Question

cyclic electron transport enhances atp production because: cyclic electron transport is more energy efficient than linear electron transport. excited electrons are transferred from ps i back to plastoquinone. photosystem i can pump more protons into the thylakoid lumen. the cycling of adp to atp is enhanced by transport. protons are recycled into the thylakoid lumen.

Explanation:

In cyclic electron transport in photosynthesis, excited electrons are transferred from Photosystem I (PS I) back to plastoquinone. This creates a proton - motive force that drives ATP synthesis. It doesn't involve the splitting of water or production of NADPH like linear electron transport. The transfer of electrons from PS I back to plastoquinone allows for additional proton pumping and thus enhances ATP production.

Answer:

excited electrons are transferred from PS I back to plastoquinone.