Final answer:
The skin has multiple roles in the body, including preventing water loss, serving as a barrier to microorganisms, synthesizing vitamin D, excreting sebum, secreting water and salt through sweat, and absorbing oils or lipid-soluble substances.
Step-by-step explanation:
The skin has multiple roles in the body. Many of these roles are related to homeostasis. The skin's main functions include preventing water loss from the body and serving as a barrier to the entry of microorganisms. Another function of the skin is synthesizing vitamin D, which occurs when the skin is exposed to ultraviolet (UV) light. Melanin in the epidermis blocks some of the UV light and protects the dermis from its damaging effects.
One of the functions of the skin is the excretion of sebum that lubricates the skin surface and hair. Sweat glands in the skin also secrete water and salt during sweating, which plays a role in electrolyte homeostasis. Additionally, the skin can absorb oils or lipid-soluble chemicals or drugs, such as estrogen or nicotine, through transdermal patches.