What is the primary gas that makes up the Earth's atmosphere?

The primary gas that makes up the Earth's atmosphere is nitrogen, which comprises about 78% of the atmosphere by volume. This large percentage of nitrogen is significant because it plays a crucial role in various atmospheric processes and helps to regulate the overall composition of the air we breathe. While oxygen, carbon dioxide, and hydrogen are present in the atmosphere as well, they make up much smaller portions. Oxygen accounts for about 21% of the atmosphere, carbon dioxide is only about 0.04%, and hydrogen is found in trace amounts. Understanding the composition of the atmosphere is essential for studying weather patterns, climate change, and life on Earth.