Keratin and Hemoglobin Are Both Proteins with Important Functions in the Human

Keratin and hemoglobin are both proteins with important functions in the human body.Keratin has a long, thin, rope-like structure with a structural role in hair, fingernails, and skin.Hemoglobin has a compact, round, globular structure with a transport role in carrying oxygen to body cells from the lungs.Which statement best explains how both keratin and hemoglobin can be classified as proteins yet have such different structures and functions?

A) Human DNA contains a specific gene for each protein.
B) The types of amino acids and their sequence in a protein determine that protein's structure and function.
C) A protein can undergo chemical modification in a cell, which can change both its structure and function.
D) The structure of a protein is very sensitive to its environment and can change when environmental conditions change.
E) Different cells express different genes, which can account for differences in proteins produced by cells of different parts of the body.