Which statement is true about protozoa?

• A. They are not parasites
• B. They are viruses
• C. They can be parasitic or free living
• D. They are fungi

Answer: (C)

Protozoa are single-celled eukaryotes that show a wide range of lifestyles. Some live freely in water or soil, feeding on bacteria and other small organisms, while others are parasitic, living inside a host and deriving nutrients at the host’s expense. This diversity—being either free-living or parasitic—makes the statement true. Protozoa are not viruses; viruses are noncellular particles that require a host cell to reproduce. They are also not fungi, which are a different group of organisms with distinct cellular structures and modes of nutrition. Examples include free-living amoebae or paramecia, and parasitic ones like Plasmodium (malaria) and Giardia lamblia.