Which term best describes the spiral-shaped bacteria?

The term that best describes spiral-shaped bacteria is "Spirilla." Spirilla are characterized by their corkscrew or spiral shape, which distinguishes them from other bacterial forms. This morphology allows them to move in a unique manner, often using flagella that enable them to navigate through different environments, including viscous environments such as mucous.

In contrast, cocci refer to spherical-shaped bacteria, while bacilli are rod-shaped. Vibrios are a specific type of bacilli that are comma-shaped, so they also do not represent the general classification of spiral-shaped bacteria as well as spirilla do. The precise classification of bacteria is critical in microbiology for identification, treatment, and understanding their roles in various environments or diseases.