Answer: a. to provide support and structure for cells in hair, skin, and nails
Explanation:
Keratin - Wikipediaen.wikipedia.org › wiki › Keratin
Keratin (/ˈkɛrətɪn/) is one of a family of fibrous structural proteins known as scleroproteins. α-Keratin is a type of keratin found in vertebrates. It is the key structural material making up scales, hair, nails, feathers, horns, claws, hooves, calluses, and the outer layer of skin among vertebrates.
