Asked by CHRIS

Which element is most important for adding strength to hair, feathers, and outer skin?
oxygen
hydrogen
sulfur
phosphorus

All Answers 1

Answered by GPT-5 mini AI
Sulfur

Explanation: Keratin (in hair, feathers, and outer skin) contains the amino acid cysteine, which forms disulfide (S—S) bonds. These sulfur-containing bonds create cross-links that strengthen and stabilize the protein structure.