What is hair primarily made of?

Hair is primarily made of dead epidermal cells that have undergone a process known as keratinization. During this process, the living cells in the hair follicle produce keratin, a fibrous protein that provides strength and structure to the hair shaft. By the time the hair emerges from the scalp, these cells are no longer living and have fully transitioned into keratin, making them essentially a compact bundle of keratinized cells.

This keratin is what gives hair its resilience and helps it withstand various forms of physical stress. The structure of hair is relatively simple, as it is primarily composed of keratin fibers. Hair follicles are indeed associated with living cells, but the actual visible part of the hair is not living; it is the result of these processes that convert epidermal cells to keratin.

The other choices involve components associated with hair, but they do not accurately represent the primary composition of hair itself. Living cells filled with melanin pertain more to the pigmentation of hair rather than its primary structure. Protein fibers surrounded by lipids refer to a more general concept rather than the specific makeup of hair. Dermal papilla cells are found at the base of hair follicles and are important for hair growth but do not constitute the hair itself. Thus