Changes in the seasons are caused by a. the tilt of Earth's axis toward or away from the sun. b. annual cycles of temperature and rainfall. c. variation in the distance between Earth and the sun. d. an annual cycle in the sun's energy output.

Verified step by step guidance

1. Identify the main factors that influence Earth's seasons. These include the tilt of Earth's axis and Earth's orbit around the sun.
2. Understand that the tilt of Earth's axis causes different parts of Earth to receive varying amounts of sunlight throughout the year, which leads to seasonal changes.
3. Consider how the tilt of Earth's axis might cause the northern and southern hemispheres to experience opposite seasons.
4. Evaluate whether changes in temperature, rainfall, the distance between Earth and the sun, or the sun's energy output directly cause the seasons to change.
5. Choose the option that best explains why different parts of Earth experience seasons at different times of the year.

Key Concepts

Tilt of Earth's Axis

The tilt of Earth's axis, approximately 23.5 degrees, is the primary reason for seasonal changes. As Earth orbits the sun, different hemispheres receive varying amounts of sunlight throughout the year, leading to the distinct seasons of spring, summer, autumn, and winter.

Earth's Orbit

Earth's elliptical orbit around the sun affects the distance between the two, but this variation is not significant enough to cause seasonal changes. Instead, the axial tilt plays a more critical role in determining the intensity and duration of sunlight received in different regions.

Solar Energy Output

While the sun's energy output does fluctuate slightly over time, these changes occur over much longer cycles and do not directly cause the seasonal variations experienced on Earth. Seasonal changes are primarily driven by the axial tilt rather than variations in solar energy.