Question

the plains are made up of sand,clay,silt,and calcerous gravels locally known as​

Answer 1

Explanation:

these plains are known as delta

Answer 2

ANSWER:

"The plains are made" up of "sand, clay, silt" and calcerous gravels locally known as​ Delta.

EXPLANATION:

   The biggest delta in the world is known as the Sunderban Delta which lies in the eastern part of India in Bengal and the rest in Bangladesh. Bangladesh is the home to the majority of the delta lying in the belt.

   Deltas are generally not all solid land it is built by the accumulation of everything mentioned over the years.