[Campbell Biology P.238] Which statement best summarizes the process of gas exchange and tra... | Practice Question
Which statement best summarizes the process of gas exchange and transport in plant leaves, as described in the text?
A: Carbon dioxide enters the leaf and oxygen exits through microscopic pores called stomata, while veins transport water and sugar.
B: Water is absorbed by stomata and transported to the mesophyll cells, where CO2 and O2 exchange occurs.
C: The mesophyll tissue actively pumps CO2 into the leaf while O2 is released from the chloroplasts directly into the atmosphere.
D: Leaves export sugar to roots via microscopic pores, and water is absorbed from the atmosphere directly into the mesophyll.
Explanation
The text explicitly states: 'CO2 enters the leaf, and O2 exits, by way of microscopic pores called stomata.' It also mentions: 'Water absorbed by the roots is delivered to the leaves in veins. Leaves also use veins to export sugar to roots and other nonphotosynthetic parts of the plant.' This directly supports option A.