Question: How would you react if there was no more oxygen in the world?

If oxygen was truly absent – we’d not be able to breathe and would die.
Oxygen is present in many chemical compounds, but we need to inhale it as a gas.
To help life on earth to breathe, the most common method of oxygen creation is photosynthesis whereby plants use sunlight convert carbon dioxide in the air into oxygen. The more trees we plant (and the fewer we cut down for wood or sap), the more oxygen will be available for the world.
One method that we can use to create create oxygen artificially is by electrolysis – using electricity to separate water into it’s constituent parts: hydrogen from oxygen.