Isotopes Mg-24,Mg-25 and Mg-26 has natural abundance of 79.0%,10.0% and 11.0%. Calculate the relative atomic mass for isotopes Mg-24,Mg-25 and Mg-26. Please help me with with this question

The equation below shows a chemical reaction. a + b + heat —> c + d according to the law of conservation of energy, which statement is true? a. the reactants absorb heat because they have less energy than the products. b. the products release heat because they have more energy than the reactants. c. the reactants generate heat because they have more energy than the products. d. the products require heat to form because they have less energy than the reactants.