Question

why are viruses considered to be nonliving?
a. they cannot use energy.
b. they have no genetic material.
c. they do not respond to their environment.
d. they cannot reproduce without a host cell.

Explanation:

Living organisms can reproduce independently. Viruses lack the cellular machinery to reproduce on their own and rely on a host cell for replication. They do have genetic material (either DNA or RNA), can respond to their environment in a limited way related to host - cell binding, and can use the host - cell's energy for replication processes. But the key factor that classifies them as non - living in many contexts is their inability to reproduce without a host cell.

Answer:

D. They cannot reproduce without a host cell.