Answer: D) lack the ability to reproduce without a host.
Step-by-step explanation:
Those who argue that the virus is not a living thing assume that he has no free life, for its replication is possible only within a living cell. Also, some of these agents can crystallize when subjected to adverse situations. Although they can replicate, viruses do not have the enzymatic apparatus sufficient for replication, thus requiring the cellular machinery to complete its replicative cycle, which makes it a mandatory intracellular parasite.
Its apparent fragility, being strictly cell-dependent, is dismissed by its ability to control and redirect cellular metabolism to its benefit. Despite the low structural complexity, it can cause major damage to the host cell, even though morphologically presenting only genetic material, a capsid and, in some viruses, an envelope.