Composition of the Atmosphere:
The atmosphere is a layer of gases that surrounds the Earth. It is composed of various gases, particles, and water vapor. The composition of the atmosphere can be divided into two main categories: permanent gases and variable gases.

Permanent Gases:
Permanent gases are those gases that are present in the atmosphere in relatively constant proportions. The major permanent gases in the atmosphere are:

1. Nitrogen (N2): It is the most abundant gas in the atmosphere, making up about 78% of the total volume. Nitrogen is essential for the growth of plants and animals.

2. Oxygen (O2): Oxygen is the second most abundant gas in the atmosphere, accounting for about 21% of the total volume. It is necessary for the respiration of organisms, combustion, and various chemical reactions.

3. Argon (Ar): Argon is a noble gas and is present in the atmosphere in small quantities, about 0.93%. It is non-reactive and does not participate in chemical reactions.

4. Neon (Ne), Helium (He), Krypton (Kr), and Xenon (Xe): These are other noble gases that are present in trace amounts in the atmosphere.

Variable Gases:
Variable gases are those gases that exist in the atmosphere in varying amounts depending on factors such as location, season, and human activities. The major variable gases in the atmosphere are:

1. Carbon Dioxide (CO2): Carbon dioxide is an important greenhouse gas that plays a significant role in the Earth's climate. Its concentration has been increasing due to human activities such as burning fossil fuels and deforestation.

2. Methane (CH4): Methane is another greenhouse gas that is released through natural processes like wetlands and human activities such as livestock farming and rice cultivation.

3. Ozone (O3): Ozone is present in the atmosphere in two layers: the troposphere and the stratosphere. In the stratosphere, it forms the ozone layer, which protects the Earth from harmful ultraviolet (UV) radiation.

4. Water Vapor (H2O): Water vapor is the gaseous form of water and is present in varying amounts in the atmosphere. It plays a crucial role in weather and climate processes.

Diagram:
Unfortunately, as a text-based AI, I am unable to provide diagrams. However, you can find informative diagrams illustrating the composition of the atmosphere in many geography textbooks or educational websites such as EduRev. These diagrams typically show the relative proportions of the different gases in the atmosphere.