Among the microbes responsible for producing fermented foods, the two most prominent groups are the lactic acid-producing bacteria and yeasts that produce .

Alcohol

Explanation:

Fermentation is a type of anaerobic respiration employed by organisms like yeast and certain species of bacteria. As stated in this question, YEAST and the BACTERIA that produces lactic acid as a product are the two major microbes that undergoes this fermentation process.

However, YEAST (a unicellular fungus) undergoes fermentation to yield alcohol and CO2 as its product. Yeast breaks down sugar molecules into ethanol (C2H5OH) and carbon dioxide (CO2) in its cells enabling it to be used in the production of fermented foods like cheese, beer etc.

the answer is:

carbon dioxide

digestion

it excretes wastes