Question

What allows air to flow into or out of the lungs?

Answer 1

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When you breathe in, or inhale, your diaphragm contracts (tightens) and moves downward. This increases the space in your chest cavity, into which your lungs expand. The intercostal muscles between your ribs also help enlarge the chest cavity. They contract to pull your rib cage both upward and outward when you inhale.

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Answer 2

air first go inside through nose dust particles is stick with hair and nostril further the change in gases take place at alveoli through small branch it pass through broncuole and then in alveoli change of gas take place when exhale CO2 came out through nose