That's because Earth's axis is tilted (as compared to a line that is perpendicular to Earth's plane of rotation). As a result, during part of the year, the northern hemisphere receives more sunlight; during another part of the year, the Southern Hemisphere receives more sunlight.
The earth has four seasons.
one
the rotation of the earth around the sun
The angle of the earth's tilt from the sun causes the Earth's seasons.
The earth is always orbiting the sun.
The dark season or night time.
along the equator
along the equator
along the equator
Because of how the earth rotates aroumd the sun.
Winter-
Summer