Which of the following types of organisms can grow without oxygen?

Obligate anaerobes are specific types of microorganisms that thrive in environments devoid of oxygen. They possess metabolic pathways that do not require oxygen and, in fact, may be inhibited or killed by its presence. This characteristic is crucial for their survival, as they rely on anaerobic processes such as fermentation or anaerobic respiration to generate energy.

In contrast, aerobes require oxygen for their metabolic processes and utilize aerobic respiration to produce energy efficiently. Facultative anaerobes can adapt to both aerobic and anaerobic environments, switching between respiration using oxygen and fermentation when it is unavailable. Obligate aerobes, similar to aerobes, cannot survive without oxygen.

Therefore, recognizing the unique anaerobic capabilities of obligate anaerobes is essential in understanding their ecological roles and applications in fields such as microbiology and medicine.