Question

Root hairs arise from ______ and increase the ______ for absorption.
A. Cortex and surface area
B. Epidermis and Cambium
C. Cortex and Cambium
D. Epidermis and surface area

Answer 1

Hint: Plants take in water and minerals through the roots. Root hairs are tiny, hair-like structures that grow on the surface of the plant roots.

Complete step-by-step solution:
To solve this question, first we need to know about epidermis. The epidermis is the outer layer of plant and animal cells. The entire surface of a plant is covered by the epidermis. The epidermis protects the plants against loss of water and external injury.
Now, let us find the solution from the given options.
The cortex is the tissue present between the epidermis and the vascular tissues of a root or stem. They are composed of parenchyma cells that mainly function to store food or to transport materials.
The cambium is the layer of meristematic tissue present between phloem and xylem that is responsible for the secondary growth of roots and stems. These cells actively divide to form new tissues. The girth of the stem or root increases due to cambium. There are different types of cambium found in the stems and roots.
The root hairs absorb water and mineral solutes through diffusion. Root hairs are tiny extensions of epidermal root cells with thin cell walls. The main function of root hair is to increase the area of the surface available for water absorption and that of minerals and other nutrients.

So, option D .i.e., Epidermis and surface area is the correct answer.

Additional information:
The protective tissue on the outer surface undergoes changes as the plants mature. A secondary meristem layer replaces the stem's epidermis. It forms the tree's dense multi-layer cork, or bark. Cork cells are dead, and organized compactly without intercellular spaces.

Note: The cambium is responsible for forming secondary tissues. They are present between the vascular tissues. The vascular cambium in both shoots and roots consists of two kinds of cells: small, cuboidal ray parenchyma cells and spindle-shaped, long fusiform cells. Cortex and pith in stems and roots are commonly referred to as ground tissue. The vascular system is surrounded by the ground tissue in the stem.