Question

select the correct answer.

brandon works on a livestock farm. each day, he takes his sheep grazing in the mountains. he feels the air getting cooler as he climbs to the top of the mountain. what is the best explanation for why the air gets cooler near the top?

a. the amount of sunlight decreases near the mountaintop.

b. the amount of heat radiated from earths surface decreases with elevation.

c. cool air masses rise as they approach the base of the mountain.

d. there is a large body of water at the top of the mountain.

Explanation:

• Option A: Sunlight amount isn't the main reason for air cooling with elevation. The atmosphere is thin at higher altitudes, but the key is Earth's surface heat.
• Option B: Earth's surface radiates heat (from solar energy absorbed). As elevation increases, the distance from the surface (heat source) increases, so the heat radiated from the surface reaching higher altitudes decreases, leading to cooler air. This matches the phenomenon.
• Option C: Cool air is denser and sinks, while warm air rises. So this statement is incorrect.
• Option D: The problem doesn't mention a large body of water at the mountaintop, and this isn't a typical reason for mountain air cooling.

Answer:

B. The amount of heat radiated from Earth's surface decreases with elevation.