大学英语四六级考试阅读提高的练习（30）

　　11 the distribution of life on Earth. Climatic boundaries establish the limits within which organisms can survive. Plants, even more than animals, must be 12 adapted to climate in order to survive. They cannot move about or take shelter but must be equipped to 13 whatever weather conditions are likely to occur. In the harsh conditions of the far north of the earth, for example, low growing mosses, lichens, and a few flowering plants all hold to the ground for shelter from icy winds.

　　Animals, despite their 14 to move about and find shelter, are just as much influenced by climate as plants are. Creatures such as the camel and the penguin are so highly specialized that they have an 15 limited distribution. Others, such as bears, are flexible enough to adapt to a 16 range of climates.. Ocean-dwelling organisms are just as sensitive to climatic changesin this case temperature and salinityas land animals. Reef corals can survive only in clear warm seawater. Certain foraminaters are so sensitive to changes in their 17 that their presence can be taken as an 18 of sea temperature. Human beings are among the 19 specialized of all animals and can live almost anywhere. Their clothes and their homes 20 as a sort of miniature climate that can be taken with them everywhere.

　　A. least B. determines c. ability D. urgently

　　E. broad F. behave G. worst H. index

　　I. endure J. extremely K. entertain L. well

　　M. neighborhood N. act O. environment

　　II. B 12. L 13. I 14. C 15. J 16. E 17. O 18. H