Proteins. <span>The amino acids in a polypeptide chain are linked by peptide bonds. Once linked in the </span>protein<span> chain, an individual amino acid is called a residue, and the linked series of carbon, nitrogen, and oxygen atoms are known as the main chain or </span>protein<span> backbone.</span>
The answer is D because bacteria is one or more cells.
Explanation:
adrenocorticotropic hormone= It stimulates the adrenal cortex.
