Final answer:
In all redox reactions, both charge and mass are conserved.
Step-by-step explanation:
In all redox reactions, both charge and mass are conserved. This means that the sum of the mass numbers of the reactants equals the sum of the mass numbers of the products, and the sum of the charges of the reactants equals the sum of the charges of the products.
For example, in the equation: 2Mg + O₂ → 2MgO, the mass and charge of the reactants (2Mg + O₂) is equal to the mass and charge of the products (2MgO). Therefore, the correct answer is option 1) both charge and mass.