Which system serves as a protective coating and helps regulate the body's temperature?

The integumentary system is responsible for serving as a protective coating for the body and plays a crucial role in regulating body temperature. This system includes the skin, hair, nails, and various glands.

The skin acts as a barrier that protects internal organs from pathogens, UV radiation, and physical injury. It also helps the body maintain homeostasis through thermoregulation. When the body temperature rises, the sweat glands in the skin produce sweat, which evaporates and cools the body. Conversely, when it's cold, blood vessels in the skin constrict to conserve heat.

In contrast, the muscular system primarily enables movement and supports the body but does not directly protect or regulate temperature. The digestive system is essential for breaking down food and absorbing nutrients, while the lymphatic system is involved in immune response and fluid balance, but does not function as a protective coating or temperature regulator.