Brandon works on a livestock farm each day he takes his sheep grazing in the mountains he feels the air getting cooler as he climbs to the top of the mountain what is the best explanation for why the air gets cooler near the top

As Brandon climbs the mountain, he is getting into thinner and thinner air (air pressure is decreasing). All other things held constant, decreasing air pressure means decreasing temperature. As the air pressure decreases, particles get further apart and lose energy as they move about and collide into one another less and less frequently.