What is the primary mechanism by which viruses replicate?

Viruses replicate primarily by hijacking host cells to reproduce. Unlike bacteria, which can divide independently through binary fission, viruses lack the necessary cellular machinery to replicate on their own. When a virus infects a host cell, it injects its genetic material into the host. This genetic material then takes over the host's cellular machinery, redirecting it to produce viral components such as proteins and nucleic acids.

Once sufficient viral components are synthesized, new viruses are assembled using these parts. Eventually, the host cell may burst, releasing the new viral particles to infect more cells. This exploitation of the host's biological processes illustrates the parasitic nature of viruses, which can only replicate by utilizing the host's resources, making them fundamentally different from self-replicating organisms like bacteria.

The other options describe mechanisms that do not apply to viruses. For instance, while some organisms can remain dormant until conditions are favorable, viruses do not have the capacity to exist in a dormant state in the same sense as more complex life forms like plants or fungi. They also do not perform photosynthesis, which is exclusive to autotrophic organisms. Therefore, the necessity for a host cell for replication is a defining characteristic of viral life cycles.