Ask why most people are right-handed, and the answer might fall along the same lines as why fish school(鱼成群地游). Two neuroscienti

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问题     Ask why most people are right-handed, and the answer might fall along the same lines as why fish school(鱼成群地游). Two neuroscientists suggest that social pressures drive individuals to coordinate their behaviors so that everyone in the group gets an evolutionary edge.
    Approximately 85 percent of people prefer their right hand, which is controlled by the left hemisphere of the brain. One theorized benefit of locating a particular function in one hemisphere is that it frees the other to deal with different tasks. But that idea does not explain why population-wide trends for handedness exist in the first place.
    Moreover, evidence gleaned in recent years has overturned the long-held belief that human handedness is a unique by-product of brain specialization attributable to language. A suite of studies has revealed brain lateralization in species from fish to primates(灵长类). Last August, for instance, scientists discovered that in the wild, chimpanzees show hand preferences.
    The presence of lateralization throughout the animal kingdom suggests some benefit from it, contend neuroscientists Giorgio Vallortigara and Lesley Rogers. Also, last August, in the journal Behavioral and Brain Sciences, the two presented evidence to support their idea that social constraints force individuals toward asymmetry in the same direction. They noted, for example, that baby chickens attack more readily when a threat appears on their left.
Due to______, human handedness is not an exclusive phenomenon in animal world.

选项 A、brain lateralization found in species from fish to primates
B、different brain structures of species
C、brain specialization attributable to language
D、the asymmetrical brains of chimpanzees

答案A

解析 推理判断题。第三段说人们一直认为左右手习惯是人的特有特征,是人大脑中语言功能区进化的附属品,现在这个论断被推翻了。因为从鱼到灵长类动物(黑猩猩)的脑部都具有侧向性的发育特点。这与A项相符合,故选A。
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