The answer is C, hope I helped (:
A) Taiga
This is shown by the cold winters and the animal life in the example.
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.