Answer: carbon dioxide.
- A carbon dioxide
- B pure oxygen
- C pure nitrogen
- D pure argon
Correct answer: A. carbon dioxide
Explanation: Carbon dioxide is the principal greenhouse gas.
Sunlight passes through the atmosphere and warms the surface; the surface re-radiates this energy as infrared heat, which greenhouse gases (CO₂, CH₄, water vapour) absorb and trap - a naturally beneficial process that intensifies into global warming as gas concentrations rise from human activity.
Concept context
Pollution, global warming, ozone depletion, deforestation, and sustainability. Important for NEET and general awareness.