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 swells and make a pore between them
a)	III, I, IV, V	b)	I, II, III, IV, V, VI	c)	III, I, IV, VI	d)	III, I, IV, VI, II, V

(c)

According to active  theory of Levitt, the stomatal opening and closing is regulated by ATP driven  exchange pump. According to this theory, there is a accumulation of  in the guard cells during day time 200. When guard cells have more , endosmosis takes place, resulting in the lowering of osmotic potential of guard cells. They starts to absorb water from neighbouring cells and becomes turgid to make a pore or opening in the stoma.

Thus, stomatal opening takes place. Due to the loss of  the osmotic concentration of guard cells in comparison to adjoining epidermal cells decreases. Therefore, exosmosis takes place and guard cells becomes flaccid due to the loss of turgidity. Thus, stomatal closure takes place