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ęCһ俼(jng)ҪWYx{(dio)
F(xin)ڸW(wng)վx俼(jng)ͼкܶ@Щ(ni)҂Ă俼ЎǴҪWYxҪһEҪW(j)ԼČHrM{(dio){(dio)֮ǰһҪM֪Լˮƽ~RZwϵLyֻг˽ԼĆ}cᘌԵĽb俼(jng)ԼĂ俼|(zh)
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According to paragraph 4, what aspect of extinction episodes does the companion-star hypothesis supposedly clarify?
A. Their location
B. Their frequency
C. Their duration
D. Their severity
companion star hypothesisP(gun)I~λһThe possibility that mass extinctions may recur periodically has given rise to such hypotheses as that of a companion star with a long-period orbit deflecting other bodies from their normal orbits, making some of them fall to Earth as meteors and causing widespread devastation upon impact.fmass extinctionķͰl(f)֧companion star hypothesis@hypothesisf܉׃ΌһЩwƫx܉ɞEǵԭfҴΰl(f)܉extinctionlʣB}һҪԭĞ}ȡиx߷