Final answer:
Keratin is often a component of intermediate filaments, which are a diverse group of cytoskeletal elements. Keratin strengthens hair, nails, and the skin's epidermis.
Step-by-step explanation:
Intermediate filaments are a diverse group of cytoskeletal elements made up of several types of fibrous proteins. One of these proteins is keratin, which is often a component of intermediate filaments. Keratin is a fibrous protein that strengthens hair, nails, and the skin's epidermis.