I think you're trying to refer to the mitochondria, though it is an organelle in itself, which is part of a cell. It's known as the "powerhouse of the cell" due to the process of cellular respiration, simplified as the way the cell acquires energy.
Answer: I think it's the third one: Letter Q points to the guard cell. Letter T points to the stomata and the response is most likely due to the humid tropical nature of the enviorment.
