Respuesta :
Based on the data collected, an organic substrate (such as starch) must be added to the yeast in the test tube in order to facilitate fermentation.
Fermentation is an anaerobic chemical reaction in which an organism breaks down and converts an organic substrate (such as starch) into an alcohol or an acid with the release of carbon dioxide as a waste product. For example, the organism (yeast) undergoes fermentation to produce energy by converting sugars into alcohol or acetic acid.