21. One method of dating the emergence of species is to compare the genetic material of related species. Scientists theorize that the more genetically similar two species are to each other, the more recently they diverged from a common ancestor. After comparing genetic material from giant pandas, red pandas, raccoons, coatis, and all seven bear species, scientists concluded that bears and raccoons diverged 30 to 50 million years ago. They further concluded that red pandas separated from the ancestor of today’s raccoons and coatis a few million years later, some 10 million years before giant pandas diverged from the other bears.
Which one of the following can be properly inferred from the passage?
(A) Giant pandas and red pandas are more closely related than scientists originally thought they were.
(B) Scientists now count the giant panda as the eighth species of bear.
(C) It is possible to determine, within a margin of just a few years, the timing of divergence of various species.
(D) Scientists have found that giant pandas are more similar genetically to bears than to raccoons.（D）
(E) There is substantial consensus among scientists that giant pandas and red pandas are equally related to raccoons.
研究不明白了，大家帮忙啊
提干
理论：One method of dating the emergence of species is to compare the genetic material of related species. Scientists theorize that the more genetically similar two species are to each other, the more recently they diverged from a common ancestor
两个物种之间基因越相似，他们从同一物种分家的时间里现在越近
bears and raccoons diverged 30 to 50 million years ago.
b和R，30 to 50 million 年前分家.
red pandas separated from the ancestor of today’s raccoons and coatis a few million years later
red pandas 在b和R分家a few million 后分家
some 10 million years before giant pandas diverged from the other bears.
giant pandas 在red pandas 分家some 10 million years 后分家
答案
giant pandas are more similar genetically to bears than to raccoons
与R相比，giant pandas 与其他熊的基因更相似
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