Question

which of the following best describes why we have seasons on earth?
○ the tilt of earths axis causes different portions of the earth to receive more or less direct sunlight at different times of year.
○ earths elliptical orbit means we are closer to the sun and therefore receive more intense sunlight at some times of year than at others.
○ the varying speed of earth in its orbit around the sun gives us summer when we are moving fastest and winter when we are moving slowest.
○ the suns total energy output varies throughout the year and is greatest during the summer and least during the winter.
○ the tilt of earths axis causes the northern hemisphere to be closer to the sun than the southern hemisphere in summer, and visa versa in winter.

Explanation:

• Option 1: Earth's axis is tilted (~23.5°). As Earth orbits the Sun, different hemispheres get more/less direct sunlight. Direct sunlight heats the surface more, causing seasons.
• Option 2: Earth's elliptical orbit's distance change is minimal (about 3 million miles) and not the main reason for seasons.
• Option 3: Earth's orbital speed (Kepler's laws) relates to distance, not season creation.
• Option 4: The Sun's energy output is relatively constant over a year; seasonal changes in sunlight on Earth are due to Earth's tilt, not Sun's output.
• Option 5: Earth's axis tilt does not make hemispheres significantly closer/farther from the Sun (distance change is negligible compared to tilt's effect on sunlight angle).

Answer:

The tilt of Earth's axis causes different portions of the Earth to receive more or less direct sunlight at different times of year.