A ruminant's stomach is composed of four chambers, the largest of which is the RUMEN. The RUMEN is a fermentation vat that contains bacteria and protozoa which break down the food that the animal has eaten. The other three chambers are the reticulum, omasum, and abomasum. The reticulum is where the food is stored and mixed with saliva, the omasum is where water and minerals are absorbed, and the abomasum is the true stomach where digestion takes place.