Final answer:
Hair grows from hair follicles located within the dermis layer of the skin, which contains tough connective tissue and various other structures like sweat and oil glands.
Step-by-step explanation:
Hair grows within the dermis, the layer of skin directly under the epidermis. The dermis is composed of tough connective tissue and contains various embedded structures, including hair follicles, sweat glands, sebaceous (oil) glands, and blood vessels. Each hair follicle is associated with a sebaceous gland that secretes sebum to coat and waterproof the hair, as well as a tiny muscle called arrector pili. Although hair penetrates the epidermis to exit at the surface of the skin, its growth originates deep within the dermis.