When levels of CO2 are experimentally increased, C3 plants generally respond with a greater increase in productivity than C4 plants. This is because
A)C3 plants are more efficient in their use of CO2.
B)C3 plants are able to obtain the same amount of CO2 by keeping their stomata open for shorter periods of time.
C)C4 plants don't use CO2 as their source of carbon.
D)C3 plants are more limited than C4 plants by CO2 availability because of transpirational water loss.
E)C3 plants have special adaptations for CO2 uptake, such as larger stomata.

Question

Quizplus · Accepted Answer

C3 plants are more limited by CO2 availability because they lose more water through transpiration when their stomata are open. Increased CO2 levels allow them to photosynthesize more efficiently without needing to open their stomata as much, reducing water loss.

When Levels of CO2 Are Experimentally Increased, C3 Plants Generally