R H Whittakerdivided living organisms into five kingdoms$\ viz$, monera, Protista, Fungi, Plantae and Animalia. Kingdom-Protista includes eukaryotic, unicellular, autotrophic or heterotrophic organisms (both plants and animals) like flagellates, diatoms, dinoflagellates, slime moulds, sarcodina, etc. Themajor groups of Protista are photosynthetic protists (algae), consumer-decomposer protists (slime moulds) and protozoan protists.