1.(Z)Nitrogen dioxide is a pollutant emitted by automobiles. Catalytic converters, devices designed to reduce nitrogen dioxide emissions, have been required in all new cars in Donia since 1993, and as a result, nitrogen dioxide emissions have been significantly reduced throughout most of the country. Yet although the proportion of new cars in Donia’s capital city has always been comparatively high, nitrogen dioxide emissions there have showed only an insignificant decline since 1993.
Which of the following, if true, most helps to explain the insignificant decline in nitrogen dioxide emissions in Donia’s capital city?
A. More of the cars in Donia’s capital city were made before 1993 than after 1993.
B. The number of new cars sold per year in Donia has declined slightly since 1993.
C. Pollutants other than nitrogen dioxide that are emitted by automobiles have also been significantly reduced in Donia since 1993.
D. Many Donians who own cars made before 1993 have had catalytic converters installed in their cars.
E. Most car trips in Donia’s capital city are too short for the catalytic converter to reach its effective working temperature.
2.(Z)Escalating worldwide demand for corn has led to a sharp increase in the market price of corn, and corn prices are likely to remain high. Corn is extensive used as feed for livestock, and because profit margins are tight in the livestock business, many farmers are expected to leave the business. With fewer suppliers, meat prices will surely rise. Nonetheless, observers expect an immediate short-term decrease in meat prices.
Which of the following, if true, most helps to justify the observers’ expectation?
A. The increase in corn prices is due more to a decline in the supply of corn than to a growth in demand for it.
B. Generally, farmers who are squeezed out of the livestock business send their livestock to market much earlier than they otherwise would.
C. Some people who ate meat regularly in the past are converting to diets that include little or no meat.
D. As meat prices rise, the number of livestock producers is likely to rise again.
E. Livestock producers who stay in the business will start using feed other than corn more extensively than they did in the past.
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