The opening and closing of the stomatal pore depends upon
(a) oxygen
(b) temperature
(c) water in guard cells
(d) concentration of CO2 in stomata
Closing and opening of guard cells depends on the water content in the cells. If there is water in the cells the pores get opened and if there is less water, the cell shrinks and the pore gets closed. Hence, (c) is the correct option.