Answer: SO 2 and NOx reacting with water to form H 2 SO 4 and HNO 3.
- A A gradual buildup of excess atmospheric carbon dioxide alone
- B SO<sub>2</sub> and NOx reacting with water to form H<sub>2</sub>SO<sub>4</sub> and HNO<sub>3</sub>
- C Gradual depletion of the protective stratospheric ozone layer
- D Heavy metal contamination accumulating gradually within rainwater
Correct answer: B. SO<sub>2</sub> and NOx reacting with water to form H<sub>2</sub>SO<sub>4</sub> and HNO<sub>3</sub>
Explanation: Acid rain: SO<sub>2</sub> and NOx (from burning fossil fuels) react with water vapor to form sulfuric and nitric acids in rain.
Concept context
Levels of biodiversity, species richness patterns, threats (HIPPO), and conservation strategies. Always in NEET.