Statement I: In the context of effect of water on rocks, chalk is known as a very permeable rock whereas clay is known as quite an impermeable or least permeable rock.

Statement II: Chalk is porous and hence can absorb water.

Statement III: Clay is not at all porous.

Which one of the following is correct in respect of the above statements?

(a) Both Statement II and Statement III are correct and both of them explain Statement I

(b) Both Statement II and Statement III are correct but only one of them explains Statement I

(c) Only one of the Statements II and III is correct and that explains Statement I

(d) Neither Statement II nor Statement III is correct

Ans-c

Explanation

Chalk is characterized by its high porosity and permeability, which enables it to easily absorb water. Its structure consists of numerous small pores that allow water to pass through effortlessly. On the other hand, clay possesses exceptionally fine pores that render it nearly impermeable. Although it is not entirely devoid of porosity, the minuscule size of its pores significantly restricts water flow, making it much less permeable than chalk. 

Hence, only Statement II is correct and it explains Statement I.

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