What phenomenon causes the seasons on Earth?

• A. The tilt of Earth's axis as it orbits the Sun
• B. The distance from the Sun
• C. The rotation of the Earth
• D. The gravitational pull of the Moon

Answer: (A)

The seasons on Earth are primarily caused by the tilt of Earth's axis as it orbits the Sun. This axial tilt, which is approximately 23.5 degrees, means that different parts of the Earth receive varying amounts of sunlight throughout the year. During the summer solstice, one hemisphere is tilted toward the Sun, receiving more direct sunlight and experiencing warmer temperatures. Conversely, during the winter solstice, that same hemisphere is tilted away from the Sun, receiving less direct sunlight, leading to cooler temperatures.

This axial tilt is crucial because it is not the distance from the Sun that determines the seasons; rather, it is how the tilt affects sunlight distribution. As the Earth goes through its orbit, different regions are exposed to varying amounts of sunlight, creating the seasonal changes we experience. Thus, the correct understanding of how seasons work fundamentally revolves around this tilt rather than other factors like the Earth's rotation or the Moon's gravitational pull.