What is the primary function of sweat glands?

The primary function of sweat glands is to regulate body temperature. Sweat glands are an essential part of the body's thermoregulation system. When the body's temperature rises due to external heat or physical activity, sweat glands produce sweat, which is primarily composed of water and salts. As sweat evaporates from the surface of the skin, it cools the body down, helping to maintain a stable internal temperature.

This regulatory mechanism is vital for preventing overheating, which can lead to heat-related illnesses. Additionally, by releasing waste products through sweat, these glands play a minor role in excretion, but their main purpose is indeed to cool the body effectively.

The other choices involve functions that do not primarily relate to sweat glands. While oils are produced by sebaceous glands to keep the skin moisturized, protection against UV rays is primarily managed by melanin produced in the skin, and skin elasticity is contributed to by collagen and elastin, rather than any function of sweat glands.