6. Simulations have shown that a gamma ray burst in our Milky Way could wipe out the stratospheric ozone layer for years, long enough to cause widespread ________
(A) experience
(B) extinction
(C) colosseum
(D) abstract
(E) extract
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統計: A(0), B(6), C(1), D(1), E(0) #3422547
統計: A(0), B(6), C(1), D(1), E(0) #3422547