Answer: photochemical smog.
- A acid rain
- B photochemical smog
- C the greenhouse effect
- D the ozone shield
Correct answer: B. photochemical smog
Explanation: Ozone in the troposphere is a pollutant and a key component of photochemical smog, unlike the good ozone in the stratosphere that shields us from UV rays.
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.