Kingdom Protista: Protista includes all unicellular eukaryotic organisms, mainly aquatic and it is considered as a natural kingdom because it includes organisms of diverse lifestyles. They are mainly autotrophic producers (phytoplankton) in the oceans and others are predators and decomposers. They prepare their food in a natural way and feed the other organisms in the oceans. Protista is divided into three major groups: Photosynthetic Protists. Slime Moulds. Protozoan Protists. Photosynthetic Protists: Photosynthetic protists are the unicellular algae which constitute the major portion of the phytoplankton. They perform the process of photosynthesis and are passively drifted by the water current. They … Continue reading What kinds of organisms are grouped under Kingdom Protista? Would you consider this kingdom a natural one?