A)is a covalent bond between the carboxyl carbon of one amino acid and the amino nitrogen of a second amino acid. B)is a covalent bond between the functional R groups of adjacent amino acids. C)is a covalent bond between the NH group of one polypeptide and the CO group of an adjacent polypeptide that holds together multimeric proteins. D)is a noncovalent bond that dictates the tertiary structure of a protein. E)is a covalent bond between adjacent glucose molecules in a peptide.