Flexi Says: Our own enzymes cannot digest many of the foods we eat. To break down these foods we have a gut full of trillions of bacteria. In the lower intestine, these bacteria derive their energy by finishing off digestion through fermentation or anaerobic respiration. By-products of fermentation and anaerobic respiration include gasses like carbon dioxide, methane, and hydrogen. The methane and hydrogen make farts flammable!
