Approximately, 50,000 types of Phylum Protozoa have been identified. Its four divisions are Amoeboid Protozoa or Sarcodines, Flagellated protozoans or Zooflagellates, Ciliated protozoa or Ciliates and the Sporozoans.
Hint: Euglena, Amoeba, Plasmodium, Paramecium, Podophyllum a few examples of Phylum Protozoa. Approximately, 50,000 types of Phylum Protozoa have been identified. Its four divisions are Amoeboid Protozoa or Sarcodines, Flagellated protozoans or Zooflagellates, Ciliated protozoa or Ciliates and the Sporozoans.
I will have to say D) they keep the prey population low so they will be less likely to deplete resources such as food, water, and shelter... hope i helped!!