Viruses that infect bacterial cells do not infect human cells and viruses that infect human cells do not infect bacterial cells. explain why this should be the case

This is because viruses bind to specific receptors on the host cell. For example, bacteriophages-viruses that infect bacterial cells, attach to receptors on the surface of bacteria, such as lipopolysaccharides or teichoic acids. Receptors determine the viruses host.

Viruses infect all types of cellular life, but often are specific for the species, so we differ human, animal, plant and bacterial viruses. Viruses that infect plants are harmless to animals and vice versa.

i think the answer is b.

this age may represent the age of the earth's accretion, of core formation, or of the material from which the earth formed. this dating is based on evidence from radiometric age-dating of meteorite material and is consistent with the radiometric ages of the oldest-known terrestrial and lunar samples.