Which are the three main parts of a hair strand?

• A. Cuticle, cortex, and medulla
• B. Root, shaft, tip
• C. Keratin, melanin, collagen
• D. Epidermis, dermis, follicle

Answer: (A)

Hair strand anatomy is defined by its three-layer structure: the cuticle, cortex, and medulla. The cuticle is the outer protective layer made of overlapping scale-like cells that shield the inner layers and help seal in moisture. Beneath it, the cortex is the thick, middle layer where most of the hair’s strength, elasticity, and color originate from the keratin fibers and melanin pigment. The medulla sits at the center and may be hollow or filled with keratin; not every hair has a medulla, especially the finer types. The other options describe either external hair parts, substances associated with hair, or surrounding skin structures, but they do not identify the actual internal layering of the hair strand.