Anatomical terminology. Digestion is the breakdown of large insoluble food molecules into small water-soluble food molecules so that they can be absorbed into the watery blood plasma. In certain organisms, these smaller substances are absorbed through the small intestine into the blood stream.
        
             
        
        
        
The process that occurs in a cell when there is not enough oxygen
is called fermentation. Fermentation occurs through the process of Anaerobic Respiration,
where instead of using oxygen, organic and inorganic molecules are used as
final electron acceptors. The by-product of this process is usually alcohol,
ethanol, or acetic acids.
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Fermentation is commonly used in lactic acid (in muscles) and alcohol (beers,
whiskey) fermentation where the by-product is ethanol. Yeasts are a common
organism that uses this process, where it convert sugars into alcohols or
acetic acids.</span>
        
             
        
        
        
It shows that a scientist can be creative because they used the fish's coughing technique to search for contaminated water.