The opening and closing of the stomatal pore primarily depend on c) water in guard cells.
Explanation:
The guard cells, which surround the stomatal pore, change their shape depending on their water content. When water enters the guard cells, they swell, become turgid, and cause the stomatal pore to open. Conversely, when water leaves the guard cells, they become flaccid, leading to the closure of the stomatal pore.
Why other options are incorrect:
a) Oxygen:
While oxygen is important for respiration, it’s not directly involved in the opening and closing of stomata.
b) Temperature:
While temperature can influence transpiration, it’s not the primary factor controlling stomatal opening and closing.
d) Concentration of CO2 in stomata:
CO2 concentration can influence stomatal behavior, but it’s not the main factor. The primary factor is the water content within the guard cells.