Cellular respiration describes the process that living cells use to release energy by combining sugar and oxygen. the primary chemical changes that happen during cellular respiration are shown in the equation below. which statement correctly compares the reactants and products of the equation? a. the mass of the reactants is the same as the mass of the products. b. the number of reactant atoms is greater than the number of product atoms. c. the mass of the reactants is less than the mass of the products. d. the number of reactant atoms is less than the number of product atoms.