I read that protozoa are unicellular and acellular. But unicellular mean they've one cell to perform all the life activities and then acellular mean without cell. so I'm confused what does that mean?and about reproduction in protozoa, it is said that though they prefer asexual reproduction but if sexual reproduction don't occur for a long time, the specie weakens. so my question is, say the specie has already strong genes important for the survival and it is transferred from generation to generation without variation, then why sexual reproduction is required?and please let's discuss protozoans characteristics. mostly a thread just get one reply but I want a little discussion for the sake of learning and revision.thanks.