What term describes bacteria that form columns or bands in chains or pairs?

The term that describes bacteria that form columns or bands in chains or pairs is "streptococci," which are spherical (cocci) bacteria that occur in chains. The prefix "strepto-" refers specifically to this tendency to form linear arrangements. In contrast, "diplococci" describes pairs of cocci, indicating that these bacteria often appear as two connected cells.

Staphylococci, on the other hand, are arranged in clusters or grapelike formations, which differentiates them entirely from the chained formations seen in streptococci. Bacilli refer to rod-shaped bacteria and do not align with the description of spherical bacteria that form chains or pairs. Finally, while "cocci" refers to spherical bacteria, it does not specify the arrangement, which is crucial for distinguishing between different types of these bacteria. Therefore, the combined term "streptococci or diplococci" accurately encapsulates the bacteria that form these distinctive arrangements.