Which of the following statements correctly describe(s) the role or roles of heat in biological reactions?

• A. Heat from the environment is necessary for substrates to get over the activation energy barrier.
• B. The kinetic energy of the substrates is increased as the amount of heat in the system is increased.
• C. Increasing the amount of heat in a system will always increase the rate of enzyme-catalyzed reactions.
• D. The second and third choices are correct.
• E. The first and second choices are correct.