The opening and closing of stomata are due to:

The conversion of starch into organic acids is essential for:

Maximum water loss in plants takes place through which of the following?

Identify the purposes of transpiration.
$I -$ Transpiration creates a transpiration pull for absorption and transport in plants.
$II -$ It supplies water for photosynthesis.
$III -$ It transports minerals from the soil to all parts of the plant.
$IV -$ It cools leaf surfaces by $10-15^{\circ} C$ through evaporation.
$V -$ It maintains the shape and structure of plants by keeping cells turgid.

When do the stomata close?

According to the potassium pump theory of Levitt,which of the following statements is correct?