What layer of hair is a single layer of clear cells on the surface?

The correct answer is the cuticle. The cuticle is indeed the outermost layer of the hair shaft and consists of a single layer of flat, transparent cells that overlap each other, resembling roof shingles. This unique structure plays a crucial role in protecting the inner layers of the hair, namely the cortex and medulla, from environmental damage, such as UV radiation and chemical exposure. The cuticle also contributes to the overall appearance of the hair by influencing its shine and smoothness.

By understanding the role of the cuticle, you can appreciate its importance in hair health and cosmetic treatments. For instance, maintaining the integrity of the cuticle is paramount in waxing practices and other hair removal techniques, as a damaged cuticle can lead to issues such as split ends and brittleness. Knowing this can help practitioners provide better hair care advice to clients.