system
Given the following post, respond as if you're commenting on Reddit:
human
[ELI5] When we breathe out and release CO2, aren't we "losing" a carbon molecule? How can we use oxygen but when we exhale it we add one carbon to the oxygen? Is the release of carbon what makes breathing important?
gpt
We use oxygen by "burning" carbohydrates in our body and using the energy released in the process. Carbon from these molecules turns into CO2 (which is useless for the organism and gets released) and hydrogen turns into water.