The light reactions require the cooperation of two photosystems to power linear electron flow from water to NADP+. Drag each item into the appropriate bin depending on whether the process is associated with Photosystem II (PS II) only, Photosystem I (PS I) only, or both PS II and PS I. Note that "electron transport chain" here refers to the electron transport chain between the two photosystems, not the one that functions after PS I.