Breathing, eating, walking, etc, are very natural human functions. But most people do not think about how these basic actions take place. For example, when you eat a fruit, you do not contemplate on how it will be made useful to your body. The only thing on your mind is eating a satisfying meal; at the same time, your body is involved in extremely detailed processes unimaginable to you in order to make this meal a health-giving thing. The digestive system where these detailed processes take place starts to function as soon as a piece of food is taken into the mouth. Being involved in the system right at the outset, the saliva wets the food and helps it to be ground by the teeth and to slide down the esophagus. The esophagus transports the food to the stomach where a perfect balance is at work.