Which hair shaft component is primarily responsible for hair strength and color depth?

• A. Medulla
• B. Cortex
• C. Cuticle
• D. Follicle

Answer: (B)

Strength and color depth come from the cortex, the middle layer of the hair shaft where keratin fibers and melanin pigments reside. The cortex provides most of the hair’s structural strength and elasticity through its tightly packed keratin, while the melanin within the cortex gives the hair its color and depth. The inner medulla, when present, is not the main driver of strength or shade. The outer cuticle protects the cortex but does not determine how strong the hair is or how rich the color appears. The follicle is the skin structure that produces the hair, not a part of the shaft itself.