Answer:
The earth has seasons because of its tilted axis. The earth's axis is tilted by about 23.5 degrees relative to its orbit around the sun. This means that different parts of the earth receive different amounts of sunlight at different times of the year. When the earth's North Pole is tilted towards the sun, the Northern Hemisphere experiences summer, while the Southern Hemisphere experiences winter. When the earth's North Pole is tilted away from the sun, the Northern Hemisphere experiences winter, while the Southern Hemisphere experiences summer. The changing angle of the earth's axis relative to the sun causes the seasons to change throughout the year.