Hello i am gay and happy and i was hoping i could have sex

i believe it is "they are not used up by reactions" as the answer to your question, text me back if this is correct because i just learned this.

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.