Colorado Cosmetology Written Practice Exam 2026 - Free Cosmetology Practice Questions and Study Guide

Sebum is secreted by the sebaceous glands and is an oily substance that helps to lubricate the skin and preserve the softness of the hair. It also helps to protect the skin from dehydration and external elements.

Other options such as Keratin, Collagen, and Elastin play important roles in the structure and strength of the skin and hair, but they do not function as a lubricant. Keratin is a protein that makes up the hair and nails, Collagen is a protein that provides structure and elasticity to the skin, and Elastin is a protein that gives the skin and other tissues the ability to stretch and recoil. None of these substances are responsible for lubricating the skin or preserving the softness of hair. Therefore, they are not the correct answers to the question.