Which of the following is not an example of a polymer 1. plastic

2. nylon

3. amino acid

4. polystyrene

The correct answer option is 3. amino acid.

Explanation:

Amino acids are the organic compounds that contain amine (-NH2) and carboxyl (-COOH) functional groups.

While a polymer is made up of a chain of monomers where the monomer is an amino acid. So when you have more number of amino acids, a polymer is formed.

It means that amino acid alone on its own is not a polymer.

Therefore, the correct answer option is 3. amino acid, rest all options are polymers.