Which of the following is TRUE of most bacteria?

• A. They are nonpathogenic
• B. They are always harmful
• C. They exist only in plant form
• D. They cannot live outside a host

Answer: (A)

Most bacteria are nonpathogenic, meaning the majority do not cause disease. They play essential roles in environments and in our bodies—helping with digestion, breaking down nutrients, and protecting against harmful microbes. Only a small subset are pathogenic. Bacteria are not plants and they can live in many places outside a host, including soil, water, and surfaces. They don’t exist only in plant form, and they aren’t inherently or always harmful, so the statement about them being nonpathogenic best reflects what’s true for most bacteria.