cellulose
Intestinal flora
Broken down into starch and glycose
It is broken down by bacteria.
by enzymes
in the digestive process, complex foods are broken down into simpler substances like what?
corn....and sand
Sewage
food not plastics or metals
Bacteria. Yes, but much of it can't be broken down and it is passed in the feces.
If you mean flatus, it's produced by the action of intestinal bacteria. Beans are commonly known for producing flatulence. They contain complex polysaccharides that cannot be broken down by human digestive enzymes, but intestinal flora does have the necessary enzymes to break these down (with a resultant production of methane, the principal constituent by volume of "gas").
Cows, horses, sheep, goats, and termites have bacteria living inside their intestinal tract. These bacteria can break down cellulose that is in grass and other plants.
Tooth enamel is broken down when bacteria feed off the sugars on your teeth. Their waste is the acid that breaks down your enamel.