Plant-like protists include different groups of organisms, such as different types of algae, diatoms, dinoflagellates and euglenoids. Protists can be either uni-cellular or multicellular. For example, in the algae group, red algae are multicellular, but certain types of green algae can be either uni-cellular or multicellular.
Seaweed and kelp are types of multicellular algae, while phytoplankton are unicellular. Diatoms, dinoflagellates and euglenoids are typically uni-cellular organisms. Dinoflagellates have flagella for movement in water. If red dinoflagellates reproduce quickly, red tides, which can be toxic if eaten, may appear in bodies of water.
Protists are eukaryotic organisms that live in water or moist regions. Some, such as green algae, can make their own food through photosynthesis, while others are heterotrophs that eat other protists. For example, some types of euglenoids do not contain chloroplast, so they eat other protists.