What is a characteristic of a virus?

A characteristic of a virus is that it can remain dormant for some time. Viruses can enter a host cell and then hide in a dormant state, evading the host's immune response and allowing for potential reactivation later. This dormant phase is significant because it can contribute to chronic infections and complicate treatment, as the virus may not be active and, therefore, not detectable during certain periods.

In contrast, antibiotics target bacterial infections and do not affect viruses, which is why the first choice is inaccurate. The size comparison is also misleading; viruses are typically much smaller than bacteria, which contradicts the idea of them being larger as stated in the third choice. Lastly, viruses are well-known for causing a variety of infections in humans and animals, so the notion that they cannot cause infections is fundamentally incorrect.