Natural silk is a
(A) Polyester
(B) Polyamide
(C) Polyacid
(D) Polysaccharide

Hint: An attempt to this question can be made by understanding the structure of natural silk. Now determine the repeating unit of this polymer. Identify the type of monomer it is. Based on this you can determine the type of polymer, natural silk is.

Complete step by step answer:
We will try to understand the process of polymerisation and then determine the type of polymer natural silk is.
Polymerization is a process of reacting monomer molecules together in a chemical reaction to form long polymer chains .
In chemical compounds, polymerization can occur by various types of reaction mechanisms that vary in complexity due to the functional groups present in the reactants and the steric effects that are present.
Natural is a protein fiber present obtained from nature. Some forms of silk can be woven into textiles. The cultivation of silkworms to obtain silk is called sericulture.
Natural silk is composed of mainly fibroin. It is a type of insoluble protein. It has a sequence of amino acids. The linkage of amino acids is by the formation of amide bonds. Thus, silk is a type of polyamide.

Therefore, the correct answer is option (B).

Note: Along with natural silk, exists another polymer called rayon. Rayon is often considered to be artificial. This is because the texture of rayon fabric is similar to natural silk. However, rayon is relatively cheaper to produce. When made out of bamboo viscose, the silk is commonly called bamboo silk.