At sea level, what is the primary composition of the atmosphere?

• A. Oxygen
• B. Nitrogen
• C. Carbon Dioxide
• D. Argon

Answer: (B)

The primary composition of the atmosphere at sea level is nitrogen. Nitrogen makes up about 78% of the Earth's atmosphere, making it the most abundant gas present. This high concentration plays a crucial role in maintaining the overall stability and structure of the atmosphere, as nitrogen is inert and does not readily react with other substances.

Oxygen, which is vital for the respiration of most life forms, is the second most abundant gas, comprising about 21% of the atmosphere. While carbon dioxide and argon are present, their concentrations are significantly lower, with carbon dioxide making up about 0.04% and argon around 0.93%. Therefore, while oxygen, carbon dioxide, and argon are important for various processes, they do not constitute the primary component of the atmosphere at sea level. The dominance of nitrogen in atmospheric composition is fundamental to understanding various weather patterns and atmospheric dynamics.