Final answer:
Air pressure is the force exerted by the weight of air above a surface.
Step-by-step explanation:
Air pressure is the force that air exerts on a surface due to the weight of the air above it. It is caused by the collisions of air molecules with each other and with surfaces. The pressure of the air decreases as you go higher in the atmosphere due to the decrease in the number of air molecules above.
Learn more about Air pressure