Parasites vary in size from which range?

• A. Microscopic viruses
• B. Large bacteria
• C. Tiny cells to visible worms
• D. Spores and cysts only

Answer: (C)

Parasites span a wide size range, from tiny single-celled organisms to larger, visible animals. That broad spectrum is captured by describing them as ranging from tiny cells to visible worms, which includes small protozoa as well as larger helminths. For example, protozoa like Giardia are only a few tens of micrometers, while many worms can be centimeters to meters long. The other options don’t fit because they either limit parasites to a much smaller group (viruses) or to specific forms (spores and cysts) or to a narrow size (large bacteria) without acknowledging the full spectrum.