Question

Euglena are not the only organisms that have flagellum. Zooflagellates are protozoan that also have flagella. Although euglena and zooflagellates move by flagella, why are these organisms classified differently?

Answer 1

possession of flagellum is not a taxonomic feature. many different unrelated organisms have flagellum. euglena, zooflagellates but also some fungi or even human sperm cells.