The primary gas found in Earth's atmosphere is nitrogen, comprising about 78% of the atmosphere by volume. Oxygen follows, making up about 21%. Nitrogen is essential for life, as it is a crucial component of amino acids and nucleic acids, which are fundamental to biological processes. The atmosphere also contains trace amounts of other gases, including carbon dioxide, argon, and water vapor. The balance of these gases is vital for maintaining life, regulating climate, and influencing weather patterns.