Lake Springfield in the city of Springfield, Illinois, is a busy place where people swim and fish. The lake also supplies drinking water for Springfield residents and cooling water to a nearby coal-fired power plant.
Beautiful homes surround most of the lake. Over the past 15 years, the bacterium Leptospira, commonly found in agricultural animal waste, has been detected in this lake water, and some people have become sick. The contamination of the lake by Leptospira may best be prevented by A) better control of agricultural nonpoint source pollution of the lake.
B) doubling the amount of fluoride added to the city's public water supply.
C) restricting swimming in the lake to only weekends.
D) requiring the power company to find another source for its cooling water.
Question 2
National censuses reveal a drop in a nation's growth rate that occurs about 20 years before the number of persons added per year declined. This 20-year lag represents
A) new immigration policies that became law.
B) a drop in the number of people reaching reproductive age.
C) increased use of family planning techniques.
D) social pressures to reduce family size.
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