Protozoans consist of two parts: i.e., eukaryotic and single-celled organisms.
The four major groups of Protozoa are:
Amoeboid protozoans:
Amoeboid protozoans- It lives in fresh or sea water or in moist soil.
Amoeboid Protozoans develop pseudopodia which are temporary protoplasmic outÂgrowths.
Examples: Amoeba, Entamoeba
Flagellated protozoans:
Flagellated protozoans- It can be either free-living or parasitic.
Parasitic forms can cause diseases like sleeping sickness.
Flagellates are protozoans with one or a small number of long whip-like hairs called flagella that are used for locomotion.
Ciliated Protozoans:
These protozoans have numerous cilia on their body as cilia are actively moving organisms.
These organisms are aquatic.
Examples: Paramecium
Sporozoans:
These protozoans have an infectious spore stage in their life cycle.
They are parasites
Example: Plasmodium (which causes malaria)
Final Answer:
The four major groups of Protozoa are Amoeboid protozoans, Flagellated protozoans, Ciliated Protozoans and Sporozoans.