Final answer:
The skin does not synthesize vitamin A; it synthesizes vitamin D. It also protects against environmental threats, prevents dehydration, senses environmental stimuli, and regulates body temperature. The correct option is A.
Step-by-step explanation:
The function of the skin that is NOT correctly described is acts as a gland by synthesizing vitamin A. The skin, in fact, synthesizes vitamin D, not vitamin A, when it is exposed to ultraviolet (UV) light.
The skin has several other critical roles such as protection against environmental hazards, preventing dehydration, acting as a sensory organ for detecting touch, pressure, pain, and temperature, and thermoregulation.
The skin contains sweat glands and sebaceous glands that help regulate body temperature and maintain homeostasis by excreting water, salt, and small amounts of waste. Furthermore, melanin in the skin provides protection against UV radiation.