Question

Why most of the rivers form distributaries before flowing into the sea?

Answer 1

because when the rivers enter into the sea the area and amount of water is large and they distributed into many delts.

Answer 2

Answer:

Most of the rivers form "distributaries" before flowing into the sea because the "river deposits sediments" at the "mouth". As the river is about to join the sea it carries a "large amount of sediments". Plus, the land where river meets the sea is gentle so the sediments settle there  As the merger is about to happen, the speed of the river decreases and since the speed is slow, so it can't carry much weight which it leaves at the "mouth of the sea".