What term describes bacteria that can produce a protective coating against harsh environments?

The correct answer is bacterial spores. Bacterial spores are a resilient form of certain bacteria that allow them to survive extreme environmental conditions, such as high temperatures, dehydration, and exposure to chemicals. When conditions become unfavorable for bacterial growth, some bacteria can convert themselves into spores, which are encased in a tough outer coating. This coating provides protection against desiccation, heat, and radiation, enabling the bacteria to endure until conditions improve and they can reactivate and multiply again.

This is distinct from viral cells, which are not bacteria and do not form spores; they require a host to replicate. Plasmids are small, circular DNA molecules found inside bacteria; they are not a protective mechanism but can confer antibiotic resistance. Prokaryotes refer to a broad category of organisms that includes bacteria, but not all prokaryotes can form spores, making them too general for this specific question. Thus, bacterial spores specifically denote the ability to produce a protective coating against harsh environments.