Root hairs are epidermal outgrowths of the outermost layer of roots. They are well suited for absorption of water from the soil due to:

P and R

Reason — Root hairs are very fine and numerous, which gives them a large surface area for absorption. The cell sap inside them is more concentrated than the soil water, so water enters by endosmosis. Q is wrong because the cell sap is more concentrated, not less, and S is wrong because the cell membrane of the root hair is semipermeable, not freely permeable.