What is the primary function of root hairs in a tree?

Root hairs play a crucial role in the tree's survival by significantly increasing the surface area of the root system. This enhancement allows the tree to efficiently absorb water and essential nutrients from the soil. Unlike the main roots, which are thicker and less numerous, root hairs are fine, hair-like extensions that penetrate the soil very closely, maximizing contact with soil particles. This close association helps the tree to access moisture and nutrients that are vital for its growth and overall health.

The other functions cited in the options, such as food storage, structural support, or conducting photosynthesis, are performed by different parts of the tree. For instance, storage is primarily carried out in the roots or trunk; structural support is provided by the trunk and larger roots; and photosynthesis occurs in the leaves. Thus, the primary function of root hairs distinctly aligns with the absorption of water and nutrients, making it a vital aspect of tree physiology.