The term "protozoa" is somewhat vague and may refer to the following two situations:
Single-celled organisms: refers to microorganisms in the kingdom of prokaryotes (also known as the kingdom of protists), including protozoa, flagellates, trichomonas and very simple multicellular organisms. They are usually single-celled organisms that do not possess the organs and tissue structure of eukaryotic cells.
Endemic: An animal that is unique to a particular area. For example, if you talk about "native animals" in a certain area, you may be referring to species of animals that are unique to that area, rather than to other areas.
Depending on the context, "protozoa" may include a variety of different organisms. If you are referring to microorganisms in the kingdom Prokaryotes, they include protozoa, flagellates, trichomonas, etc.; if you are referring to animals unique to a specific region, then "protozoa" will vary depending on the region.
