Question

a mountain zone shows changes in vegetation as elevation increases. what physical factor most directly causes these changes? wind speeds decrease, allowing more plant growth at higher elevations. temperatures decrease and oxygen levels drop as elevation rises. less sunlight reaches the ground at higher elevations. soil nutrients increase at higher elevations.

Explanation:

As elevation increases, temperature decreases due to the decrease in air pressure and oxygen levels also drop. These factors directly affect vegetation. Wind speeds generally increase at higher elevations, not decrease. Sunlight availability is not the most direct factor here as it is not significantly reduced just due to elevation in most cases. Soil nutrients do not necessarily increase at higher elevations.

Answer:

Temperatures decrease and oxygen levels drop as elevation rises.