If a chemical reaction catalyzed by an enzyme is being carried out, and there is a sudden, drastic decrease in temperature, what is most likely to happen next? . a. enzyme activity will decrease, and the reaction will proceed very slowly, or possibly not at all.. b. less heat will be lost to the environment, and the reaction will take place more efficiently.. c. the reaction will proceed more quickly since the activation energy is decreased.. d. the reaction rate will decrease and eventually return to normal as the enzyme adapts to the temperature change.