Which term describes spiral-shaped bacteria?

• A. Capsule
• B. Spiral
• C. Diplo
• D. Staphylo

Answer: (B)

Understanding how bacteria are described involves two main ideas: shape and arrangement. The term that conveys the physical geometry of spiral-shaped bacteria is spiral, because it directly communicates that the cells have a curved, helical outline rather than being spherical or rod-like. Capsule describes an outer protective layer around the cell, not its shape. Diplo- indicates cells paired in twos, and staphylo- describes grape-like clusters, which are about arrangement, not shape. In this context, spiral is the best fit because it explicitly labels the geometry of the organisms in question. (In more precise microbiology, spirilla or spirochetes are used for spiral or corkscrew shapes, but for this question, spiral correctly signals the curved form.)