Oxygen is the only element in the list.
Answer: Boyle's Law
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Boyle's Law is the pressure-volume law and it relates pressure and volume at constant temperature. Boyle's law states that pressure and volume vary inversely, meaning that as one goes up, the other one goes down.
That wouod be the ionosphere!
Well, I think it's mainly for photosynthesis and gas exchange. A leaf is normally flat, light, and thin, so that the sunlight can get to the chloroplasts in the cells.