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.
"The Feynman Technique is a mental model that was coined by Nobel-prize winning physicist Richard Feynman. Known as the "Great Explainer," Feynman was revered for his ability to clearly illustrate dense topics like quantum physics for virtually anybody."
Answer:
I would if I knew what u needed help with. sorry:(
The answer is the third one