I learned about a part of the Respiratory System called the chest and diaphragm. The diaphragm is located under your lungs and it makes your lungs expand and contract. Something really cool is that your lungs aren't made of muscles. They need your chest muscles and diaphragm to make air rush in and out of your lungs. When your diaphragm and chest muscles contract, air rushes in and fills up your lungs. When your diaphragm relaxes air rushes out and you breathe all of the air out of your lungs.

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