Question

A delta is a formation built up by?

Answer 1

Delta is build up by continuous deposition of sediments, which makes the water shallow, causing the landform to rise above the sea level. A delta is divided into four parts, i.e. subaqueous, subaerial, lower delta plain, upper delta plain.

Step-by-step explanation:

Answer 2

A river delta is a landform created by deposition of sediment that is carried by a river as the flow leaves its mouth and enters slower-moving or stagnant water. This occurs where a river enters an ocean, sea, estuary, lake, reservoir, or (more rarely) another river that cannot carry away the supplied sediment.