What is the primary gas found in Earth's atmosphere?

The primary gas found in Earth's atmosphere is nitrogen, which constitutes approximately 78% of the atmosphere by volume. This gas is crucial for various biological processes, including the nitrogen cycle, which all living organisms depend upon for growth and sustenance. Nitrogen does not readily react with other substances, making it a stable component in the atmosphere, and it plays a vital role in maintaining the overall composition of the air we breathe.

Oxygen, while essential for respiration in many organisms, is present in smaller quantities at about 21%. The remaining gases, including carbon dioxide and argon, exist in much lower concentrations. Carbon dioxide, although important in processes like photosynthesis and climate regulation, only composes about 0.04% of the atmosphere. Argon is the third most abundant gas but also makes up only about 0.93%. This highlights the dominance of nitrogen in Earth's atmospheric composition and emphasizes its importance in supporting life on Earth.