Answer:A) Can form ozone and block some UV radiation
Explanation: Ozone layer is made up of three oxygen atoms,it is formed as a result of the break down of oxygen in the high atmosphere by Ultraviolet radiation from the Sun,it will break an oxygen molecule into two parts and this will now combine with oxygen molecule available in the atmosphere to form OZONE( combination of three oxygen atoms). Ozone layer is the shield which helps to reduce the direct impact of the Sun radiation from aversely affecting the Earth.