The correct answer is option 3: Pressure. In Earth`s atmosphere, pressure decreases with increasing altitude. This is because the weight of the air above decreases as you go higher, resulting in lower atmospheric pressure. The air molecules get less crowded as you go higher, which leads to a decrease in pressure. Temperature does not continuously decrease with height; it actually varies depending on factors such as the altitude, latitude, and time of day. Humidity can also vary with altitude, depending on the amount of water vapor present in the air. Wind velocity can change with height, depending on factors such as air temperature gradients and atmospheric circulation patterns. Therefore, while the options may be interrelated, the only option that continuously decreases with height is pressure.