What happens if a plant in a potometer is kept under a fan or in bright light? The bubble of the potometer would:

How the change in $pH$ occurs in guard cells was explained and the theory of starch $\rightleftharpoons$ sugar interconversion was proposed by:

Give differences between the stomata of monocot and dicot plants.

Guttation is caused due to

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:

Water moves up against gravity and even for a tree of $20 \,m$ height, the tip receives water within two hours. The most important physiological phenomenon which is responsible for the upward movement of water is $...........$