<unk> is a process of energy production in a cell under anaerobic conditions (with no oxygen required). In common usage<unk> is a type of anaerobic respiration, however a more strict definition exists which defines<unk> as respiration under anaerobic conditions with no external electron acceptor.<unk> does not necessarily have to be carried out in an anaerobic environment, however. For example, even in the presence of abundant oxygen, yeast cells greatly prefer<unk> to oxidative phosphorylation, as long as sugars are readily available for consumption .
Sugars are the common substrate of<unk>  and typical examples of<unk> products are ethanol, lactic acid, and hydrogen. However, more exotic compounds can be produced by<unk>  such as butyric acid and acetone. Yeast famously carries out<unk> in the production of ethanol in beers, wines and other alcoholic drinks, along with the production of large quantities of carbon dioxide. Anaerobic respiration in mammalian muscle under periods of intense exercise (which has no external electron acceptor) is, under the strict definition, a type of<unk>
Fermentation 
Fertilization
Inoculation
Sterilization 
Solution
Swelling 
Reproduction
Freeze drying