Answer:
air pressure
Step-by-step explanation:
The diagram shows the concept of air pressure. Air pressure is also called atmospheric pressure. The pressure which is applied by the gases present above in the atmosphere on the object present below on the surface of earth. Atmospheric pressure is measured by an instrument called barometer. One atmosphere is equals to 1,013 millibars, or 760 millimetres of mercury. At sea level, air pressure is maximum while on hilly areas, this air pressure becomes lower due to less gases in the atmosphere.