Explain5 marksStandard
A student investigated the effect of carbon dioxide concentration on the rate of photosynthesis in the aquatic plant Elodea canadensis. Shoots were placed in test tubes containing different concentrations of sodium hydrogencarbonate solution (which provides CO₂) and exposed to light from a lamp. The rate of photosynthesis was measured by counting the number of bubbles produced per minute. The experiment was repeated at two light intensities: low (lamp at 20 cm) and high (lamp at 10 cm). The results are shown in the table.
| CO₂ concentration (arbitrary units) | Rate at low light (bubbles per minute) | Rate at high light (bubbles per minute) |
|---|---|---|
| 0 | 0 | 0 |
| 2 | 5 | 8 |
| 4 | 10 | 16 |
| 6 | 12 | 24 |
| 8 | 12 | 30 |
| 10 | 12 | 32 |
Explain the results shown in the table. In your answer, identify the limiting factor(s) at different CO₂ concentrations for each light intensity.