ICSE Class 7 Answered

A river is said to be not only an agent of erosion but also an agent of deposition due to the following reasons:

1. In the upper course, a river flows through a mountainous region. It flows steeply and hence it cuts down rocks resulting in the formation of narrow valleys. Here it erodes pieces of rocks.
2. In the middle course, a river enters a plain region. Here it slows down and the volume of the water increases. The sediments (fine pieces of rocks) get deposited here and result in the creation of different landforms like flood plains, alluvial fan etc.