Facultative bacteria are able to work in the presence as well as in the absence of oxygen. They are able to switch between aerobic respiration and anaerobic respiration depending on the availability of oxygen. Aerobic respiration is a more efficient process that produces more ATP, but it requires oxygen. Anaerobic respiration is a less efficient process that produces less ATP, but it does not require oxygen. Facultative bacteria are able to survive in a wide range of environments, including those that are low in oxygen.
Option A is incorrect because facultative bacteria can also work in the absence of oxygen. Option B is incorrect because facultative bacteria can also work in the presence of oxygen. Option C is the correct answer because facultative bacteria can work in both the presence and absence of oxygen. Option D is incorrect because facultative bacteria do not require water to work.