Which shape does the term 'cocci' refer to?

The term 'cocci' refers specifically to spherical-shaped bacteria. This shape is one of the fundamental classifications used in microbiology to categorize bacteria based on their morphology. Cocci can exist as single cells, in pairs (diplococci), in clusters (staphylococci), or in chains (streptococci), but they all share the common characteristic of being round.

Understanding bacterial morphology is crucial in microbiology because it can influence the identification, classification, and treatment of bacterial infections. The other options represent different bacterial shapes: 'rod' corresponds to bacilli, which are elongated and cylindrical; 'spiral' indicates shapes that are twisted or corkscrew-like, known as spirilla or spirochetes; and 'comma' refers to vibrio, which are curved rod-shaped bacteria. Each of these shapes presents different characteristics and behaviors in a clinical setting, making the accurate identification of cocci essential for microbial diagnosis and treatment strategies.