Protozoans are heterotrophs act either as predators or parasites.
They are of four groups
1. Amoeboid protozoans: They capture their prey by using pseudopodia. They live in freshwater. Some are parasites
Eg: entamoeba.
2. Flagellated protozoans: They are free-living or parasites. They cause diseases,
Eg: Trypanosoma-sleeping sickness.
3. ciliated protozoans: They possess cilia in their body surface for locomotion. They have gullet for food intake.
Eg: Paramecium
4. Sporozoans: They are sporeproducing organism that causes diseases
Eg: plasmodium causing malaria.
