(i) Biological weathering is also known as organic weathering because it is the disintegration of rocks as a result of the action by living organisms.
(ii) Vegetation prevents disintegration of rocks because it binds the surface layer and does not allow exposure of rocks beneath to the elements of weathering.
(iii) Chemical and biological weathering is negligible in polar climates because water is in frozen state in the polar regions and most living organisms cannot survive in such cold climatic conditions.