The amount of insolation decreases from the Equator towards the Poles. What is the primary reason for this?
Options
The Earth's rotation causes the sun's rays to be more direct at the poles.
The angle of the sun's rays becomes more oblique (slanted) as one moves away from the Equator.
The presence of more clouds near the Poles blocks sunlight.
The Earth's magnetic field deflects more sunlight at higher latitudes.
Explanation
Insolation, or incoming solar radiation, decreases from the Equator towards the Poles because the sun's rays strike the Earth's surface more directly at the Equator. As one moves towards the Poles, the angle of the sun's rays becomes increasingly oblique or slanted. This means the same amount of solar energy is spread over a larger area, reducing its intensity and leading to lower temperatures. Therefore, option B is correct. The other options describe incorrect or less significant factors.