Revolution of the Earth around the Sun:
The changes in the seasons are primarily caused by the revolution of the Earth around the Sun. The Earth orbits around the Sun in an elliptical path, completing one full revolution in approximately 365.25 days. This movement is what determines the different seasons experienced in different parts of the world.

Key Points:
- The Earth's axis is tilted at an angle of approximately 23.5 degrees relative to its orbit around the Sun.
- As the Earth revolves around the Sun, different parts of the planet receive varying amounts of sunlight throughout the year.
- When a particular hemisphere is tilted towards the Sun, it experiences summer, characterized by longer days and warmer temperatures.
- Conversely, when that hemisphere is tilted away from the Sun, it experiences winter, with shorter days and colder temperatures.
- The equinoxes occur when the Earth's axis is neither tilted towards nor away from the Sun, resulting in equal lengths of day and night. This marks the beginning of spring and autumn.

Conclusion:
In conclusion, the changing of seasons is a result of the Earth's revolution around the Sun and the tilt of its axis. This phenomenon leads to the variation in sunlight received by different parts of the Earth, creating the distinct seasons we observe throughout the year.

Changes in the seasons are caused by:
The correct answer is D: Revolution of the earth around the sun.
Explanation:
The change in seasons is a result of the revolution of the earth around the sun. Here is a detailed explanation of how this process causes the seasons:
1. Revolution of the earth around the sun:
- The earth orbits the sun in an elliptical path.
- It takes approximately 365.25 days for the earth to complete one revolution around the sun.
- This revolution causes different parts of the earth to be tilted towards or away from the sun at different times of the year.
2. Tilt of the earth's axis:
- The earth's axis is tilted at an angle of about 23.5 degrees relative to its orbital plane.
- This tilt remains constant throughout the year, causing different hemispheres to receive different amounts of sunlight at different times.
3. Seasonal changes:
- When a hemisphere is tilted towards the sun, it experiences summer because the sunlight is more direct and concentrated in that area.
- As the earth continues its revolution, the hemisphere starts tilting away from the sun, leading to winter as the sunlight becomes less direct and spread out.
- The other hemisphere experiences opposite seasons due to the opposite tilt.
4. Effects of sunlight and darkness:
- The amount of sunlight received by a region affects its temperature and climate.
- During summer, longer daylight hours and more direct sunlight result in warmer temperatures.
- In contrast, shorter daylight hours and less direct sunlight during winter lead to colder temperatures.
In conclusion, the change in seasons is primarily caused by the revolution of the earth around the sun, which results in varying amounts and angles of sunlight reaching different parts of the earth throughout the year.