Answer :
A stream channel is defined as a path for water and sediment flowing within the stream banks. It is formed when water is formed when watercarves a narrow path into rock. The answer therefore to this problem is option A.
The correct answer is A. A stream channel is formed when water carves a narrow path into rock.
The action of the water on the rocks, with the passage of time, generates furrows on which the main channel develops secondary arms, called stream channels. As time passes, the erosion of the water on the rocks increases the size of these channels.
