Maximum transpiration occurs in

$A$ metal ion involved in stomatal regulation is

In darkness,the stomata close because:

How much percentage of water is utilized for cell expansion and plant growth (in $\%$)?

When the relative humidity of the atmosphere is $100\%$ during the daytime,the stomata shall:

Arrange the events of opening stomata in correct sequence and choose the correct option accordingly.
$I.$ Lowering of osmotic potential of guard cells
$II.$ Decline in guard cell solute
$III.$ Rise of potassium ion level in guard cells
$IV.$ Guard cells absorb water from neighbouring epidermal cells
$V.$ Guard cells become flaccid
$VI.$ Guard cells swell and create a pore between them