What causes opening of stomata
(a) Thin wall of guard cell facing stomatal pore is stretched more, curves in and the pore opens.
(b) Thick wall of guard cell facing stomatal pore is stretched more, moves in and pore opens.
(c) As thin wall of guard cell is stretched less, the guard cell wall facing the stomatal pore moves in and pore opens.
(d) Thick wall of guard cell facing the stomatal pore is strectched less, moves, in and the pore opens.