What is the primary component of Earth's atmosphere?

The primary component of Earth's atmosphere is nitrogen, which makes up approximately 78% of the atmosphere's composition. This significant proportion plays a crucial role in various processes. For example, nitrogen is largely inert, meaning it does not readily react with other chemicals in the atmosphere, allowing other processes, such as the growth of plants through photosynthesis, to take place.

While oxygen is essential for life and accounts for around 21% of the atmosphere, it is not the dominant gas. Carbon dioxide and argon are present in much smaller amounts, with carbon dioxide contributing to the greenhouse effect and argon being a noble gas that has minimal reactivity. Understanding nitrogen's predominance in the atmosphere is critical not only in the context of earth science but also when discussing topics such as air quality, climate change, and ecology.