Main Idea
What are two main ideas in the article? Select the two sentences that best describe the main ideas in the article.
A. The heavy boulders at Racetrack Playa move over long distances.
B. Many ideas have been offered to explain the movement of the Racetrack Playa stones.
C. Racetrack Playa, found in California, becomes icy during wet winters.
D. Video cameras helped scientists understand what was happening at Racetrack Playa.
E. Scientists now know why the rocks at Racetrack Playa move.
B and E: These choices capture the key focus of the passage—how the mystery of the moving stones puzzled scientists for years and how they eventually discovered the explanation.
How did Richard Norris and Jim Norris know when the rocks started to move?
A. Video cameras kept constant watch on the rocks.
B. The weather station showed when winds were strong enough to shift rocks.
C. The rocks began to leave tracks by shifting on the surface of the playa.
D. Any motion of the rocks triggered the GPS system.
D. Any motion of the rocks triggered the GPS system.
What is one effect of the sailing stones' movement?
A. They leave behind trails in the desert surface
B. They eventually sink into the soft mud
C. They disappear into the sand over time
D. They change shape as they move
A. They leave behind trails in the desert surface
What is the meaning of the word "trail" as used in the passage?
A. A group of people walking together
B. A path left behind by something moving
C. A difficult journey through rough terrain
D. A type of desert plant
B. A path left behind by something moving.
Which multiple-choice answer could be eliminated first when answering this question?
What is the primary cause of the sailing stones' movement?
A. Strong winds blowing across the desert
B. Earthquakes shaking the ground
C. A combination of ice, wind, and water creating ideal conditions
D. Magnetic forces pulling the rocks
D. Magnetic forces pulling the rocks. Magnetism wasn't mentioned as a factor in the stones' movement.
What is the main function of paragraph 4?
A. To explain the role of wind in moving the rocks
B. To propose wet weather is responsible for rock movements
C. To indicate earlier ideas about rock movements were mistaken
D. To provide an example of an incorrect theory of how the rocks move
C. To indicate earlier ideas about rock movements were mistaken.
Paragraph 4 likely discusses past theories that were incorrect, helping to show how scientific understanding has evolved over time.
In paragraph 6, what does the author mean by the phrase “a unique combination of events”?
A. The combination happens in the cold.
B. The combination lasts a long time.
C. The combination rarely happens.
D. The combination is clear to see.
C. The combination rarely happens.
What is the primary cause of the sailing stones' movement?
A. Strong winds blowing across the desert
B. Earthquakes shaking the ground
C. A combination of ice, wind, and water creating ideal conditions
D. Magnetic forces pulling the rocks
C. A combination of ice, wind, and water creating ideal conditions
What does the word "movement" refer to in the passage?
A. The act of staying still
B. The process of changing position or location
C. A group of people working toward a goal
D. A type of wind pattern
B. The process of changing position or location.
Which answer choice is least likely to be correct and could be eliminated first?
What is the effect of the sailing stones' movement?
A. They leave behind trails in the desert surface
B. They disappear into the sand over time
C. They change shape as they move
D. They eventually sink into the soft mud
C. (They change shape as they move) could be eliminated first because the passage does not indicate that the stones physically change shape while moving.
What do scientists now understand about the movement of the stones?
A. They have no idea how the stones move.
B. The stones move due to gravity alone.
C. A combination of ice and wind causes the movement.
D. They are pushed by animals.
C. A combination of ice and wind causes the movement.
What evidence does the author give to support the point that the theory involving gravity was incorrect?
A. The playa has a slope.
B. Some rocks move uphill.
C. Ice forms on the bottom of some rocks.
D. The surface of the playa can become slippery.
B. Some rocks move uphill.
What effect does the presence of ice have on the movement of the stones?
A. It causes the stones to sink into the ground
B. It allows the stones to slide more easily when pushed by the wind
C. It keeps the stones from moving by freezing them in place
D. It increases the weight of the stones, making them harder to move
B. It allows the stones to slide more easily when pushed by the wind.
Which definition best fits the word "conditions" in the passage?
A. Rules that must be followed
B. The state of the environment at a particular time
C. A type of rock formation
D. A scientific experiment
B. The state of the environment at a particular time.
Which answer choice could be eliminated first when answering this question?
What does the word "exposed" mean in the sentence: "Only certain stones are exposed to the right combination of wind and ice"?
A. Covered completely
B. Left unprotected or open to something
C. Hidden beneath the surface
D. Removed from an area
Choice A (Covered completely) could be eliminated first because "exposed" suggests being open to something, not covered.
How long did it take for scientists to figure out the mystery of the sailing stones?
A. A few weeks
B. Several years
C. Just a few days
D. Many decades
D. Many decades
Scientists spent decades studying the sailing stones, proposing various theories before finally confirming that a combination of ice, wind, and water was responsible for their movement.
How did the Norris cousins resolve the mystery of the sailing stones?
A. By observing the event as it occurred
B. By reasoning backward from evidence of the event
C. By eliminating other possible reasons for the event
D. By establishing what the conditions were prior to the event
B. By reasoning backward from evidence of the event. The Norris cousins were able to solve the mystery of the "sailing stones" by analyzing the evidence left behind, such as the trails the rocks left on the surface of the playa. They used this information, along with data from their GPS system and weather conditions, to deduce the chain of events that led to the stones' movement.
Why do some stones move while others remain stationary?
A. Some stones are heavier than others
B. Only certain stones are exposed to the right combination of wind and ice
C. Some stones are magnetic and others are not
D. The ground beneath some stones is softer
B. Only certain stones are exposed to the right combination of wind and ice.
What does the word "exposed" mean in the sentence: "Only certain stones are exposed to the right combination of wind and ice"?
A. Covered completely
B. Left unprotected or open to something
C. Hidden beneath the surface
D. Removed from an area
B. Left unprotected or open to something
Which multiple-choice answer could be eliminated first when answering this question?
What was the effect of scientists placing GPS trackers on the stones?
A. They discovered the stones moved due to underground currents
B. They were able to prove that wind alone caused the movement
C. They gathered evidence that ice sheets and wind combined to move the stones
D. The stones stopped moving because they were being monitored
Choice D (The stones stopped moving because they were being monitored) could be eliminated first because there is no logical reason why GPS trackers would prevent the stones from moving.
Why is Racetrack Playa considered unique?
A. It is located in a desert.
B. It has moving stones.
C. It is the coldest place on Earth.
D. It has the most rainfall.
B. It has moving stones.
In paragraph 6, the author says the ice sheets were “like icy bulldozers” to emphasize which quality?
A. Force
B. Smoothness
C. Speed
D. Temperature
A. Force: By comparing the ice sheets to "icy bulldozers," the author emphasizes the force and power of the ice in pushing the rocks across the playa. This imagery suggests that the ice sheets move with significant strength, helping to shift the rocks.
What was the effect of scientists placing GPS trackers on the stones?
A. They discovered the stones moved due to underground currents
B. They were able to prove that wind alone caused the movement
C. They gathered evidence that ice sheets and wind combined to move the stones
D. The stones stopped moving because they were being monitored
C. They gathered evidence that ice sheets and wind combined to move the stones.
What is the most accurate meaning of "evidence" as used in the passage?
A. Information used to support a conclusion
B. A guess or an assumption
C. A piece of rock found in the desert
D. A type of scientific tool
A. Information used to support a conclusion
What should you do before selecting an answer on a comprehension question?
A. Choose quickly so you have time for other questions
B. Read the question carefully and underline key words before looking at the choices
C. Avoid going back to the passage since that wastes time
D. Eliminate the longest answer choices first
B. Read the question carefully and underline key words before looking at the choices.