Answer:
What causes fermentation is the absence of oxygen.
Explanation:
Fermentation is the biochemical process carried out by some fungi and anaerobic bacteria to obtain energy. Fermentation is caused by the absence of oxygen. As already mentioned, the organisms that carry out the fermentation are anaerobic beings, for that reason, they are unable to perform cellular respiration to obtain energy, allowing the fermentation to bind the energy necessary to their organisms.
Fermentation takes place in the cytoplasm of cells and uses glucose (or other organic matter) to produce ATP.
