Cows, goats, and sheep require symbiotic microbes to help digest the plant biomass that they eat, and some of these microbes make methane.
How does your body know to stop digesting after all the food is gone?
How do vultures avoid getting sick since they are known as nature's "clean up crew?"
When our brain tells us its time to eat, a reflex kicks in that makes the stomach walls contract. The contractions cause the digested food in the intestine to move down towards the rectum.
For the most part fat is stored in the fat cells that compose fatty tissue. Think of a fat cell as a tiny plastic bag filled with a drop of fat. Interestingly, fat cells do not multiply.