Iowa Cosmetology Practice Exam 2025 - Free Cosmetology Practice Questions and Study Guide

The cuticle layer of the hair plays a crucial role in protecting the inner layers, specifically the cortex and medulla, which are vital for the hair's strength and structural integrity. It is made up of overlapping flat cells that are relatively transparent, which helps reflect light and provide a natural shine to the hair. This protective barrier also minimizes damage from environmental factors, such as UV rays and pollutants, as well as mechanical stress from styling.

While the cuticle does contribute indirectly to the moisture balance of the hair by preventing excessive moisture loss, its primary function is not moisture provision. The cuticle does not contain melanin, and therefore it does not play a role in determining the hair's color; that function resides largely in the cortex. Additionally, while the health of the cuticle can influence the overall appearance of hair, it does not support hair growth directly. Hair growth is a process that takes place in the hair follicle and involves other structures and nutritional factors. Thus, the statement regarding the cuticle's protective capability and its role in providing shine is why this answer is correct.