Compare and contrast the features of a river near its source and far down along its course.

The river bed upstream of a river is V-shaped while downstream is U-shaped. This is because the speed at the watershed of the river is higher because of the higher inclination due to mountains in the region. The vertical erosion of the waters in higher than the horizontal erosion. Close to the mouth of the river, due to low speeds, the horizontal erosion is greater than vertical erosion.This is why Ox-bow lakes and deltas form downstream of the rivers while rapids and cataracts are found upstream of a river

Near its source, a river is fast moving and flows on a steep mountain slope. It rapidly erodes a V-shaped, steep-sided valley. ... Farther along its course, a river flows over gently sloping land.

the answer is c. nacl