The major function of root hairs on roots is to

• A. Store starch
• B. Anchor the plant
• C. Absorb water and minerals from the soil
• D. Photosynthesize

Answer: (C)

Root hairs primarily increase the root’s surface area so the plant can efficiently take up water and nutrients from the soil. These tiny extensions of epidermal cells reach into the moist soil solution, exposing more membrane to dissolved minerals and water. Water moves into the root by osmosis along a water potential gradient, and minerals enter via transport proteins that use energy to move ions into the cells. Starch storage happens in other root tissues, not in root hairs. While root hairs help the root system interact with the soil, anchoring is achieved by the overall structure of the roots rather than by the hairs themselves. Roots also don’t photosynthesize because they are usually underground and lack chlorophyll-containing tissues. So the key role of root hairs is absorbing water and minerals from the soil.