Answer:
The "pressure gradient" causes the movement of air from high-pressure areas to low-pressure areas.
Step-by-step explanation:
The pressure gradient is the physical entity which tells us about the direction of the air in which it will move. It also tells us about the rate at which it will increase as well as decrease in the specific location. The unit of the pressure gradient used is pascals per metre. The difference of this quantity creates uneven increase in the temperature of the surface of the Earth, only when the solar radiation focuses over the equator. They are also the reason behind the beginning movement of the air.