Question

compare the grassland region of india with that of prairies

Answer 1

Difference between grassland and prairie is that grassland is an area dominated by grass or grasslike vegetation while prairie is an extensive area of relatively flat grassland with few, if any, trees, especially in north america.

However, Prairies can also be Plains; but a Prairie and a Grassland are different. I assume that, by "Plain", they actually mean "any plain that isn't a grassland."