What happens to air pressure as altitude increases?

As altitude increases, air pressure decreases. This phenomenon occurs because the atmosphere is composed of layers of air, each exerting pressure on the layers below it. At higher altitudes, there are fewer air molecules above to exert pressure, leading to lower atmospheric pressure.

The density of air also diminishes with altitude. Since air pressure is a result of the weight of the air above a given point, as you rise in altitude, you are essentially reducing the column of air above you. This results in a decrease in air pressure. This relationship between altitude and air pressure is fundamental in meteorology and is a key aspect of understanding weather patterns and climate.

In contrast, the other options suggest stability or an increase in air pressure, which does not align with the observed behavior of the atmosphere as altitude changes. Atmospheric pressure is influenced by gravity pulling air molecules toward the Earth, causing higher pressure at lower altitudes and decreasing pressure with increasing height.