According to scientific theories, if enough cfc's are released into the the ozone layer will be depleted.

CFC molecules are broken down in the
stratosphere by ultraviolet light to give highly reactive chlorine atoms. Then chlorine atoms react with ozone molecules. Last chlorine atoms are regenerated by this chain reaction so can react with
more ozone molecules.

Your answer is  d.)relationship between pressure and air volume and led to the understanding of how respiration works