. Barrier against infection because pathogens block out debris and prevents the body from drying out, also protects against ultraviolet radiation, nails protect skin. .helps regulate body temperature with hair . Excretes wastes with sweat . Gathers information with sensory glands which send information to the nervous system . Produces vitamin D needed for the small intestines because it forms calcium and phosphorus

We need protective things for our body like nails to protect the skin, hair and sweat glands to help maintain a steady body temperature, and sensory glands to tell us when something is wrong.

By releasing excess heat generated by working cells, goosebumps when a person gets too cold too fast, radiation, hair, sweat, and constricting/radiating blood vessels