Answer:
The best answer is R group. An R - group is a chemical group or side chain that is found attached to the central carbon in amino acids
Explanation:
Carbonate groups contain a single carbon atom, and three oxygen atoms in a trigonal molecular geometry. The carbon atom has two single bonds to two oxygen atoms and a double bond to the third oxygen atom. Therefore, in addition to carbon, carbonate minerals contain oxygen. An example of a carbonate mineral is calcium carbonate, often found within rocks.
