Combustion reaction
Key: O2
O2 is normally in a chemical formula when you are used to burn anything, so basically, anything with O2 involves burning.
Plants use energy from the Sun to trigger photosynthesis carbon dioxide pulled from the air and water drawn from the roots is converted to sugar to be used wright away or to be stored the longer the day the more food can be produced
The correct answer would be equation 4, because there are 4 Hydrogens and 2 Oxygens on each side of the equation making it balanced.
