A lab technician observes a unicellular organism with two long flagella and two nuclei in the blood smear of a person. To which phylum does this protozoan belong?

A. Zooflagellata

B. Ciliata

C. Sarcodina

The answer is letter A. Zooflagellata is a phylum within the kindom Protista. They are a unicellular organism with two long flagella that may form symbiotic, commensal, or parasitic relationships with humans, animals, and certain types of plants. They can also be found free-living and they have the capacity to assimilate organic material through the process of osmotrophy (absorption through the plasma membrane) or phagotrophy (engulfing prey in food vacuoles). This explains why it is found in the blood smear of the person being observed by the technician.