Texas Cosmetology License Practice Exam

The medulla is the innermost layer of hair and its primary function is to provide structural support. This means that options A, B, and D are incorrect because the medulla does not contribute to the strength or color of hair, nor does it have any role in moisture absorption. While some sources suggest that the medulla may have a small role in protecting hair from environmental stressors, its main function is still to provide structural support and protection for the hair shaft. Therefore, the correct answer is C, as the medulla does not have any substantive or significant function in hair.