Spirilla, a type of bacteria, are best described as which of the following?

• A. Helically shaped bacteria with rigid bodies
• B. Spherical bacteria that form clusters
• C. Rod-shaped bacteria that form chains
• D. Comma-shaped bacteria with flexible bodies

Answer: (A)

Verified step by step guidance

1. Understand the question is asking for the description of Spirilla, a type of bacteria, based on their shape and physical characteristics.
2. Recall the common bacterial shapes: spherical (cocci), rod-shaped (bacilli), comma-shaped (vibrios), and spiral-shaped (spirilla or spirochetes).
3. Identify that Spirilla are known for their spiral or helical shape, which distinguishes them from other bacterial forms.
4. Note that Spirilla have rigid bodies, unlike spirochetes which are also spiral-shaped but have flexible bodies.
5. Match the description 'Helically shaped bacteria with rigid bodies' to Spirilla, differentiating them from spherical clusters, rod-shaped chains, and comma-shaped flexible bacteria.