The predominant gas in the Earth's atmosphere is nitrogen, which makes up about 78% of the atmosphere. Oxygen follows at approximately 21%, while the remaining 1% consists of argon, carbon dioxide, and other gases in trace amounts. This atmospheric composition is crucial for supporting life as we know it, with nitrogen being inert and serving as a stable background element, while oxygen is essential for respiration in most living organisms. The maintenance of this gas mixture enables various ecological and atmospheric processes, including weather patterns and the greenhouse effect, which together sustain the climate on Earth.