dcpip (2,6-dichlorophenol-indophenol), a blue dye, can act as an electron acceptor and becomes colorless when reduced. a suspension of chloroplasts is prepared, and dcpip is added to the suspension. the sample is split into two test tubes. one test tube is exposed to light and the other is wrapped in foil (dark control). what would you observe over time comparing the light exposed and the dark control test tubes?