The proteins in the body are made of combinations of individual amino acids, known as the building blocks of protein. Amino acids are composed of a central carbon connected to a hydrogen atom, an acid group, an amine group, and a side chain. The is the group that varies for each amino acid.

The side chain  is the group that varies for each amino acid.

Proteins are very important molecules in the body. Proteins perform different important functions in the body and are part of several biochemical processes.

Proteins are composed of amino acids. The general formula of an amino acid is shown where R is commonly called the side chain.

The side chain R varies for each amino acid.

Learn more: link

side chain

Explanation:

Each amino acid is bound to a unique chemical group called its side chain. It is this side chain that makes each amino acid different, giving each amino acid a unique set of chemical properties. The side chain is often abbreviated as an R group and denoted with the letter R for short.

chemical digestion occurs in the stomach were hcl and pepsin forms chyme, the mouth in which salivary amylase breaks down starch to form bolus, and the small intestine specifically the duodenum.