What is one major function of the skin?

The skin serves as a vital barrier that protects the body in multiple ways, making protection against body fluid loss and microorganisms one of its major functions. This protective function is crucial for maintaining homeostasis—the balance of bodily fluids—and preventing pathogens from entering the body. The outermost layer of the skin, known as the epidermis, provides a physical barrier and contains keratin, which helps to prevent water loss. Additionally, the skin plays an important role in the immune response; it houses immune cells that detect and respond to microbial intrusions, thereby reducing the risk of infection.

Other functions of the skin, such as thermoregulation and sensory perception, are also important, but the protective role is particularly significant as it directly contributes to overall health and safety of the organism. The other options do not accurately represent the primary functions of the skin.