Answer: Stratosphere.
- A Troposphere
- B Stratosphere
- C Mesosphere
- D Thermosphere
Correct answer: B. Stratosphere
Explanation: The ozone layer is found in the stratosphere, concentrated at about 23-25 km altitude. It absorbs harmful UV-B and UV-C radiation before it reaches Earth's surface. The troposphere lies below it and contains all weather phenomena.
Classical smog is a reducing mixture of SO₂ and fog, while photochemical smog is an oxidising mixture generated by UV-driven reactions of NOx and hydrocarbons.
Concept context
Understand how human activities alter the atmosphere, water, and soil. Covers air pollutants, smog types, ozone depletion, acid rain, greenhouse effect, water and soil pollution, and the principles of green chemistry.