Two sealed test-tubes that each contained aquatic plants and hydrogencarbonate indicator were prepared. One sealed test-tube was left in the light for 24 hours, while the other was left in the dark for 24 hours. The indicator indicates the concentration of dissolved carbon dioxide present. At the beginning, both test-tubes were orange. After 24 hours, the test-tube kept in the light had turned red and the test-tube kept in the dark had turned yellow. What is the correct explanation of what happened?
- APhotosynthesis and respiration both occur in the light, but the rate of photosynthesis is higher.
- BPhotosynthesis occurs in the light, but respiration does not.
- CRespiration can only occur when photosynthesis is not taking place.
- DThe amount of carbon dioxide used and produced in the light is equal.