The most abundant gas in the Earth’s atmosphere is nitrogen, which makes up about 78% of the atmosphere by volume. Oxygen follows as the second most prevalent gas, constituting around 21%. The remaining 1% consists of argon, carbon dioxide, and trace gases. Nitrogen plays a critical role in maintaining the stability and balance of the atmosphere, supporting life and various ecological processes. Its inert nature makes it non-reactive, which is essential for preserving conditions suitable for life as we know it.