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  3. Small dogs generally live longer than big dogs so that small Yorkshire terri

Small dogs generally live longer than big dogs so that small Yorkshire terri

游客2024-05-08  38
问题     Small dogs generally live longer than big dogs so that small Yorkshire terrier (猎狐狗) next door could be around for a long time. But body size isn’t the only factor that【B1】______how long dogs survive. Personality influences life span, too, according to a new study that might help explain how animal【B2】______evolve.
    Study on animals from ants to apes has found that different【B3】______have different personalities. Some are timid, others【B4】______. Biologists have proposed that temperaments (性情) evolved along with life history.【B5】______, violent animals use a lot of energy fast in【B6】______short lives, the thinking goes, whereas calmer animals last longer, saving themselves to【B7】______ later in life. But it’s hard to run evolutionary【B8】______on these personalities in anything longer lived than a fruit fly. So evolutionary biologist Vincent from Canada came up with an idea about dogs. "All these breed differences reflect an experiment on artificial selection," says Vincent.【B9】______—the ability to chase foxes into holes, or herd sheep, or sit attractively on a sofa.
    But evolutionary physiologist Joseph Williams of Ohio State University in Columbus isn’t convinced that 【B10】______. "For me, it still remains to be seen. Dogs are contrary to what you would expect in nature in terms of longevity," he says.【B11】______. On the other hand, a Chihuahua will generally outlast a Saint Bernard. [br] 【B9】
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答案 The huge diversity of dogs resulted not from natural selection, but from generations of humans selecting animals with traits
解析 huge, diversity, resulted, natural selection, humans, selecting, traits
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