whare did protozoa apper first
Answers
Answer:
Protozoa (also protozoan, plural protozoans) is an informal term for single-celled eukaryotes, either free-living or parasitic, which feed on organic matter such as other microorganisms or organic tissues and debris.[1][2] Historically, protozoans were regarded as "one-celled animals", because they often possess animal-like behaviours, such as motility and predation, and lack a cell wall, as found in plants and many algae.[3][4] Although the traditional practice of grouping protozoa with animals is no longer considered valid, the term continues to be used in a loose way to describe single-celled protists (that is, eukaryotes that aren't animals, plants, or fungi) that feed by heterotrophy.[5]
Answer:
at first these protozoans lived in the gut of the vertebrate host, but they gradually begin invading host tissues and eventually became adapted to spending their lifecycle in the bloodstream