Question

where is light penetration in a river or stream likely to be lowest? a. the source b. the mouth c. the middle portion d. none of the above please select the best answer from the choices provided

Explanation:

At the source of a river or stream, the water is often shallower and clearer, allowing more light penetration. In the middle portion, light can still reach a reasonable depth. At the mouth, there is often more sediment, turbidity, and organic matter from the entire river - system input, which reduces light penetration.

Answer:

B. the mouth