When you breathe in, what goes into your lungs?
Oxygen
When you breathe out, what goes back into the air?
Carbon dioxide
To make water, air, gas, etc. flow in a particular direction by using a pump or something that works like a pump
pump
To take air into your lungs and send it out again through your nose or mouth
breathe
Two parts inside in the chest that you use for breathing
lungs
The red liquid that goes around your body and keeps you alive
blood
