What is common about Trypanosoma, Noctiluca, Monocystis and Giardia?

Trypanosoma, Noctiluca, Monocystis and Giardia are all unicellular protists. Trypanosoma gambiense is the single celled, parasitic zooflagellate causing trypanosomiasis or sleeping sickness. Giardia or the 'Grand old man of the intestine' is a parasitic flagellatte occurring in tthe intestine of man and other animals and causes giardiasis or diarrhoea (i.e. very loose and frequent stool containing large quantity of fat. Noctiluca is a marine, colourless dinoflagellatte. It is a voracious predator and has a long, motile tentacle, near the base of which, its single short flagellum emerges. Monocystis is a microscopic, unicellular endoparasitic protozoan found in the coelom and seminal vesicles of earthworm. As it is and endoparasite, it does not possess any special structure for locomotion.