What is the most abundant permanent gas in the atmosphere, making up approximately 78%?

The most abundant permanent gas in the Earth's atmosphere is nitrogen, which constitutes about 78% of the atmosphere by volume. This gas is critical for various biological and chemical processes on Earth. Nitrogen is an inert gas under standard conditions, meaning it does not easily react with other substances, which contributes to its stability and abundance in the atmosphere.

In addition to being the primary component of air, nitrogen plays essential roles in biological systems, such as in the formation of amino acids and proteins, which are vital for all living organisms. Its prevalence facilitates the balance of gases in the atmosphere, allowing for the presence of oxygen and carbon dioxide, which are also necessary for life but in much smaller quantities. This understanding of nitrogen's abundance and role underscores why it is recognized as the most significant constituent of Earth's atmosphere.