What statement about bacteria is true?

The statement that all bacteria are single-celled organisms is accurate because bacteria are classified as prokaryotes, which are characterized by their lack of a defined nucleus and organelles, distinguishing them from eukaryotic cells. This single-celled structure allows bacteria to perform all necessary life processes independently, including reproduction, metabolism, and responding to environmental stimuli.

In contrast to this statement, not all bacteria are harmful; in fact, many types of bacteria play vital roles in ecosystems, such as decomposing organic matter and contributing to nutrient cycles. Additionally, bacteria come in various shapes, including rods, spirals, and spheres, which debunks the claim that they are all round. Furthermore, bacteria reproduce asexually through a process called binary fission, which means they do not require other living cells for reproduction, further solidifying why the other statements do not hold true.