Afalcultative anaerobic organism is able to perform aerobic respiration in the presence of oxygen and fermentation in the absence of oxygen. an example of a falcultative anaerobic organism is brewer's yeast, which is used in the production of alcoholic beverages. if sealed in a vessel containing oxygen gas, water, and sugar (glucose), the yeast will eventually deplete the oxygen gas. as long as glucose is available, however, the yeast can still survive. brewer's yeast use oxygen preferentially because

the potatoes have high sugar concentrations and although these potatoes were different we could seethe effects that their sugar concentrations had in different environments. for example, the potatoes in sample a, were placed in pure water. this created a hypertonic environment and caused the potatoes to draw in water from its surroundings. we saw the opposite happen with the potatoes in sample b when placed in the sodium chloride solution. the potatoes in this case were in a hypotonic solution and therefore lost water to their surroundings.