Stomata help in ...........

Phenylmercuric acetate $(PMA)$ results in which of the following effects?

Stomatal index $(I)$ is equal to:

Wilting and curling of leaves occur due to which factor?

Given below are two statements:
Statement $I$: The forces generated by transpiration can lift a xylem-sized column of water over $130 \text{ meters}$ in height.
Statement $II$: Transpiration cools leaf surfaces,sometimes by $10$ to $15$ degrees,through evaporative cooling.
In the light of the above statements,choose the most appropriate answer from the options given below:

By which process is the atmospheric temperature maintained?