Question

multiple-choice question
what is keratin?
a hair cell
a protein
a fat

Explanation:

Keratin is a type of protein that makes up structures like hair, nails, and the outer layer of skin. A hair cell is a different type of cell (e.g., in the ear for hearing), and keratin is not a fat. So the correct option is "a protein".

Answer:

B. a protein (assuming the options are labeled as A: a hair cell, B: a protein, C: a fat)