With reference to 'ozone layer', which of the following statements is/are correct?1.Ozone layer shields the surface of the earth from the ultra-violet radiations from the sun.2.Ozone depletion has been linked to the chlorofluorocarbons.Select the correct answer from the code given below:

1. A

   Only 2

   Only 2. The UV-shield limb is also keyed.

2. B

   Neither 1 nor 2

   Neither. Both textbook lines hold.

3. C

   Both 1 and 2

   Both 1 and 2. Stratospheric ozone blocks solar UV. CFCs (and related halocarbons) drive ozone depletion.

4. D

   Only 1

   Only 1. The CFC link is also keyed.

Summary. Official key is (c) both. Ozone shields UV; CFCs are linked to depletion. Also note: Dobson unit — Ozone-column measure; Montreal Protocol 1987 — CFC phase-out; Antarctic hole — Spring polar depletion; Tropospheric O3 — Pollutant; not this shield.