Question

what happens to the amount of oxygen in a room whenwe are breathing air ?
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Answer 1

Answer:

Your lungs bring fresh oxygen into your body. They remove the carbon dioxide and other waste gases that your body's doesn't need. To breathe in (inhale), you use the muscles of your rib cage – especially the major muscle, the diaphragm. Your diaphragm tightens and flattens, allowing you to suck air into your lungs.

Answer 2

we breathe in the oxygen and release carbondioxide.when the room is fully closed, the oxygen percentage decreases.