If the part of the plant underwater is somewhat sourcing oxygen from the water into dissolved oxy. (splitting H2O) while the part of the plant above water is converting carbon dioxide to oxygen, then it looks like there are two different operations going on, one in the bottom half and one in the top half of the plant to get the same results, free oxygen.
Neither portion of an emergent aquatic plant converts CO
2 into O
2. All photoautotrophs, including aquatic and terrestrial plants, convert some of their absorbed
water into free O
2. Although CO
2 contributes to the photosynthetic process, it isn't the source of the O
2 that is released by plants. Also, a plant (or portion thereof) doesn't need to live
in water in order to absorb water.
Also, if you take 2 parts H and one part O and put them into a test tube would you get water, or does it take an electric process like in a hydrogen car that gets the waste product of water.
Probably; but you might want to stand some distance away from the experiment.
Fission (splitting a nucleus) and
Fusion (combining nuclei) both release energy.
That's a different subject that I'm certainly not qualified to explain.
