Question

bacteria, viruses, protozoa, and green algae are all microbes, but one group is much smaller in size than the rest. which microbe is the smallest?
a. a bacterium
b. a virus
c. a green algae cell
d. a protozoan

Explanation:

Viruses are acellular entities (not composed of cells) and are much smaller in size compared to bacteria (which are single - celled prokaryotes), protozoa (single - celled eukaryotes), and green algae cells (which can be single - celled or multicellular eukaryotes). Bacteria range from about 0.5 - 5 micrometers in length, protozoa can be from a few micrometers to several hundred micrometers, green algae cells can vary but are generally larger than bacteria, while viruses range from about 20 - 300 nanometers.

Answer:

B. a virus