What is the primary role of the cuticle in hair structure?

The primary role of the cuticle in hair structure is to protect the inner layers of the hair shaft. The cuticle consists of overlapping, scale-like cells that form a tough outer layer. This structure serves as a barrier against environmental damage, preventing the penetration of harmful substances and retaining moisture within the hair. By acting as this protective layer, the cuticle plays a crucial role in maintaining the overall health and integrity of the hair.

While the other choices highlight important functions associated with hair, such as elasticity, moisture regulation, and color influence, these functions are primarily related to the cortex and medulla of the hair. The cortex contains the proteins that give hair its strength and elasticity, while the medulla may play a role in moisture retention and contributes to the overall aesthetic qualities, including color. However, the cuticle's primary function is distinctly centered on protection, making it essential for the longevity and resilience of hair.