Questions: Technically speaking, viruses are not microorganisms because they are not composed of cells, big enough for life, visible without a microscope, carbon-based.

The answer is the first one: composed of cells.

Explanation for each option:

• Composed of cells: Viruses are not considered microorganisms because they are not composed of cells. They lack the cellular structure that is a fundamental characteristic of living organisms. Instead, viruses consist of genetic material (DNA or RNA) enclosed in a protein coat and sometimes a lipid envelope.
• Big enough for life: This option is incorrect because the size of an organism does not determine whether it is considered a microorganism. Many microorganisms, such as bacteria and some fungi, are very small but still considered living organisms.
• Visible without a microscope: This option is incorrect because many microorganisms, including bacteria and protozoa, are not visible without a microscope, yet they are still considered living organisms.
• Carbon-based: This option is incorrect because viruses, like all known life forms, are carbon-based. The fact that they are carbon-based does not exclude them from being considered microorganisms.

Summary: Viruses are not considered microorganisms because they are not composed of cells.