Answer:
Carbon dioxide is a byproduct of the respiratory system.
Explanation:
We know that our respiratory system helps bring oxygen into our body for our cells to use for cellular respiration. Without oxygen, we would only have fermentation as our only option to create energy.
We know that during the process of cellular respiration (aka Krebs Cycle and Electron Transport Chain), oxygen is taken in and used, creating energy (ATP) and carbon dioxide.
Carbon dioxide is a byproduct and must be removed from the body because it can't be used in cellular respiration.
The respiratory system takes that carbon dioxide and removes it from the body.
The respiratory system works by taking in oxygen (inhaling) and removing carbon dioxide (exhaling).
