If the equatorial plane of earth is NOT inclined to its orbit, then

* This tilt causes different parts of the Earth to be inclined towards or away from the Sun at different times of the year. When a hemisphere is tilted towards the Sun, it receives more direct sunlight and experiences summer. When it is tilted away, it receives less direct sunlight and experiences winter.
* If the equatorial plane of Earth were *not* inclined to its orbit (meaning the axial tilt was 0 degrees), the amount of sunlight received at any given latitude would be constant throughout the year. The Sun would always appear directly overhead at the equator at noon every day.
* This lack of variation in solar insolation across the year at different latitudes would mean there would be no distinct seasonal changes like summer, winter, spring, and autumn. The temperature and climate at any location would remain relatively stable year-round, primarily varying with latitude.
* Option A is incorrect because the duration of the year is determined by the time it takes for Earth to complete one orbit around the Sun (approximately 365.25 days), which is independent of the axial tilt.
* Options B and D are incorrect because summer and winter, as defined by varying temperatures and daylight hours caused by axial tilt, would not exist in their current form. While temperatures would vary by latitude, they wouldn’t follow the cyclical seasonal pattern caused by tilt.