Elodea is a plant that lives in water. Like all plants, elodea can make its own food through process called photosynthesis. Oxygen gas is also produced during photosynthesis.
Photosynthesis can only happen in the presence of light. To measure the rate of
photosynthesis, a piece of elodea can be placed in an inverted test tube filled with a
sodium bicarbonate solution. Oxygen gas produced by photosynthesis will collect at the
top of the test tube.
A student has designed an experiment using elodea plants. The experimental setup is
shown in Figure 1-4
Which of the setups would serve as the control of the experiment?
Bucket
Lamp
Flashlight High
Natural
Elodea
Sodium
bicarbonate
solution