Protozoa are part of the food chain, so that's one benefit these single-celled micro-organisms deliver. Some protozoa also help us control bacteria. Interestingly, there are more protozoa in the world than any other sort of animal. They can be found in fresh water, the sea and in soil. Scientists class protozoa into four types:
Amoeba
Amoebas stretch out their pseudopods to reach into the immediate environment and eat it up. It's quite gross.
Ciliates
These ones eat the bacteria in raw sewage so that's a benefit for us humans. They have tiny hairs coming off them called cilia, which they use like legs to get from one place to the next.
Flagellates
Flagellates have one or more flagella on their bodies, which they use to move themselves about.
Sporozoans
Unlike the other protozoa, sporozoans are m=not mobile - they need something (or someone...) to live inside. If you ingest them they make you sick.
