Answer:
The correct option is D. Enzymes reduce the activation energies of biological reactions.
Step-by-step explanation:
Enzymes are proteins that speed up the rate of a chemical reaction without being used up during the reaction. They are biological catalysts. Catalysts, as we know lower the activation energy for reactions and speed them up. The lower the activation energy for a reaction, the faster the rate. Thus enzymes speed up reactions by lowering activation energy which is option D.