The digestive system breaks down food and transforms nutrients into energy through a multi-step process. Food enters the mouth where it is broken into smaller pieces by teeth and travels to the stomach through the esophagus. In the stomach, food is further broken down by enzymes and mixed. Nutrients are then absorbed through the small intestine and large intestine, with waste expelled through the rectum and anus. The digestive system provides energy to cells and allows the body to eliminate waste.