Final answer:
Hair is an accessory structure of the skin composed of dead, keratin-filled cells. The overlapping cells of the hair shaft help shed water, similar to roof shingles. Hair follicles are the structures from which hairs grow.
Step-by-step explanation:
Hair is an accessory structure of the skin that originates from the epidermis and extends into the dermis. It is composed of dead, keratin-filled cells arranged in a shaft-like structure.
The overlapping cells of the hair shaft help shed water, similar to the shingles on a roof.
Hair follicles are the structures from which hairs grow, and they pass through the epidermis before reaching the surface of the skin.