Question

in this amino acid, which circle represents the r group? a h3c b o oh c nh2 b c a

Explanation:

An amino - acid has a general structure with an amino group ($-NH_2$), a carboxyl group ($-COOH$), a hydrogen atom, and an R - group attached to the central carbon. In the given structure, circle A represents the R - group as it is the variable part of the amino - acid structure. Circle B is the carboxyl group and circle C is the amino group.

Answer:

A. $H_3C$ (circle A)