What is the primary function of hair?

The primary function of hair is to provide protection and thermal insulation. Hair serves as a barrier against environmental elements, such as UV radiation, wind, and temperature extremes. The presence of hair on the body helps to trap air close to the skin, which can aid in retaining body heat and providing warmth. This insulation is particularly important for maintaining a stable body temperature and protecting vital organs. Additionally, hair can also act as a cushion, protecting the skin from minor abrasions and injuries.

Hair does not play a significant role in coloring the skin; that function is primarily attributed to melanin, which is produced by melanocytes in the skin. While skin elasticity is important for overall skin health, this is not a function of hair. Lastly, while vitamins can affect hair growth and health, hair itself does not produce vitamins; rather, vitamins are sourced through nutrition and play roles in maintaining healthy hair and skin. Thus, the correct answer emphasizes the protective and thermal functions of hair, highlighting its essential role in overall body physiology.