Plants and Gas Concentrations?

Im new to these forums so hello to everyone here!

I hope im posting in the right place about this subject?

So im not very scientifically knowledgeable so my simple searches online are not resolving my curiosity :/ so i figured ill just ask the right people!

so....

1. Is the ONLY gas needed for leaves co2?

2. Is the ONLY gas needed for roots o2?

3. For both gases above if I were to mix them with a gas to get the right concentration, what gas would have no effect on the growth/chemistry and be easy to obtain?

Next im curious as to the general gas concentrations needed for roots/leaves. If this is a stupid question then please feel free to use a common plant as an example.

4. General % co2 needed for leaves during daytime/nightime

5. General % o2 needed for roots during daytime/nightime

6! If you were forced to just use co2 and o2 (plus other inert mixing gas) in the same grow chamber what % mix would you use during daytime/nightime? (considering the roots and leaves are in the same grow space with no medium and obstructions)

^^ most probably a stupid idea?!

Thanks for any usefull responses to my maybe silly questions!