Use the diagram below to answer this question.
The structure that controls loss of water vapour during transpiration is labelled
A.
l
B.
ll
C.
lll
D.
lV
Correct answer is D
The stomata regulates gas exchange between the plant and environment and controls water loss by changing the size of the stomatal pore.
Guard cells are cells surrounding each stoma. They help to regulate the rate of transpiration by opening and closing the stomata.