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Humidity and Transpiration


Transpiration is the evaporation of water from open stomata in plant leaves. A group of AP Biology students used a gas pressure sensor in an experiment measuring transpiration. In an experiment testing the effect of humidity on the rate of transpiration, the following data was obtained.

Experimental Group Adjusted Rate $(k/Pa/min/cm^{2})$
A 0.1
B 1.5
C 5
D 17.2
E 25.3

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Which of the following identifies the group that was in the highest humidity condition?


Experimental Group A, since the adjusted rate shows minimal change in transpiration.


Experimental Group B, since this shows that some transpiration occurred, but at a low rate.


Experimental Group C, as the adjusted rate of water loss indicates an intermediate amount of transpiration.


Experimental Group E, since the highest rates of transpiration will occur with the greatest amount of evaporation.