Consider the following statements about ozone gas:

1.CFCs release halogen radicals that deplete the ozone layer and cause health, food and water problems

2.Surface ozone forms when heat and sunlight react nitrogen oxides with volatile organic compounds

3.Transport-sector ozone is harmful while stratospheric ozone is protective

4.Many adverse effects of high UV exposure have been avoided due to the Montreal Protocol

AStatements 2, 3 and 4 are correct

BStatements 1, 3 and 4 are correct

CStatements 1, 2 and 3 are correct

DStatements 1, 2, 3 and 4 are correct ✓ Correct

Correct answer: (D) Statements 1, 2, 3 and 4 are correct

Explanation

Statement 1 is correct, as chlorofluorocarbons release halogen radicals that deplete the ozone layer and bring health, food and water problems.

Statement 2 is correct, since surface ozone forms when heat and sunlight make nitrogen oxides react with volatile organic compounds.

Statement 3 is correct, as ground-level ozone from transport is harmful while stratospheric ozone is protective.

Statement 4 is correct, since the Montreal Protocol has averted many harmful effects of high ultraviolet exposure.

All four statements therefore hold true.

The Montreal Protocol of 1987 is credited with putting the ozone layer on a path to recovery.

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