What is the main characteristic of viral infections?

The main characteristic of viral infections is that they cannot reproduce on their own. Viruses are unique in that they lack the cellular machinery necessary for replication. Instead, they must invade a host cell and hijack the host's cellular processes to multiply and propagate. This dependency on host cells for reproduction is a defining feature that differentiates viruses from living organisms, which can reproduce independently.

While some other options may address aspects of infections, they do not accurately reflect the fundamental nature of viruses. For example, viral infections cannot be treated with antibiotics, which are specifically designed to combat bacteria, and not viable against viruses. Not all viral infections pose life-threatening risks; many are mild and self-limiting. Additionally, the duration of viral infections can vary widely, and they are not inherently shorter-lived than bacterial infections; both types can have chronic or acute presentations depending on the specific infection and individual circumstances.