Question

enzymes affect the reactions in living cells by changing the
o types of atoms in the reaction
speed of the reaction.
temperature of the reaction.

Explanation:

Enzymes are biological catalysts. Catalysts, in general, work by lowering the activation energy of a reaction, which in turn affects the speed at which the reaction occurs. Temperature can also affect reaction speed (as enzymes have an optimal temperature range), but the direct and primary way enzymes act is by influencing the reaction speed. The types of atoms in a reaction are determined by the reactants and are not changed by the enzyme (enzymes are not consumed in the reaction and do not alter the elemental composition of reactants).

Answer:

speed of the reaction.