Answer: 2. Each subunit represents a separate polypeptide chain, while one polypeptide chain may contain several domains.
Explanation: Each subunit constitutes of one polypeptide chain. A polypeptide chain has one particular gene coding for it. thus it simply implies that a protein must have one gene for each subunit.
Many proteins is made up of different protein domains. A particular domain may appear in a variety of different proteins.
domains are stable on there own, they can be exchanged via genetic engineering between one protein and another.
Organisms who happen to be best suited to an environment and reproduce most successfully will be consider successful in terms of natural selection.
