from Yellowstone National Park: Geology

Question

1 The landscape of the Greater Yellowstone Ecosystem is the result of various geological processes over the last 150 million years. Here, Earth's crust has been compressed, pulled apart, glaciated, eroded, and subjected to volcanism. All of this geologic activity formed the mountains, canyons, and plateaus that define the natural wonder that is Yellowstone National Park.

F

2 While these mountains and canyons may appear to change very little during our lifetime, they are still highly dynamic and variable. Some of Earth's most active volcanic, hydrothermal (water + heat), and earthquake systems make this national park a priceless treasure. In fact, Yellowstone was established as the world's first national park primarily because of its extraordinary geysers, hot springs, mudpots and steam vents, as well as other wonders such as the Grand Canyon of the Yellowstone River.

Part A

What does the phrase highly dynamic and variable indicate about the mountains and canyons of Yellowstone in the first sentence of paragraph 2?

1. They are extremely old features.

2. They are mainly why the park exists.

3. They are especially popular with visitors.

4. They are continually undergoing changes.

Part B

Which detail from the passage best supports the correct answer

from Part A?

1. "processes over the last 150 million years" (Paragraph 1)

2. "define the natural wonder" (Paragraph 1)

3. "active volcanic, hydrothermal (water + heat), and earthquake systems" (Paragraph 2)

4. "extraordinary geysers, hot springs, mudpots and steam vents" (Paragraph 2)

Answer 1

Part A

The correct answer is: 4. They are continually undergoing changes.

The phrase "highly dynamic and variable" indicates that the mountains and canyons of Yellowstone are not static but are consistently undergoing changes due to ongoing geological processes.

Part B

The detail from the passage that best supports the correct answer from Part A is: 3. "active volcanic, hydrothermal (water + heat), and earthquake systems" (Paragraph 2).

This detail highlights the continuous geological activity in Yellowstone, which contributes to the continual changes in its landscape.