What is the main gas found in the Earth's atmosphere?

The main gas found in the Earth's atmosphere is nitrogen, which makes up approximately 78% of the atmosphere by volume. Nitrogen is an inert gas, meaning it does not readily react with other substances, and it plays a crucial role in maintaining the stability of the atmosphere. It acts as a buffer to more reactive gases, such as oxygen and carbon dioxide, which are present in smaller amounts. Understanding the composition of the atmosphere is important as it influences weather patterns, climate, and the overall environment in which life exists.