D. Answer the following questions in brief. D1. Specify two differences between internal and external forces Ans: Internal forces: (i) Internal forces are those which have been generating deep inside of the Earth surface. (ii) These forces are responsible to form major relief of the Earth like mountains, volcanoes, Plateau, Tectonic plate etc External Forces: (i) External forces are those which act on the surface of the earth causing a change in the nature and shape of a landform. For example, wind and water are the external forces which cause weathering and denudation of land. (ii) These forces are modifying the shapes of the landform formed by the impact of internal forces D2. Name the various agents of gradation. Ans: Four agents of gradation are rivers, winds, sea water and glaciers. D3. Distinguish between transported and residual soil. Ans: Soils which are carried away by water, wind, etc., and later get deposited at a new pl...