一道狒狒逻辑上的题目!

karma3001

Amphibian populations are declining in numbers worldwide.Not coincidentally, the earth's ozone layer has been continuously depleted throughout the last 50 years.Atmospheric ozone blocks UV-B,a type of ultraviolet radiation that is continuously produced by the sun,and which can damage genes.Because amphibians lack hair,hihde,or feathers to shield them,they are particularly vulnerable to UV-B radiation.In addition,their gelatious eggs lack the protection of leathery or hard shells.Thus,the primary cause of the declining amphibian population is the depletion of the ozne layer.
A Of the various types of radiation blocked by atmospheric ozone,UV-B is the onlh type that can damage genes.
排出法做的 可是除了排出法a怎么得出来的呢？ozone能否block别的射线根结论无关呀