Reasons for the seasons

1. When it is winter in the northern hemisphere, the southern hemisphere gets the most concentrated light. When it is summer in the northern hemisphere, the northern hemisphere gets the most concentrated light.
2. When it is winter in the area  between the north pole and the equator, it is dark there and little light falls on it. When it is summer there, the most light is there 
3. If that happened, there would be the most light in the area in the squares 
4. The north and the south pole are the areas that are the coldest while the equator.
5. The shadow is the longest in the spring and the fall.
6. The more directly the light/heat hits the square, the more intense the heat/light are. For example, if the light/heat hit Earth directly level, at 180 degrees, it will be warmer than if it hits the Earth at 45 degrees.
7. The seasons exist because of the Earth's tilt. The tilt remains the same as the Earth moves around the Sun, so during some parts of the year, more light shines on the top of the Earth (northern hemisphere) and more light shines on the bottom of the Earth  during other parts of the year.