Why does the air at higher pressure move downward?

The instructions for making proteins come originally from

The solution inside a plant cell is approximately a 1% saline solution and a 21% nacl solution the ,cytoplasm of a plant cell will

On a spring day, a middle-latitude city (about 40? north latitude) has a surface (sea-level) temperature of 10 ? c. if vertical soundings reveal a nearly constant environmental lapse rate of 6.5 ? c per kilometer and a temperature at the tropopause of –55 ? c, what is the height of the tropopause?