Nebraska Cosmetology State Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

Keratin is a crucial protein found in the hair structure, specifically making up the majority of the hair shaft. It provides strength, durability, and resilience, enabling hair to withstand mechanical stress and environmental factors. Being a fibrous structural protein, keratin contributes to the overall integrity and health of the hair. Strong and resilient hair strands are largely the result of the presence of keratin, which is essential for maintaining hair's natural shape and resilience.

The other options describe components or substances that are not accurate representations of keratin's role in hair. For example, while oils do contribute to moisture and shine in the hair, they are not related to the structural properties offered by keratin. Minerals may play a role in hair color, but keratin itself does not add any coloring properties to hair. Additionally, carbohydrates are not involved in the formation of hair structure, further distinguishing the role of keratin as a protein specifically responsible for strength in hair.