Will give brainliest

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 enlarge the chest cavity. they contract to pull your rib cage both upward and outward when you inhale.

"it built up in the atmosphere"

i think thats it, idk, i tried looking for this exact q& a for grad. and idk if i got this question right or sorry if im wrong