What type of bacteria can survive in environments lacking oxygen?

The correct answer highlights that anaerobic bacteria are those specifically adapted to thrive in environments devoid of oxygen. These microorganisms have metabolic pathways that allow them to generate energy without the use of oxygen. This can include processes such as fermentation or anaerobic respiration, enabling these bacteria to survive and proliferate in various environments like deep soil, human intestinal tracts, and stagnant water.

While some other bacteria, such as facultative anaerobes, can tolerate or even utilize oxygen when present, they do not exclusively depend on anaerobic conditions for survival. In contrast, facultative anaerobes can switch between aerobic and anaerobic processes, demonstrating adaptability rather than a strict dependence on an oxygen-free environment. Consequently, anaerobic bacteria specifically denotes those organisms that thrive solely in the absence of oxygen, marking them as distinct within the broader bacterial classification.