They mostly have one membrane-bound nucleus in the cell that has diffused appearance due to scattering of the chromatin material, the vesicular nucleus contains a central body said to be either endosome or nucleoli.
The central vacuole performs the function of osmoregulation.
Membrane-bound cell organelles such as mitochondria, Golgi bodies, lysosomes and other specialised structures are found.
Most of the protozoa species have cilia, flagella, or pseudopodia for locomotion.
They are heterotrophic and have holozoic nutrition.
They ingest food by phagocytosis for which they have a specialised structure known as cytostome for phagocytosis.