"Headhunters" are firms that, for a fee, undertake to recruit for their clients personnel

a phenomenon known as a red tide. Sea otters do not feed in areas where clams, their main source of food, have become contaminated with this toxin. According to a proposed explanation of the otters behavior, the otters sample the clams in a potential feeding area and can taste any toxin in them. Which of the following, if true, would most strongly indicate that the hypothesis described in the last sentence of the passage is not correct?

A．In some of the areas where red tides occur, neither clams nor sea otters are indigenous species.

B．The presence of sea otters in a given area has a significant effect on which other marine organisms are to be found in that area.

C．When seawater in an area unaffected by red tide is artificially dyed brownish red, sea otters do not feed on the clams in that area.

D．If the clams in a given area are contaminated with toxins, sea otters move to other areas in search of food.

E．Although very small amounts of the toxin produced during a red tide are not harmful, large doses can be fatal to animals the size of sea otters.

al injury—now have lower incomes and higher divorce rates, and score lower on psy chological profiles measuring general happiness, than medical personnel who served in less stressful settings during that war. This evidence demonstrates that exposure to heavy-combat situations produces serious adverse effects, even among those who suffered no physical harm. Which of the following, if true, most strengthens the conclusion drawn above?

A．The medical personnel who served in heavy combat had completed significantly less schooling prior to military service than had other medical personnel.

B．The medical personnel who served in heavy combat tended to be younger at the time of their entry into military service than were other medical personnel.

C．Parents of medical personnel who served in heavy combat show no significant difference in incomes, divorce rates, or general happiness from parents of other medical personnel.

D．Income levels, divorce rates, and levels of general happiness are the same for the medical personnel who served in heavy combat as they are for construction workers.

E．Medical personnel who served in heavy combat in an earlier war show no significant difference in incomes, divorce rates, or general happiness from other medical personnel who served in that war.

the fact that different local populations of bowerbirds of the same species build bowers that exhibit different building and decorative styles, researchers have concluded that the bowerbirds building styles are a culturally acquired, rather than a genetically transmitted, trait. Which of the following, if true, would most strengthen the conclusion drawn by the researchers?

A．There are more common characteristics than there are differences among the bower-building styles of the local bowerbird population that has been studied most extensively.

B．Young male bowerbirds are inept at bower-building and apparently spend years watching their elders before becoming accomplished in the local bower style.

C．The bowers of one species of bowerbird lack the towers and ornamentation characteristic of the bowers of most other species of bowerbird.

D．Bowerbirds are found only in New Guinea and Australia, where local populations of the birds apparently seldom have contact with one another.

E．It is well known that the song dialects of some songbirds are learned rather than transmitted genetically.

and only those private planes equipped with radar, most of the private-plane traffic would be forced to use outlying airfields. Such a reduction in the amount of private-plane traffic would reduce the risk of midair collision around the centrally located airports. Which of the following, if true, would most strengthen the conclusion drawn in the second sentence?

A．Commercial airliners are already required by law to be equipped with extremely sophisticated radar systems.

B．Centrally located airports are experiencing overcrowded airspace primarily because of sharp increases in commercial-airline traffic.

C．Many pilots of private planes would rather buy radar equipment than be excluded from centrally located airports.

D．The number of midair collisions that occur near centrally located airports has decreased in recent years.

E．Private planes not equipped with radar systems cause a disproportionately large number of midair collisions around centrally located airports.

esponding surge in claims against companies underwriting satellite insurance. As a result, insurance premiums shot up, making satellites more expensive to launch and operate. This, in turn, has added to the pressure to squeeze more performance out of currently operating satellites. Which of the following, if true, taken together with the information above, best supports the conclusion that the cost of television satellites will continue to increase?

A．Since the risk to insurers of satellites is spread over relatively few units, insurance premiums are necessarily very high.

B．When satellites reach orbit and then fail, the causes of failure are generally impossible to pinpoint with confidence.

C．The greater the performance demands placed on satellites, the more frequently those satellites break down.

D．Most satellites are produced in such small numbers that no economies of scale can be realized.

E．Since many satellites are built by unwieldy international consortia, inefficiencies are inevitable.

specially one without a signature or with a questionably authentic signature, is indubitably the work of this or that particular artist. This fact gives the traditional attribution of a disputed painting special weight, since that attribution carries the presumption of historical continuity. Consequently, an art historian arguing for a deattribution will generally convince other art historians only if he or she can persuasively argue for a specific reattribution. Which one of the following, if true, most strongly supports the position that the traditional attribution of a disputed painting should not have special weight?

A．Art dealers have always been led by economic self-interest to attribute any unsigned paintings of merit to recognized masters rather than to obscure artists.

B．When a painting is originally created, there are invariably at least some eyewitnesses who see the artist at work, and thus questions of correct attribution cannot arise at that time.

C．There are not always clearly discernible differences between the occasional inferior work produced by a master and the very best work produced by a lesser talent.

D．Attribution can shape perception inasmuch as certain features that would count as marks of greatness in a master"s work would be counted as signs of inferior artistry if a work were attributed to a minor artist.

E．Even though some masters had specialists assist them with certain detail work, such as depicting lace, the resulting works are properly attributed to the masters alone.

ing the acts standards for automobile emissions was neither economically feasible nor environmentally necessary. However, the catalytic converter, invented in 1967, enable automakers to meet the 1970 standards efficiently. Currently, automakers are lobbying against the governments attempt to pass legislation that would tighten restrictions on automobile emissions. The automakers contend that these new restrictions would be overly expensive and unnecessary to efforts to curb air pollution. Clearly, the automobile industrys position should not be heeded. Which one of the following, if true, lends the most support to the automakers current position?

A．The more stringent the legislation restricting emissions becomes, the more difficult it becomes for automakers to provide the required technology economically.

B．Emissions-restriction technology can often be engineered so as to avoid reducing the efficiency with which an automobile uses fuel.

C．Not every new piece of legislation restricting emissions requires new automotive technology in order for automakers to comply with it.

D．The more automobiles there are on the road, the more stringent emission restrictions must be to prevent increased overall air pollution.

E．Unless forced to do so by the government, automakers rarely make changes in automotive technology that is not related to profitability.

ll bits of plastic bound together by a degradable bonding agent such as cornstarch. Since only the bonding agent degrades, leaving the small bits of plastic, no less plastic refuse per container is produced when such containers are discarded than when comparable nonbiodegradable containers are discarded. Which of the following, if true, most strengthens the argument above?

A．Both partially biodegradable and nonbiodegradable plastic beverage containers can be crushed completely flat by refuse compactors.

B．The partially biodegradable plastic beverage containers are made with more plastic than comparable nonbiodegradable ones in order to compensate for the weakening effect of the bounding agents.

C．Many consumers are ecology-minded and prefer to buy a product sold in the partially biodegradable plastic beverage containers rather than in nonbiodegradable containers, even if the price is higher.

D．The manufacturing process for the partially biodegradable plastic beverage containers results in less plastic waste than the manufacturing process for nonbiodegradable plastic beverage containers.

E．Technologica" problems with recycling currently prevent the reuse as food or beverage containers of the plastic from either type of plastic beverage container.

aintains feeding behavior. Only when a caterpillar has grown to the right size for pupation to take place does a special enzyme halt the production of juvenile hormone. This enzyme can be synthesized and will, on being ingested by immature caterpillars, kill them by stopping them from feeding. Which of the following, if true, most strongly supports the view that it would not be advisable to try to eradicate agricultural pests that go through a caterpillar stage by spraying croplands with the enzyme mentioned above?

A．Most species of caterpillar are subject to some natural predation.

B．Many agricultural pests do not go through a caterpillar stage.

C．Many agriculturally beneficial insects go through a caterpillar stage.

D．Since caterpillars of different species emerge at different times, several sprayings would be necessary.

E．Although the enzyme has been synthesized in the laboratory, no large-scale production facilities exist as yet.

ribed as one of

A．respectful regard.

B．qualified approbation.

C．implied skepticism.

D．pointed criticism.

E．fervent advocacy.