters, 17 meters, and 17 kilometers are all too long.

skill: Choose metric units of distance, mass, and volume

wrong_step_idx: 0

id: 12120

lecture: 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.

question: Which word would you find on a dictionary page with the following guide words? igloo - injury

choice: (A) itch (B) impose

context: N/A

answer: B

Rationale:

0: Guide words appear on each page of a dictionary.
1: They tell you the first word and last word on the page.
2: The other words on the page come between the guide words in alphabetical order.
3: To put words in alphabetical order, put them in order by their first letters.
4: If the first letters are the same, look at the second letters.
5: If the second letters are the same, look at the third letters, and so on.
6: If one word is shorter, and there are no more letters to compare, then the shorter word comes first in alphabetical order.
7: For example, be comes before bed.
8: Put the words in alphabetical order.
9: Since itch is between the guide words igloo - injury, it would be found on that page.
10: The answer is A.

generated_skill:

solution: Put the words in alphabetical order. Since impose is between the guide words igloo - injury, it would be found on that page.

skill: Use guide words

wrong_step_idx: 0

id: 12158

lecture: When writing, make sure to avoid vague pronoun references. A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent. When Lisa and Kim finally landed, she breathed a sigh of relief. The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear. Vague pronoun references can be corrected in one of two ways: 1. Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief. 2. Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed. A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent. They say that this nail polish dries in less than five minutes. The pronoun they is used without its antecedent, so the meaning of the sentence is unclear. This problem can be fixed by replacing the pronoun with its missing antecedent. The advertisements say that this nail polish dries in less than five minutes.

question: Which of the following contains a vague pronoun reference?

choice: (A) When Molly ran into Maria at the post office, she smiled and said hello. (B) Molly smiled and said hello when she ran into Maria at the post office.

context: N/A

answer: A

Rationale:

0: When writing, make sure to avoid vague pronoun references.
1: A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent.
2: When Lisa and Kim finally landed, she breathed a sigh of relief.
3: The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear.
4: Vague pronoun references can be corrected in one of two ways: 1.
5: Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief.
6: 2.
7: Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed.
8: A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent.
9: They say that this nail polish dries in less than five minutes.
10: The pronoun they is used without its antecedent, so the meaning of the sentence is unclear.
11: This problem can be fixed by replacing the pronoun with its missing antecedent.
12: The advertisements say that this nail polish dries in less than five minutes.
13: The second answer choice contains a vague pronoun reference.
14: The pronoun she could refer to Molly or Maria.
15: Molly smiled and said hello when she ran into Maria at the post office.
16: The first answer choice shows a possible correction for the vague pronoun reference.
17: The text has been rewritten so that the meaning is clear.
18: When Molly ran into Maria at the post office, she smiled and said hello.
19: The answer is B.

generated_skill:

solution: The first answer choice contains a vague pronoun reference. The pronoun she could refer to Molly or Maria. When Molly ran into Maria at the post office, she smiled and said hello. The second answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear. Molly smiled and said hello when she ran into Maria at the post office.

skill: Identify vague pronoun references

wrong_step_idx: 0

id: 12181

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 three objects have in common?

choice: (A) soft (B) opaque (C) flexible

context: Select the best answer.

answer: B

Rationale:

0: An object has different properties.
1: A property of an object can tell you how it looks, feels, tastes, or smells.
2: Properties can also tell you how an object will behave when something happens to it.
3: Different objects can have properties in common.
4: You can use these properties to put objects into groups.
5: Grouping objects by their properties is called classification.
6: Look at each object.
7: For each object, decide if it has that property.
8: A soft object changes shape when pressed or squeezed.
9: All three objects are soft.
10: An opaque object does not let light through.
11: The grocery bag is opaque, but the tissue and the clay are not.
12: A flexible object can be folded or bent without breaking easily.
13: The tissue is flexible, but the grocery bag is not.
14: The property that all three objects have in common is soft.
15: The answer is A.

generated_skill:

solution: 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 paper notebook and the grocery bag are flexible, but the concrete steps are not. A soft object changes shape when pressed or squeezed. The concrete steps are not soft. An opaque object does not let light through. All three objects are opaque. The property that all three objects have in common is opaque.

skill: Compare properties of objects

wrong_step_idx: 0

id: 12223

question: Which of the following contains a vague pronoun reference?

choice: (A) Just as Mrs. Bradley finished brewing Jane a cup of tea, her phone rang. (B) Mrs. Bradley's phone rang just as she finished brewing Jane a cup of tea.

context: N/A

answer: A

Rationale:

0: When writing, make sure to avoid vague pronoun references.
1: A vague pronoun reference occurs when a pronoun could refer to more than one possible antecedent.
2: When Lisa and Kim finally landed, she breathed a sigh of relief.
3: The pronoun she could refer to either Lisa or Kim, so the meaning of the sentence is unclear.
4: Vague pronoun references can be corrected in one of two ways: 1.
5: Replace the pronoun with its correct antecedent: When Lisa and Kim finally landed, Lisa breathed a sigh of relief.
6: 2.
7: Rewrite the sentence: Lisa breathed a sigh of relief when she and Kim finally landed.
8: A vague pronoun reference also occurs when they, them, their, theirs, it, or its is used without its antecedent.
9: They say that this nail polish dries in less than five minutes.
10: The pronoun they is used without its antecedent, so the meaning of the sentence is unclear.
11: This problem can be fixed by replacing the pronoun with its missing antecedent.
12: The advertisements say that this nail polish dries in less than five minutes.
13: The second answer choice contains a vague pronoun reference.
14: The pronoun her could refer to Mrs. Bradley's or Jane's.
15: Mrs. Bradley's phone rang just as she finished brewing Jane a cup of tea.
16: The first answer choice shows a possible correction for the vague pronoun reference.
17: The text has been rewritten so that the meaning is clear.
18: Just as Mrs. Bradley finished brewing Jane a cup of tea, her phone rang.
19: The answer is B.

generated_skill:

solution: The second answer choice contains a vague pronoun reference. The pronoun her could refer to Mrs. Bradley's or Jane's. Just as Mrs. Bradley finished brewing Jane a cup of tea, her phone rang. The first answer choice shows a possible correction for the vague pronoun reference. The text has been rewritten so that the meaning is clear. Mrs. Bradley's phone rang just as she finished brewing Jane a cup of tea.

skill: Identify vague pronoun references

wrong_step_idx: 0

id: 12252

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 yellow particles?

choice: (A) Solution A (B) Solution B (C) neither; their concentrations are the same

context: The diagram below is a model of two solutions. Each yellow ball represents one particle of solute.

answer: A

Rationale:

0: A solution is made up of two or more substances that are completely mixed.
1: In a solution, solute particles are mixed into a solvent.
2: The solute cannot be separated from the solvent by a filter.
3: 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.
4: In this case, the salt is the solute.
5: The water is the solvent.
6: The concentration of a solute in a solution is a measure of the ratio of solute to solvent.
7: Concentration can be described in terms of particles of solute per volume of solvent.
8: concentration = particles of solute / volume of solvent In Solution A and Solution B, the yellow particles represent the solute.
9: 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.
10: Use the concentration formula to find the number of yellow particles per milliliter.
11: Solution A and Solution B have the same number of yellow particles per milliliter.
12: So, their concentrations are the same.
13: The answer is C.

generated_skill:

solution: 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.

skill: Compare concentrations of solutions

wrong_step_idx: 0

id: 12296

lecture: A food web is a model. A food web shows where organisms in an ecosystem get their food. Models can make things in nature easier to understand because models can represent complex things in a simpler way. If a food web showed every organism in an ecosystem, the food web would be hard to understand. So, each food web shows how some organisms in an ecosystem can get their food. Arrows show how matter moves. A food web has arrows that point from one organism to another. Each arrow shows the direction that matter moves when one organism eats another organism. An arrow starts from the organism that is eaten. The arrow points to the organism that is doing the eating. An organism in a food web can have more than one arrow pointing from it. This shows that the organism is eaten by more than one other organism in the food web. An organism in a food web can also have more than one arrow pointing to it. This shows that the organism eats more than one other organism in the food web.

question: Which of these organisms contains matter that was once part of the bear sedge?

choice: (A) grizzly bear (B) bilberry (C) short-tailed weasel

context: Below is a food web from a tundra ecosystem in Nunavut, a territory in Northern Canada. A food web models how the matter eaten by organisms moves through an ecosystem. The arrows in a food web represent how matter moves between organisms in an ecosystem.

answer: C

Rationale:

0: A food web is a model.
1: A food web shows where organisms in an ecosystem get their food.
2: Models can make things in nature easier to understand because models can represent complex things in a simpler way.
3: If a food web showed every organism in an ecosystem, the food web would be hard to understand.
4: So, each food web shows how some organisms in an ecosystem can get their food.
5: Arrows show how matter moves.
6: A food web has arrows that point from one organism to another.
7: Each arrow shows the direction that matter moves when one organism eats another organism.
8: An arrow starts from the organism that is eaten.
9: The arrow points to the organism that is doing the eating.
10: An organism in a food web can have more than one arrow pointing from it.
11: This shows that the organism is eaten by more than one other organism in the food web.
12: An organism in a food web can also have more than one arrow pointing to it.
13: This shows that the organism eats more than one other organism in the food web.
14: Use the arrows to follow how matter moves through this food web.
15: For each answer choice, try to find a path of arrows that starts from the bear sedge.There are two paths matter can take from the bear sedge to the grizzly bear: bear sedge->grizzly bear.
16: bear sedge->mushroom->grizzly bear.
17: There are two paths matter can take from the bear sedge to the short-tailed weasel: bear sedge->short-tailed weasel.
18: bear sedge->mushroom->short-tailed weasel.
19: There is one path matter can take from the bear sedge to the bilberry: bear sedge->bilberry.
20: The answer is A.

generated_skill:

solution: Use the arrows to follow how matter moves through this food web. For each answer choice, try to find a path of arrows that starts from the bear sedge. The grizzly bear has two arrows pointing to it. One arrow starts from the bilberry. The bilberry does not have any arrows pointing to it. The other arrow pointing to the grizzly bear starts from the barren-ground caribou. The only arrow pointing to the barren-ground caribou starts from the lichen. The lichen does not have any arrows pointing to it. So, in this food web, matter does not move from the bear sedge to the grizzly bear. The bilberry does not have any arrows pointing to it. So, in this food web, matter does not move from the bear sedge to the bilberry.There is one path matter can take from the bear sedge to the short-tailed weasel: bear sedge->brown lemming->short-tailed weasel. There is one path matter can take from the bear sedge to the Arctic fox: bear sedge->brown lemming->Arctic fox. There is one path matter can take from the bear sedge to the rough-legged hawk: bear sedge->brown lemming->parasitic jaeger->rough-legged hawk.

skill: Interpret food webs II

wrong_step_idx: 0

id: 12326

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, 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.

question: Will these magnets attract or repel each other?

choice: (A) repel (B) attract

context: Two magnets are placed as shown. Hint: Magnets that attract pull together. Magnets that repel push apart.

answer: A

Rationale:

0: Magnets can pull or push on each other without touching.
1: When magnets attract, they pull together.
2: When magnets repel, they push apart.
3: Whether a magnet attracts or repels other magnets depends on the positions of its poles, or ends.
4: Every magnet has two poles, called north and south.
5: Here are some examples of magnets.
6: 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.
7: The magnets in the pair below attract.
8: If the same poles are closest to each other, the magnets repel.
9: The magnets in both pairs below repel.
10: Will these magnets attract or repel?
11: To find out, look at which poles are closest to each other.
12: The north pole of one magnet is closest to the south pole of the other magnet.
13: Poles that are different attract.
14: So, these magnets will attract each other.
15: The answer is B.

generated_skill:

solution: Will these magnets attract or repel? To find out, look at which poles are closest to each other. The south pole of one magnet is closest to the south pole of the other magnet. Poles that are the same repel. So, these magnets will repel each other.

skill: Identify magnets that attract or repel

wrong_step_idx: 0

id: 12349

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?

choice: (A) sample B (B) sample A (C) neither; the samples have the same temperature

context: 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.

answer: C

Rationale:

0: The temperature of a substance depends on the average kinetic energy of the particles in the substance.
1: The higher the average kinetic energy of the particles, the higher the temperature of the substance.
2: The kinetic energy of a particle is determined by its mass and speed.
3: 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.
4: Each particle in the two samples has the same mass, but the particles in sample A have a higher average speed than the particles in sample B.
5: So, the particles in sample A have a higher average kinetic energy than the particles in sample B.
6: Because the particles in sample A have the higher average kinetic energy, sample A must have the higher temperature.
7: The answer is B.

generated_skill:

solution: Each particle in the two samples has the same mass, and the particles in both samples have the same average speed. So, the particles in both samples have the same average kinetic energy. Because the particles in both samples have the same average kinetic energy, the samples must have the same temperature.

skill: Identify how particle motion affects temperature and pressure

wrong_step_idx: 0

id: 12369

question: Which solution has a higher concentration of pink particles?

choice: (A) Solution B (B) Solution A (C) neither; their concentrations are the same

context: The diagram below is a model of two solutions. Each pink ball represents one particle of solute.

answer: A

Rationale:

0: A solution is made up of two or more substances that are completely mixed.
1: In a solution, solute particles are mixed into a solvent.
2: The solute cannot be separated from the solvent by a filter.
3: 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.
4: In this case, the salt is the solute.
5: The water is the solvent.
6: The concentration of a solute in a solution is a measure of the ratio of solute to solvent.
7: Concentration can be described in terms of particles of solute per volume of solvent.
8: concentration = particles of solute / volume of solvent In Solution A and Solution B, the pink particles represent the solute.
9: To figure out which solution has a higher concentration of pink particles, look at both the number of pink particles and the volume of the solvent in each container.
10: Use the concentration formula to find the number of pink particles per milliliter.
11: Solution A has more pink particles per milliliter.
12: So, Solution A has a higher concentration of pink particles.
13: The answer is B.

generated_skill:

solution: In Solution A and Solution B, the pink particles represent the solute. To figure out which solution has a higher concentration of pink particles, look at both the number of pink particles and the volume of the solvent in each container. Use the concentration formula to find the number of pink particles per milliliter. Solution B has more pink particles per milliliter. So, Solution B has a higher concentration of pink particles.

skill: Compare concentrations of solutions

wrong_step_idx: 0