Large animals that inhabit the desert have evolved a number of adaptations for reducing the effects of extreme heat.【C1】______ad

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问题     Large animals that inhabit the desert have evolved a number of adaptations for reducing the effects of extreme heat.【C1】______adaptation is to be light in color, and to【C2】______rather than absorb the sun’s rays. Desert mammals also depart from the normal mammalian practice of maintaining a 【C3】______body temperature.【C4】______trying to keep down the body temperature deep inside the body, which would involve the expenditure of water and energy, desert mammals allow their temperatures to rise to what would normally be fever【C5】______, and temperatures as high as 46 degrees Celsius have been measured in gazelles(瞪羚羊).
    Another strategy of large desert animals is to tolerate the loss of body water to a point【C6】______would be fatal for non-adapted animals. The camel can lose up to 30 percent of its body weight as water without harm to itself,【C7】______human beings die after losing only 12 to 13 percent of their body weight. An equally important adaptation is the ability to【C8】______this water loss at one drink. Desert animals can drink prodigious’ volumes in a short time, and camels have been known to 【C9】______over 100 liters in a few minutes. A very dehydrated person,【C10】______, cannot drink enough water to rehydrate at one【C11】______, because the human stomach is not sufficiently big and because a too rapid【C12】______of the body fluids causes death from water intoxication. The 【C13】______of water loss is of obvious advantage in the desert, as animals do not have to remain 【C14】______a water hole but can obtain food from grazing sparse and far-flung pastures. Desert-adapted mammals have the further ability to feed normally when extremely dehydrated; it is a common experience in people that appetite is lost even【C15】______conditions of moderate thirst.
【C7】

选项 A、however
B、whereas
C、on the contrary
D、when

答案B

解析 逻辑关系。本句明显是骆驼与人类之间的对比,此处需要一个转折连词。whereas符合句意。however也表示转折,但它后面需用逗号隔开;on the contrary后面也需用逗号隔开,用在“前面否定了他人所言,相反地,后面才是事实”的结构里,它前后半句的主语是指同一对象。故答案为B。
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