Classify polymers based on their source.

(N/A) Based on their source,polymers are classified into three categories:
$(a)$ Natural polymers: These polymers are found in plants and animals. Examples include proteins,cellulose,starch,some resins,and rubber.
$(b)$ Semi-synthetic polymers: These are derived from naturally occurring polymers by chemical modifications. Examples include cellulose derivatives such as cellulose acetate (rayon) and cellulose nitrate.
$(c)$ Synthetic polymers: These are man-made polymers. Examples include plastics (e.g.,polythene),synthetic fibres (e.g.,nylon-$6,6$),and synthetic rubbers (e.g.,Buna-$S$),which are extensively used in daily life and industry.