Answer:
stratum corneum
Explanation:
Keratin is a structural protein that builds up hair, skin and nails.
The stratum corneum is the outer most layer of the epidermis that contains Keratinized cells. It serves as the primary protective barrier. Its thickness varies throughout the body .
The hair shaft is the part of the hair seen above the skin. Just like the stratum corneum , it is also made up of the protein keratin compacted and fused together.
