SKIN

The largest organ in the human body, the skin, is roughly 20 square feet in size. It acts as a barrier against damage, infection, heat, and light. Three layers make up the skin:

Epidermis: The outermost layer that includes the stratum corneum, the main protective structure.
Dermis: A fibrous layer that gives the epidermis stability and vigor.

Subcutis: The layer of fat beneath the dermis that provides nourishment and acts as an insulator for the body. Moreover, skin functions as insulation, temperature regulation, sense organs, production of vitamin D, and defense.