Question

Study the images of Earth’s crust and mantle in two different areas.

Item A shows a Lava source going through the Mantle and Crust, rising above Sea level to surface labeled Hawaii. Item B shows the Mantle beginning level on the left and dipping down on the right; the Crust is level on the left, labeled Great Valley of California, with mountains on the right, labeled Sierra Nevada and Mount Whitney.

How is Item A different from Item B?

The crust under the ocean in Item A is thicker than the crust under the mountain in Item B.
The mantle under the ocean in Item A is thinner than the mantle under the mountain in Item B.
The crust in Item A is found partially below sea level as compared to the crust in Item B.
The mantle in Item A is located far below a mountain as compared to the mantle in Item B.

Answer 1

Correct answers: 2 and 3.

Brief explanations:
- 1 is false — oceanic crust (Item A) is thinner than continental crust beneath mountains (Item B), not thicker.
- 2 is true (interpreted as “the mantle lies closer to the surface under the ocean island than under the mountain”): because oceanic crust is thin, the mantle is nearer the surface in A; continental crust beneath the Sierra Nevada is thick so the mantle is deeper there.
- 3 is true — the crust in Item A is largely below sea level (oceanic crust) with only the volcanic peak above water, whereas Item B shows continental crust above sea level.
- 4 is false — the mantle is farther below the mountain in B than it is under the ocean in A (the statement reverses the situation).