What happens to pressure as altitude increases?

As altitude increases, the pressure decreases. This phenomenon occurs due to the thinning of the atmosphere as you go higher above sea level. The density of air diminishes with elevation, leading to fewer air molecules exerting force on a given area, which results in lower atmospheric pressure.

In the atmosphere, the weight of the air above you decreases as you climb, thus lowering the pressure. This principle is fundamental in meteorology and is crucial for pilots to understand, as it affects aircraft performance and weather systems.

The incorrect options do not align with the established principles of atmospheric science. The idea that pressure remains unchanged contradicts the fundamental behavior of gases under varying conditions. Similarly, the notion that pressure increases with altitude is entirely opposite to observed atmospheric behavior. Lastly, the concept of pressure fluctuating unpredictably does not hold true; while short-term fluctuations in weather can occur, the overall trend is a consistent decrease with altitude under normal circumstances.