Answer: CFCs (chlorofluorocarbons) from refrigerants and aerosols.
- A Carbon dioxide gradually released from the burning of fossil fuels worldwide
- B CFCs (chlorofluorocarbons) from refrigerants and aerosols
- C Methane gradually released from rice paddies and livestock farming operations
- D Nitrogen gas slowly accumulating within the upper stratosphere over decades
Correct answer: B. CFCs (chlorofluorocarbons) from refrigerants and aerosols
Explanation: CFCs (chlorofluorocarbons) release chlorine atoms in the stratosphere that catalytically destroy ozone: Cl + O<sub>3</sub> → ClO + O<sub>2</sub>. One chlorine atom can destroy 100,000 ozone molecules. The Montreal Protocol (1987) phased out CFCs globally.
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.