What's the hardest part of your body? It's not your bones or your fingernails. It's your teeth. Teeth need to be strong because they chew up all the food you eat.
When you chew your food, digestion begins. During this process, the bits of food you swallow travel to your stomach. Chemicals in your stomach break down the bits into even smaller particles called nutrients. Next, the nutrients move into your small intestine, where they enter your blood vessels. Your blood then carries the nutrients to the rest of your body, so they can help you breathe, flex muscles, and think during tests.