Some soil scientists have asserted that decaying matter on the forest floor is a far greater source of the acidity in mountain lakes than is the acid rain that falls on these lakes. Therefore, they contend, reducing acid rain will not significantly reduce the acidity levels of mountain lakes. Which of the following statements, if true, most seriously weakens the argument above？
A. It is natural for mountain lakes to have acidity levels higher than those of other lakes.
B. The harmful effects of increased acidity levels in lakes have been greatly underestimated.
C. Acid rain is found in urban and heavily industrialized regions of the country.
D. There is much disagreement among soil scientists about the causes of acid rain.
E. While plant life remains, acid rain significantly increases the amount of decaying organic matter in natural environments.
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Defendants who can afford expensive private defense lawyers have a lower conviction rate than those who rely on court-appointed public defenders. This explains why criminals who commit lucrative crimes like embezzlement or insider trading are more successful at avoiding conviction than are street criminals. The explanation offered above would be more persuasive if which one of the following were true？
A. Many street crimes, such as drug dealing, are extremely lucrative and those committing them can afford expensive private lawyers.
B. Most prosecutors are not competent to handle cases involving highly technical financial evidence and have more success in prosecuting cases of robbery or simple assault.
C. The number of criminals convicted of street crimes is far greater than the number of criminals convicted of embezzlement or insider trading.
D. The percentage of defendants who actually committed the crimes of which they are accused is no greater for publicly defended than for privately defended defendants.
E. Juries, out of sympathy for the victims of crimes, are much more likely to convict defendants accused of violent crimes than they are to convict defendants accused of "victimless" crimes or crimes against property.
A common misconception is that university hospitals are better than community or private hospitals. In fact, university hospitals have a lower survival rate for patients than do other hospitals. From this it seems clear that the quality of care at university hospitals is lower than that at other hospitals. Which of the following, if true, most forcefully undermines the argument of the passage above？
A. Many doctors divide their working hours between a university and a community or private hospital.
B. Doctors at university hospitals often earn less than doctors at private hospitals.
C. University and community hospitals often cannot afford the elaborate facilities of private hospitals.
D. The emphasis at many university hospitals is on pure research rather than on the treatment and care of patients.
E. The patients who seek help at university hospitals are usually more seriously ill than those at private or community hospitals.
The pharmaceutical industry argues that because new drugs will not be developed unless heavy development costs can be recouped in later sales, the current 20 years of protection provided by patents should be extended in the case of newly developed drugs. However, in other industries new-product development continues despite high development costs, a fact that indicates that the extension is unnecessary. Which of the following, if true, most strongly supports the pharmaceutical industry s argument against the challenge made above？
A. No industries other than the pharmaceutical industry have asked for an extension of the 20-year limit on patent protection.
B. Clinical trials of new drugs, which occur after the patent is granted and before the new drug can be marketed, often now take as long as 10 years to complete.
C. There are several industries in which the ratio of research and development costs to revenues is higher than it is in the pharmaceutical industry.
D. An existing patent for a drug does not legally prevent pharmaceutical companies from bringing to market alternative drugs, provided they are sufficiently dissimilar to the patented drug.
E. Much recent industrial innovation has occurred in products—for example, in the computer and electronics industries—for which patent protection is often very ineffective.
Some who favor putting governmental enterprises into private hands suggest that conservation objectives would in general be better served if private environmental groups were put in charge of operating and financing the national park system, which is now run by the government. Which of the following, assuming that it is a realistic possibility, argues most strongly against the suggestion above？
A. Those seeking to abolish all restrictions on exploiting the natural resources of the parks might join the private environmental groups as members and eventually take over their leadership.
B. Private environmental groups might not always agree on the best ways to achieve conservation objectives.
C. If they wished to extend the park system, the private environmental groups might have to seek contributions from major donors and the general public.
D. There might be competition among private environmental groups for control of certain park areas.
E. Some endangered species, such as the California condor, might die out despite the best efforts of the private environmental groups, even if those groups are not hampered by insufficient resources.
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