Answer:
Question: Why is it necessary for us to breathe in oxygen (O2) and breathe out carbon dioxide (CO2)?
Answer:
Oxygen helps our cells work harder by breaking down the nutrients we get from food like sugars. With sugars and oxygen, our cells can create the energy they need to function. This process also produces carbon dioxide. The carbon dioxide produced is a waste product and needs to be removed.
#READYTOHELP
