Indiana State Barber Practice Exam

As the cells of the hair shaft mature, they do not fill up with water (A) because water is not a major component of hair. Melanin (B) plays a role in hair color, but it is not the main substance that fills the hair shaft. Collagen (D) is a protein found in connective tissue and is not a major component of hair. Instead, it is keratin (C) that fills up the cells of the hair shaft, giving hair its strength and structure.