Answer: Formed by intermediate filaments
Step-by-step explanation:
Keratin belongs to the family of fibrous structural proteins. It is found in abundant amount inside the human body.
Hair constitutes of about 90% of keratin protein. The epidermis is the outer layer of skin which is formed by scale like cells known as epithelial cells and specialized cells known as keratinocytes.
These cells protect the body from the outer damage and is formed by long strands of proteins(intermediate filament) inside the cell, hence called keratin.
This is how keratin is made inside the body.