If cool air is more dense and sinks, what effect do you think that would have on air pressure on the ground? If warm air is less dense and rises, what effect do you think that has on air pressure on the ground?
there are 2 questions

Greater activity of the heated molecules increases the spacing between neighboring molecules and thus reduces air density. The decreasing air density then lowers the pressure exerted by the air. Warm air is thus lighter (less dense) than cold air and consequently exerts less pressure.

Explanation:

i really do want to but i just don't know it i'm so sorry : (

food chain i would say only because there is competition on getting food and survival