Most likely due to the fact protists or protozoas causes diseases such as malaria and some are parasitic. And the major problem is they're microscopic making them a misfit for us and other organisms.
Answer:
Aerobic respiration produces much more ATP than anaerobic respiration. Anaerobic respiration occurs more quickly than aerobic respiration. hope this helps out a little
The evolution of the two species are very closely related but not identical
