Idaho Cosmetology Licensure Practice Exam

The outermost layer of hair is called the cuticle. The other options, cortex, epidermis, and dermis, represent layers of skin, not hair. The cortex refers to the innermost layer of hair, while the epidermis and dermis refer to layers of skin. The cuticle contains overlapping scales that help protect the hair and give it its shine. Therefore, cuticle is the most appropriate answer as it accurately describes the outermost layer of hair.