Which of the following best describes "Spirillum"?

Spirillum is a term used to describe a specific shape of bacteria that are characterized by their spiral or corkscrew-like structure. This morphology allows them to move in a distinctive manner compared to other bacterial shapes. Their spiral form facilitates motility, enabling these bacteria to navigate through their environments more effectively, which can be particularly advantageous in aquatic habitats where they are often found. The other shapes—round/spherical, rod-shaped, and curved rod—describe different bacterial forms that exhibit distinct characteristics and shapes unrelated to the corkscrew morphology of spirilla. Thus, the description that identifies spirillum as being spiral or corkscrew is the most accurate representation of this group of bacteria.