The thin layer of gases surrounding the earth is called the atmosphere. It contains 78% nitrogen, 21% oxygen, 0.03% carbon dioxide, 0.9% argon and traces of other gases. Water vapour, dust particles and other solid particles are also found in the atmosphere. Thus, correct option is b)atmosphere.

The Gaseous Layer of the Earth: The Atmosphere

The gaseous layer of the Earth is known as the atmosphere. It is a critical component of our planet and plays a vital role in supporting life. The atmosphere is composed of various gases, such as nitrogen, oxygen, carbon dioxide, and trace amounts of other gases.

Key Points:
- The atmosphere is the layer of gases that surrounds the Earth.
- It extends up to several hundred kilometers above the Earth's surface.
- The atmosphere is divided into different layers based on temperature and composition.
- The main gases in the atmosphere are nitrogen (78%) and oxygen (21%).
- Other gases, including carbon dioxide, water vapor, and trace gases, are present in smaller amounts.

Importance of the Atmosphere:
- The atmosphere provides a protective shield around the Earth, shielding us from harmful radiation and meteoroids.
- It regulates the Earth's temperature by trapping heat and preventing extreme temperature fluctuations.
- The atmosphere is essential for the water cycle, as it contains water vapor that condenses to form clouds and eventually precipitation.
- It plays a crucial role in supporting life on Earth by providing oxygen for respiration and carbon dioxide for photosynthesis.
- The atmosphere also helps distribute heat around the globe, leading to weather patterns and climate variations.

Layers of the Atmosphere:
The atmosphere is divided into several layers based on temperature changes with increasing altitude. These layers include:
1. Troposphere: The lowest layer, where weather phenomena occur and temperature decreases with altitude.
2. Stratosphere: Contains the ozone layer, which absorbs harmful ultraviolet radiation. Temperature increases with altitude.
3. Mesosphere: The middle layer where temperature decreases with altitude. Meteors burn up in this layer.
4. Thermosphere: The uppermost layer where temperature increases with altitude. It contains the ionosphere, crucial for radio communication.
5. Exosphere: The outermost layer, where the atmosphere gradually merges with space.

Conclusion:
The gaseous layer of the Earth, known as the atmosphere, is crucial for supporting life and regulating the planet's climate. It plays a vital role in protecting us, distributing heat, and facilitating various natural processes. Understanding the atmosphere and its composition is essential for comprehending Earth's complex systems.