Question

how were the northern plains formed

Answer 1

northern plains were formed by the interplay of three major river system that are , Indus river system , ganga river system and Brahmaputra river system.

Answer 2

the northern plains were formed by deposits brought in by the three major rivers and their tributaries aluminium was deposited at the foothills of the Himalayas for millions of years. these deposits are the fertile northern plains Aluminium is soil or sediments deposited by a river or running water