Which term describes a single-celled organism that often lives in water and can move?

Which term describes a single-celled organism that often lives in water and can move?

• A. Bacteria
• B. Fungus
• C. Protozoa
• D. Virus

Answer: (C)

Protozoa are single-celled, eukaryotic organisms that often inhabit water and can move using structures like flagella, cilia, or pseudopods. This combination of being one cell in size and actively motile in aquatic environments best fits the description. While bacteria are also single-celled, they are prokaryotes with different cellular structure, and viruses are not cells and cannot move on their own. Fungi are usually multicellular and non-motile, with yeastsbeing single-celled but not typically motile in water the way protozoa are.

Protozoa are single-celled, eukaryotic organisms that often inhabit water and can move using structures like flagella, cilia, or pseudopods. This combination of being one cell in size and actively motile in aquatic environments best fits the description. While bacteria are also single-celled, they are prokaryotes with different cellular structure, and viruses are not cells and cannot move on their own. Fungi are usually multicellular and non-motile, with yeastsbeing single-celled but not typically motile in water the way protozoa are.