I am not sure, but to me it sounds that this is important because human populations are sometimes concentrated in areas that are lacking resources. Although, all of the given options may be correct.
Answer:
All viruses contain nucleic acid, either DNA or RNA (but not both), and a protein coat, which encases the nucleic acid. Some viruses are also enclosed by an envelope of fat and protein molecules. In its infective form, outside the cell, a virus particle is called a virion.
Explanation:
D. Carbon moved in a cyclic fashion through the atmosphere and living organisms
