Final answer:
The most abundant gas in the air we breathe is nitrogen, comprising approximately 78% of the atmosphere, followed by oxygen at about 21%. The balance of these gases is essential for life on Earth.
Step-by-step explanation:
Most Abundant Gas in the Air
The most abundant gas in the air we breathe is nitrogen. Approximately 78% of the Earth's atmosphere consists of nitrogen, making it the primary component of air. The other significant component is oxygen, which constitutes about 21% of the atmosphere. The remaining 1% includes other gases such as argon, water vapor, and carbon dioxide, with carbon dioxide making up about 0.04%.
Although oxygen is essential for the process of aerobic respiration in living organisms, it is nitrogen that dominates our atmosphere. This balance of nitrogen and oxygen is critical for life on Earth as it prevents rapid combustion that could occur with higher oxygen levels. Additionally, nitrogen is a crucial element for living things as it is needed to make proteins, despite being in a form that most organisms cannot directly utilize.