The correct response is: The number of atoms of each element is the same on both sides.
This shows the law of conservation of mass, which states that mass is neither created nor destroyed in a chemical reaction. In the balanced equation \(4Fe + 3O_2 → 2Fe_2O_3\), the number of atoms of each element (iron and oxygen) is the same on both sides of the equation, indicating that the total mass remains constant throughout the reaction.