Which among the following is a constituent of natural silk?

Correct answer: (c) Nitrogen

Explanation

Natural silk is made of the proteins fibroin and sericin, which are chains of amino acids.

Amino acids like glycine, serine and alanine all contain the amine (-NH₂) group, so silk is rich in nitrogen.

Potassium, magnesium and phosphorus are absent from silk's amino-acid structure.