Answer:
The R organic group.
Step-by-step explanation:
Amino acids are a complex of organic compounds that combine to build proteins. The general structure of an amino acid is set by a carboxyl group (―COOH), a basic amino group (―NH2), and an organic R group, unique in every amino acid.
The amino acids differ from each other in the particular chemical structure and organization of hydrogen, nitrogen, carbon and oxygen atoms present in the organic R group.