Which of the following statements is true about viruses?

Viruses are classified as microbes but are fundamentally different from living organisms, which is why the statement that they are considered microbes but not living is accurate. Unlike living microorganisms, viruses lack the cellular structure and metabolic machinery necessary for independent life. They cannot reproduce on their own and require a host cell to replicate, which is a significant characteristic that differentiates them from living cells.

Moreover, viruses are composed of genetic material—either DNA or RNA—encased in a protein coat, and sometimes an additional lipid envelope, but they do not possess the typical organelles found in living cells. Thus, the assertion that they are not living aligns with the understanding in microbiology that defines life based on certain criteria that viruses do not meet.

The other choices imply characteristics not applicable to viruses: they do not exhibit the traits of living organisms such as metabolism or cellular structure, and while some viruses can have beneficial effects on hosts in specific contexts, this is not a universally applicable characteristic and does not define viruses overall.