Question

question 18
which part(s) of different amino acids is/are different?
the r group
the central carbon
the amino group
the carboxyl group
all of them

Explanation:

All amino acids have a central carbon bonded to an amino group, a carboxyl group, a hydrogen atom, and an R - group. The amino group, carboxyl group, and central carbon are common features. The R - group is what varies among different amino acids, giving them their unique chemical properties.

Answer:

the R group