Question

A student placed a sprig of green water plant under a funnel in a glass vessel full of water and then placed a test tube full of water mouth-downward over the stem of the funnel. After the setup had been exposed to sunlight for several hours, the student tested a gas that had collected in the test tube and concluded that the plant had produced oxygen. The results of this experiment could have been interpreted more satisfactorily if

Answer 1

(E) a similar experiment had been set up without sunlight.

Step-by-step explanation:

This would test the conclusion that the oxygen came from the plant. The plant would have produced oxygen through photosynthesis, which requires light. If we try this experiment again without using light we should see no oxygen show up. If oxygen did show up again, the oxygen must have come from somewhere else than the plant.