Answer: Stratosphere (15-35 km altitude).
- A Troposphere (lowest atmosphere)
- B Stratosphere (15-35 km altitude)
- C Mesosphere
- D Exosphere
Correct answer: B. Stratosphere (15-35 km altitude)
Explanation: The ozone layer is in the stratosphere, primarily 15-35 km above Earth's surface. It absorbs 97-99% of harmful UV-B and UV-C radiation from the sun. Ozone hole forms over Antarctica each spring due to CFC-mediated destruction.
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.