As altitude increases, what generally decreases?

As altitude increases, temperature generally decreases due to the atmospheric pressure changes and the thinning of air. This phenomenon is related to the adiabatic lapse rate, which describes how the temperature of air decreases as it rises and expands in the atmosphere. The reason for this cooling effect at higher elevations is primarily because the air becomes less dense, leading to reduced capacity for heat retention.

In contrast, while precipitation may vary with altitude due to factors like moisture availability and geographical features, it does not follow a consistent pattern of decreasing with altitude universally. Biodiversity tends to fluctuate based on habitat types and ecological niches at different elevations, and abiotic factors encompass a broader range of elements that do not uniformly decrease as altitude increases. Hence, the most direct and consistent relationship observed is the decrease in temperature with higher altitude.