Refer to the graph below showing results from experiments in which uptake of carbon dioxide by a leaf was measured as the leaf was irradiated with different quantities of light.The experiments were repeated at different levels of carbon dioxide in the air surrounding the leaf, to give the three curves. The rate of photosynthesis is increased at all three levels of carbon dioxide.Which causes are consistent with these data?
A) Increases in both light and carbon dioxide
B) Decreases in both light and carbon dioxide
C) Increases in light and decreases in carbon dioxide
D) Increases in carbon dioxide and decreases in light
E) Increases in light only

Question

Refer to the graph below showing results from experiments in which uptake of carbon dioxide by a leaf was measured as the leaf was irradiated with different quantities of light.The experiments were repeated at different levels of carbon dioxide in the air surrounding the leaf, to give the three curves.  The rate of photosynthesis is increased at all three levels of carbon dioxide.Which causes are consistent with these data?
A) Increases in both light and carbon dioxide 
B) Decreases in both light and carbon dioxide 
C) Increases in light and decreases in carbon dioxide 
D) Increases in carbon dioxide and decreases in light 
E) Increases in light only

Quizplus · Accepted Answer

The graph shows that as the quantity of light increases, the rate of photosynthesis (uptake of carbon dioxide by the leaf) also increases. Additionally, at all three levels of carbon dioxide, there is an increase in the rate of photosynthesis as the light intensity increases. This suggests that increases in light are a consistent cause of the observed increase in photosynthesis. Furthermore, the fact that the rate of photosynthesis is greater at higher levels of carbon dioxide supports the idea that increases in carbon dioxide also contribute to the observed increase in photosynthesis. Therefore, the data are consistent with increases in both light and carbon dioxide being causes of the increase in photosynthesis.

Refer to the Graph Below Showing Results from Experiments in Which