Multiple choice

Silk contains a protein known as

  1. fibrin

  2. casein

  3. fibroin

  4. None of the above

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

Silk fibers are primarily composed of fibroin, a fibrous protein produced by silkworms. Fibrin is involved in blood clotting, casein is milk protein, making fibroin the correct silk protein.