This is an old LSAT question.
A does not strengthen the conclusion.
-- by 会员 sdcar2010 (2011/5/31 11:00:57)
A is irrelevant to the argument.
Whether UV-B is the only type that can damage genes, it is still true that "Atmospheric ozone blocks UV-B, which can damage genes". A adds neither support nor oppostition to the argument.
D rules out another factor that may contribute to the decline of amphibian population and therefore strengthens the argument.
-- by 会员 kikisunflower (2011/5/31 10:50:13)