How are plains formed?
Plains are vast pieces of flat land. Most of the plains are formed by erosional, transportation and depositional activities of rivers. Rivers erode the mountains while flowing through them. They transport the eroded sediments (small pieces of sand, stones and silt) during their course and deposit these materials in the valleys or along their course. For example, the Ganga-Brahmaputra plains have been formed as a result of erosional, transportation and depositional activities of rivers Ganga and Brahmaputra.