Climate, more than any other single factor, __1__the distribution of life on Earth. Climatic boundaries establish the limits within which organisms can survive. Plants, even more than animals, must be__2__ adapted to climate in order to survive. They cannot move about or take shelter but must be equipped to __3__ 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 __4__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 __5__ limited distribution. Others, such as bears, are flexible enough to adapt to a __6__range of climates.. Ocean-dwelling organisms are just as sensitive to climatic changes—in this case temperature and salinity—as land animals. Reef corals can survive only in clear warm seawater. Certain foraminaters are so sensitive to changes in their__7 __that their presence can be taken as an __8__ of sea temperature. Human beings are among the __9 __ specialized of all animals and can live almost anywhere. Their clothes and their homes __10__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

Key:I. B 2. L 3. I 4. C 5. J 6. E 7. O 8. H 9.A10.F