In stable atmospheric conditions, how does air behave?

In stable atmospheric conditions, air tends to remain stationary. This stability occurs when the air temperature increases with altitude, creating a situation where cooler, denser air resides closer to the surface and acts as a barrier to the rising of warmer air. Under these conditions, vertical movement is suppressed, preventing the air from lifting or descending. Instead, air parcels are limited in their vertical movement, leading to a stable atmosphere where air remains relatively still.

In contrast, options such as rising freely, descending slowly, or circulating rapidly would indicate an unstable atmosphere where air parcels could freely move due to convection processes, typically when warmer air at the surface rises, creating turbulence and circulation. Thus, in stable conditions, the air's behavior is characterized by a lack of significant movement, which is why remaining stationary is the accurate description.