This page discusses ciliates, complex single-celled protists visible to the naked eye and resembling multicellular organisms. Some biologists propose classifying them as acellular due to their intrica...This page discusses ciliates, complex single-celled protists visible to the naked eye and resembling multicellular organisms. Some biologists propose classifying them as acellular due to their intricate organization. Ciliates have a small diploid micronucleus that contains their genome and a large polyploid macronucleus for gene functions. They reproduce sexually, promoting genetic diversity.