Which of the following is NOT a function of skin?

The statement that skin synthesizes vitamin A is not accurate; instead, the skin plays a role in synthesizing vitamin D when exposed to sunlight. The functions of the skin include acting as a barrier to infections, regulating body temperature, and storing fat.

As a barrier, the skin protects the body from pathogens and environmental hazards. It maintains homeostasis by regulating body temperature through mechanisms such as sweating and blood vessel dilation or constriction. The skin also serves as an energy reserve by storing fat in the subcutaneous layer, providing insulation and cushioning for underlying structures.

Therefore, while the skin is essential for several critical functions, synthesizing vitamin A is not one of them, making it the correct answer to the question.