1. Food changes in consistency and form when it travels through the digestive system, specifically the gastrointestinal (GI) tract, interacts with different enzymes, and experiences various mechanical and chemical processes. Teeth initiate this process as they physically break down the food into smaller and softer materials called bolus with the help of tongue chewing. It then turns into a chyme in the stomach as it mixes with digestive juices and continues to move and change through the other parts of the GI tract until it eventually becomes a stool.
2. The body can absorb nutrients from our foods via diffusion, facilitated diffusion, osmosis, and active transport, with 90% through the small intestine, assisted by its glands' fluid and mucus, circular fold, villi, and microvilli, and the other 10% through the stomach and large intestine.