Concept:The Earth's orbit around the Sun changes the angle and duration of sunlight received in different hemispheres.Explanation:The Earth takes about 365¼ days to revolve once around the Sun.During this journey, the Earth's axis is tilted, so different parts of the Earth receive more direct sunlight at different times of the year.This variation in sunlight causes the four seasons: spring, summer, autumn, and winter.Answer:C. the four seasons.