Contrary to grandparent, in oxygenic photosynthesis, the oxygen does come from splitting water. The resulting hydride used to "charge" an electron carrier: https://en.wikipedia.org/wiki/Photodissociation#Photolysis_i...
The CO2 gets fixed into carbohydrates. Some water is generated in that process, but no molecular oxygen.
Contrary to grandparent, in oxygenic photosynthesis, the oxygen does come from splitting water. The resulting hydride used to "charge" an electron carrier: https://en.wikipedia.org/wiki/Photodissociation#Photolysis_i...
The CO2 gets fixed into carbohydrates. Some water is generated in that process, but no molecular oxygen.