The solution is as follows:
1. The ozone layer is present in stratosphere. It is very stable in lower temperatures which are present in stratophere.
2. Uses of ozone:
-It prevents harmful radiations from sun to enter the earth's atmosphere and radiate back UV radiations.
3. Freons are the major cause behind ozone layer depletion. We shall avoid using CFCs in compressors of AC, fridge and spraying agents so that they are not released in atmosphere and cause ozone layer to get depleted.