Multiple choice

The skin is the largest organ in the body. Its outer layer is made up of ___________ protein.

  1. endostatin

  2. angiostatin

  3. keratin

  4. gelatin

Reveal answer Fill a bubble to check yourself
C Correct answer
Explanation

Keratin refers to a family of fibrous structural proteins. Keratin is the key structural material making up the outer layer of human skin. It is also the key structural component of hair and nails.