What is the correct definition of a virus?

A virus is correctly defined as a submicroscopic particle that requires a host to replicate. This is essential to understanding how viruses function and their impact on living organisms. Unlike other microorganisms, such as bacteria, viruses lack the cellular structure necessary for independent reproduction and metabolism. They are composed of genetic material (either DNA or RNA) encased in a protein coat, and they cannot replicate on their own. Instead, they invade host cells and hijack the cellular machinery to reproduce, leading to infection and various diseases.

This definition highlights the unique and parasitic nature of viruses, distinguishing them from other life forms that can survive and reproduce independently. Understanding this is crucial in the context of infection control in barbering and other fields, as appropriate sanitation and hygiene practices can help prevent the spread of viral infections.