Why do we breathe in oxygen and exhale carbon dioxide?
A. Oxygen is a product of cellular respiration.
B. Both gases are produced during cellular
respiration.
C. Oxygen is required to start cellular
respiration, and carbon dioxide is a product.

When we take a breath, we pull air into our lungs that contains mostly nitrogen and oxygen. When we exhale, we breathe out mostly carbon dioxide. ... 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.

Explanation:

c

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explanation:

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