Convergent evolution would be the best way to explain why two species that look similar are not necessarily that closely related. In convergent evolution, distinct species develop similar anatomical characteristics after its divergence from one common ancestor that does not possess the initial characteristic.
Answer:
Protozoa are single-celled eukaryotes
Explanation:
Eukaroytes are organisms whose cells have nuclei
The digestive system enlists the aid of the cardiovascular system and the nervous system. Blood vessels of the digestive system widen to transport more blood.