A growing world population and the discoveries of science may __11__ this pattern of distribution in the future. As men slowly learn to master diseases, control floods, prevent famines, and stop wars, fewer people die every year; and in __12__ the population of the world is __13__ increasing. In 1925 there were about 2,000 million people in the world; by the end of the century there may well be over 4,000 million.
When numbers rise the 14 mouths must be fed. New lands must be I bought under cultivation, or land already farmed made to __15__ larger crops. In some areas the accessible land is largely so intensively __16__ that it will be difficult to make it provide more food. In some areas the population is so dense that the land is parceled out in units too __17__ to allow for much improvement in farming methods. Were a larger part of this farming population drawn off into industrial occupations, the land might be farmed much more productively by modern methods.
There is now a race for science, technology, and industry to keep the __18__ of food rising faster than the number of people to be fed. New strains of crops are being developed which will thrive in __19 __climates; irrigation and dry-farming methods bring poor lands under the plough, dams hold back the waters of great rivers to __20__ water for the fields in all seasons and to provide electric power for new industries; industrial chemistry provides fertilizers to suit particular soils; aero planes spray crops to destroy insects and many plant diseases.
A. ensure
B. violently
C. alter
D. harmful
E. cultivated
F. unique
G. transplanted
H. yield
I. consequence
J. output
K. extra
L. steadily
M. tiny
N. unfavorable
O. produce
II. C 12. I 13. L 14. K 15. H 16. E 17. M 18. J 19. N 20. A