Question

1. why does a river drop most sediment when it reaches a flat plain or the ocean? the riverbed becomes rockier and forces sediment to stick. the slope flattens, slowing the river and reducing its ability to carry sediment. the river speed increases, causing sediment to fall out. the water becomes warmer and dissolves the sediment.

Explanation:

When a river reaches a flat plain or the ocean, its slope flattens. As a result, the river's speed decreases. The ability of a river to carry sediment is related to its velocity. When the speed slows down, the river has less energy to transport sediment, so it drops most of it.

Answer:

The slope flattens, slowing the river and reducing its ability to carry sediment.