Q. Which of the following is the major ingredient of leather? (UPSC Prelims 1988)
Answer: Collagen
Notes: The major ingredient of leather is Collagen. Collagen is one of the most plentiful proteins in mammals. It is responsible for several biological functions, one of which is to provide structural support in connective tissue, muscle, and skin. Collagen is the protein responsible for skin elasticity. It also plays a role in joint and bone health.