Question

If a land surface where a mountain once stood is now a low, flat plain, ______ have been at work.

A) Erosion and sedimentation.
B) Volcanic eruptions.
C) Tectonic plate movement.
D) Glaciers and ice.

Answer 1

The correct answer is A) Erosion and sedimentation. Once a mountain range is formed by upthrusting of the crust, its rocks are subject to erosion by water and ice, resulting in the sharp peaks and serrated edges of mountains.

Step-by-step explanation:

If a land surface where a mountain once stood is now a low, flat plain, the correct answer would be A) Erosion and sedimentation. Once a mountain range is formed by upthrusting of the crust, its rocks are subject to erosion by water and ice. The sharp peaks and serrated edges of mountains result from the processes that tear down mountains, including erosion by water and ice.