Which gases are considered permanent gases in the atmosphere?

• A. Nitrogen and Oxygen
• B. Carbon Dioxide and Methane
• C. Oxygen and Water Vapor
• D. Argon and Neon

Answer: (A)

The correct answer identifies nitrogen and oxygen as permanent gases in the atmosphere due to their consistent presence and relatively stable concentrations over time. These gases make up approximately 78% of the atmosphere as nitrogen and about 21% as oxygen, creating a stable mixture necessary for life on Earth.

In contrast, the other combinations include gases that either vary significantly in concentration or represent trace gases. Carbon dioxide and methane are considered variable gases as their levels fluctuate due to human and natural activities. Oxygen and water vapor also do not qualify as permanent gases since water vapor can vary widely in concentration depending on weather conditions. Argon and neon, while present in the atmosphere, are considered noble gases and do not play as significant a role in sustaining life as nitrogen and oxygen do. Thus, nitrogen and oxygen's stable and predominant presence in the atmosphere solidifies their classification as permanent gases.