What is hair made of and how does it contribute to its overall structure and function?

Hair is made of a protein called keratin, which is also found in nails and skin. The structure of hair is determined by the arrangement of keratin molecules, which form a tough and flexible strand. The outer layer of the hair, called the cuticle, protects the inner layers and gives hair its shine. The inner layers, called the cortex and medulla, provide strength and elasticity. Overall, the composition of keratin and the arrangement of its molecules contribute to the strength, flexibility, and texture of hair.