Question

The town of Alpine Glen lies at the base of a mountain and next to the Alpine River. In recent months, the people of the town have noticed that the river has become much muddier, and that silt deposits have been building up along the river banks. Which of the following changes to the environment is the most likely cause of the change to the Alpine River?
A. Trees were cleared from a mountainside, causing an increase in soil erosion. B. Cattle or other livestock were introduced to the mountain, causing an increase in soil erosion.
C. A new dam began operating on the river, causing soil to be added to the water.
D. A new power plant increased the river temperature, causing the erosive force of the water to increase.

Answer 1

Answer:

Option A, Trees were cleared from a mountainside, causing an increase in soil erosion

Explanation:

The reason behind Alpine river getting muddier is that the surface runoff from the near by catchment areas consist of increased content of soil, clay, silt and debris.

This is possible only when the soil in the surrounding regions is loose enough to be carried away by water. And this is possible only when the trees in the near by areas are cut at a fast rate thereby leaving loose soil behind.

This loose soil is carried by water which drains into Alpine river and thus makes it muddier

Hence, option A is correct

Answer 2

The answer is A because since the trees are being cut the soil runs off to the river banks