Answer:
from the splitting of water molecule.
Step-by-step explanation:
The splitting of water molecules by sunlight is called Photolysis. This is the first reaction in photosynthesis; which occurs by catalysis of enzymes of Photo system 11.
It involves the splitting of water molecules into;
hydrogen ion/protons.
Oxygen
and electron.
Oxygen is the by product liberated into the atmosphere, for animals to inhale for the process of cellular respiration.This is the source of oxygen fro cellular respiration in animals.
the hydrogen ions combined with electrons from photosystem 1 to reduce NADP .The latter is used to reduce C02 to form carbohydrate in light independent reaction