Simply eating food is not enough to keep us alive and growing. Our bodies must change food into usable nutrients, and this process is called digestion. Digestion is both a mechanical and chemical process that breaks food down into molecules the body can absorb and use for energy, growth, and repair. Digestion begins the moment food enters the mouth and continues until waste leaves the body. Along the way, enzymes, acids, organs, and muscle movements all work together in an incredible system....