(4) Which best explains why Earth is colder at the poles than at the equator? A. Earth is farther from the Sun at the poles than at the equator. B. Earth's orbit is not a perfect circle. C. Earth's rotation axis is tilted. D. Earth's surface is more tilted at the poles than at the equator.

The answer is C. Earth's rotation axis is tilted. This tilt causes sunlight to hit the poles at a more oblique angle, spreading the energy over a larger area and reducing the warmth compared to the direct sunlight received at the equator, where the rays are more perpendicular. Understanding this concept can also help us appreciate why polar regions experience extreme seasonal variations, with long days in summer and extended darkness in winter, while the equatorial regions enjoy more consistent daylight year-round, affecting climate, ecosystems, and human activities in these diverse regions!