Answer: Fermentation must create a net gain of ATP.
Explanation: Fermentation is a process in which organisms such as yeast, bacteria convert sugar into an alcohol or an acid. It is an anaerobic process because it does not require oxygen. The fermentation process is completed in the cytoplasm with a net gain of 2ATP during the glycolysis. Although it is a common pathway it is not the only method used by organisms produce ATP anaerobically.