Which of the following is a feature of a viral infection?

A viral infection is characterized by its dependence on a host organism for replication. Viruses are obligate intracellular parasites, meaning they cannot replicate or reproduce without entering a host cell. Once inside the host, the virus hijacks the cellular machinery to produce new virus particles, which is intrinsic to its life cycle. This is a fundamental property of all viruses, distinguishing them from other pathogens like bacteria, which can often live and reproduce independently.

The other choices do not represent features of a viral infection. Antibiotics, for instance, target bacterial infections and are ineffective against viruses. Viral infections are not caused by bacteria but rather by viral agents. It is also important to note that while some viral infections can resolve without medical intervention, this is not a defining feature of all viral infections, as some may require specific antiviral treatments or may lead to complications. Thus, the necessity for a host for replication is the primary characteristic that accurately describes viral infections.