Which of the following are the three main layers of the hair shaft?

The three main layers of the hair shaft are indeed the cuticle, cortex, and medulla. The cuticle is the outermost layer, consisting of transparent, overlapping cells that protect the hair from environmental damage and help maintain moisture. The cortex lies beneath the cuticle and is the thickest layer, containing tightly packed cells that provide strength, color, and texture to the hair. Finally, the medulla is the innermost layer, which may not be present in all hair types, but in those that have it, it contributes to the overall structure of the hair shaft. Understanding these three layers is essential for various hair treatments and for recognizing how different factors affect hair health and appearance.