Kingdom Protoctista is a classification for single-celled microorganisms with eukaryotic cells, typically unicellular aquatic microorganisms. It includes water molds, slime molds, algae, and protists. Protoctists live exclusively in aquatic conditions and many are parasites. The five-kingdom classification scheme excluded organisms that were not animal, fungus, plant, or prokaryote. The discovery of unicellular organisms with multicellular […]