A. The stratospheric ozone layer absorbs most of the sun's harmful ultraviolet (UV) radiation, protecting life on Earth. B. The scientific paper reporting the discovery of the Antarctic ozone hole by Farman, Gardiner, and Shanklin was published in Nature in May 1985. C. September 16th is internationally recognized as World Ozone Day, marking the date the Montreal Protocol on Substances that Deplete the Ozone Layer was signed in 1987. D. The Montreal Protocol, which came into effect in 1989, is an international treaty designed to phase out the production and consumption of ozone-depleting substances (ODS) such as CFCs and HCFCs.