Plants and animals require water that are moderately pure91. Plants and animals require water that are moderately pure, and they cannot survive if A B с D water is loaded with toxic chemicals. 92. Water pollution can kill a large number of fish, birds, but other animals; in some cases C A B it may kill all members of a species in an affected area. Ꭰ 93. It said that mathematics is the base of all other sciences, and that arithmetic, the science A B C of number, is the base of mathematics. D 94. One step beyond automated machines is the industrial robot, the heart and brain of that B A C is the microcomputer. D 95. Experts in psychology believe that for many people money is an importance symbol of A B C strength and influence. D 96. In recent years, there have been great increases in a number of engineers and scientists A B employed in American industries. C D 97. Although Yuri Gagarin first space flight lasted only 108 minutes, it gave encouragement A B C D to those who were interested in the future of manned space flight. 98. Electronic computers are wonderful proof of how clever people are at work out ways of A B C D helping themselves. 99. Physical fitness does not guarantee good health, but they provide a big step toward living A B C a long and healthy life. D 100. Nylon, a synthetic, make from a combination of water and a by-product of coal, was B C A first introduced in 1938. D |