How would you distinguish protists and members of their kingdoms?

Any eukaryotic species that isn't an animal, plant, or fungus is referred to as a protist. While protists are believed to have shared an ancestor, the absence of other eukaryotes implies that protists do not constitute a natural clade. Protists are unicellular, colonial, or less commonly multicellular organisms that include protozoans, most algae, and even fungus (such as slime molds).