Which hair strand layer is primarily responsible for strength and contains the pigments?

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

Answer: (B)

The cortex is the layer that provides hair with its strength and houses the pigments that give hair its color. It sits between the outer protective cuticle and the central medulla and is made of keratin-rich cells that form the fiber’s bulk, giving durability, elasticity, and structure. The pigments, or melanin, are embedded in this layer, which is why color is determined by the cortex. The outer cuticle protects the cortex but doesn’t contribute much to strength or color, and the medulla—when present—is a softer, central portion that doesn’t play a major role in strength or pigmentation. The dermis isn’t part of the hair strand at all; it’s the skin layer that surrounds the follicle.