Why do plant roots have so many root hairs?

Answer 1

Root hairs form an important surface over which plants absorb most of their water and nutrients. The cell structure of root hairs exhibits a large surface area to volume ratio. This is an important evolutionary function that enables a large amount of water and mineral absorption into the organism without wasting valuable energy. Root hairs are highly specialized cells necessary for a vascular plant's ability to maintain its survival.

A root hair is a tubular outgrowth of root epidermal cells of vascular plants. They are found only in the region of maturation of the root. Root hairs are a specialized form of rhizoid.
In other words...

A root hair is a tubular outgrowth of root epidermal cells of vascular plants. They are found only in the region of maturation of the root. Root hairs are a specialized form of rhizoid.

Root hairs form an important surface over which plants absorb most of their water and nutrients. They are also directly involved in the formation of root nodules in legume plants.

They have a large surface area, relative to the other cells, that help them absorb water and minerals more efficiently.

Root hairs are usually an outgrowth of a single epidermal cell that grow out of the roots. In other words, they are one cell thick, and therefore very fragile. This is why if you pull a plant out of the ground even with its visible roots still attached, the plant will often die when replanted. It needs the root hairs' extra surface area. :-D

Answer 2

To increase the surface area of absorption used for providing the Plant with Water;

and they also provide a larger surface area for anchorage.

They are used to absorb water and to give Plants access to this Water.

Answer 3

to increase the surface area of absorption for the plant

Answer 4

Plants have so many root hairs to help them anchor the plant to the ground

Edited answer:

So many root hairs in plant roots are given out to absorb more and more water.

Answer 5

to protect itself