Explanation:
you must add activation energy to initially break the chemical bonds. Catalysts simply lower the activation energy needed to do the chemical reaction going. reactions to occur without themselves being used up in the reaction. Energy is usually needed to break the bonds and get the reaction going.
Answer:
680
Explanation:
When the P680 special pair of photosystem II absorbs energy, it enters an excited (high-energy) state. Excited P680 is a good electron donor and can transfer its excited electron to the primary electron acceptor, pheophytin.