Plants and animals require water that are moderately pure

91. 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