The most abundant gas in Earth's atmosphere is nitrogen, which constitutes about 78% of the atmosphere by volume. Nitrogen is a colorless, odorless gas that plays a crucial role in various biological and environmental processes. While it is relatively inert and does not readily react with other substances, it is essential for life, as it is a key component of amino acids and nucleic acids. Nitrogen cycles through the ecosystem via processes such as nitrogen fixation and denitrification, impacting agriculture and natural ecosystems. The abundance of nitrogen helps maintain the atmospheric pressure and balance.