Which gas is most abundant in the Earth's atmosphere, making up 78%?

The most abundant gas in the Earth's atmosphere, making up about 78% of it, is nitrogen. This gas is essential for several biological processes and plays a key role in the formation of proteins and nucleic acids, which are vital for life. Nitrogen is relatively inert, meaning it does not easily react with other substances, which helps maintain the stability of the atmosphere. While oxygen and carbon dioxide are important as well, they are present in significantly smaller amounts, with oxygen at about 21% and carbon dioxide at a fraction of a percent. Argon, while also a component of the atmosphere, constitutes only about 0.93% of it. This understanding of atmospheric composition is crucial for studies related to environmental science, meteorology, and biology.