To determine whether carbon dioxide is essential for photosynthesis, a plant was watered with carbon dioxide-free water and placed in the apparatus shown in the diagram. The setup was kept in darkness for 24 hours to remove starch from the leaves.
After several hours of exposure to light, a leaf was taken from the plant and tested for starch, but none was detected. A control experiment was conducted using a second plant, where a leaf tested positive for starch.
Describe the control for this experiment.
a.
b.
c.
Outline how the carbon dioxide could be removed from the water used to irrigate the plant.
can be removed from water by:
a. boiling (and cooling) the water
b. expose the water to a vacuum
Suggest how a plastic bag placed around the plant pot would prevent carbon dioxide from reaching the plant's leaves.
a.
b.
