Protozoans belong to the protist kingdom. All protists are eukaryotes. Protozoans are a category of protists that are described as “animal-like” because they possess some characteristics resembling animals rather than plants. Protozoans are unicellular (made of one cell) heterotrophs. This means that they cannot make their own energy by photosynthesis. Instead they must ingest food to make energy. Protozoans are mobile and are able to move around to find food for themselves. Different protozoans move in different ways whether it is by pseudopods, cilia or flagella. Some protozoans play a beneficial role in an ecosystem and have symbiotic relationships with other organisms. Some protozoans, on the other hand, can have mutualistic or parasitic relationships with other organisms.