Answer:
The correct option is 18
Explanation:
There are two reactant specie in the equation; carbon dioxide (CO₂) and water (H₂O). From the equation, there are 6 molecules of CO₂, hence the number of oxygen atoms from CO₂ is 6 × 2 = 12 and there are also 6 molecules of H₂O, hence the number of oxygen atoms from H₂O is 6 × 1 = 6.
The total number of oxygen atoms in the reactants is therefore 12 + 6 = 18
