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B. They occur in greater quantities than other pollutants.
C. They are less harmful to living beings than other pollutants.
D. They have existed since the Earth developed.
Question 25. According
to the passage, human-generated air pollution in localized regions _____.
A. can be dwarfed by nature's
output of pollutants
B. can overwhelm the natural system that removes pollutants
C. will damage areas outside
of the localized regions
D. will react harmfully with natural pollutants
Question 26. The word ―localized‖ in the third paragraph is closest in meaning to _____.
A. specified
B. circled
C. surrounded
D. encircled
Question 27. According to the passage, the numerical value of the concentration level of a
substance is only useful if _____.
A. the other substances
in the area are known
B. it is in a localized area
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