新概念优美背诵短文50篇：细胞与温度.doc

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新概念优美背诵短文50篇：细胞与温度

★[无忧 考网]新概念英语频道为大家整理的新概念优美背诵短文50篇：细胞与温度，供大家参考。更多阅读请查看本站新概念英语频道新概念英语第三册lesson 3 An unknown goddess
Cells and Temperature
细胞与温度
Cells cannot remain alive outside certain limits of temperature, and much narrower limits mark the boundaries of effective functioning.
细胞只能在一定的温度范围内存活，而进一步保证它们有效工作的温度范围就更小了。
Enzyme systems of mammals and birds are most efficient only within a narrow range around 37℃; a departure of a few degrees from this value seriously impairs their functioning. Even though cells can survive wider fluctuations, the integrated actions of bodily systems are impaired. Other animals have a wider tolerance for changes of bodily temperature.
哺乳动物和鸟类的酶系统只能在37℃左右的很小范围内才能有效工作。与此相差仅几度的温度都会大大削弱它们的工作效率。尽管温度变化更大时细胞仍能存活，但机体系统的整体运行能力却被削弱了。其它动物对体温的变化有更强的适应性。
For centuries it has been recognized that mammals and birds differ from other animals in the way they regulate body temperature. Ways of characterizing the difference have become more accurate and meaningful over time, but popular terminology still reflects the old division into "warm blooded" and "cold blooded" species; warmblooded included mammals and birds whereas all other creatures were considered coldblooded. As more species were studied, it became evident that this classification was inadequate. A fence lizard or a desert iguanaeach coldbloodedusually has a body temper