Protozoan (noun)

A single-celled organism that is a type of animal, typically found in water or soil.

Origin:

From the greek words protos, meaning 'first', and zōon, meaning 'animal'.

Examples:

1. The protozoan species Paramecium is a common subject of study in biology classes.
2. The presence of the protozoan parasite Giardia in drinking water can cause illness.
3. The role of protozoa in the food chain is as primary consumers of organic matter.
4. The diversity of protozoan shapes and behaviors was remarkable to observe under the microscope.
5. The study of protozoa has provided important insights into the evolution of multicellular life.