Which of the following most logically completes the

argument below?

When mercury-vapor streetlights are used in areas inhabited by insecteating bats, the bats feed almost exclusively around the lights, because the lights attract flying insects. ln Greenville, the mercury-vapor streetlights are about to be replaced with energysaving sodium streetlights, which do not attract insects. This change is likely to result in a drop in the population of insectcating bats in Greenville, since _______________.

Curator: lf our museum lends Venus to the Hart lnstitute for their show this spring, they will lend us their Rembrandt etchings for our print exhibition next fall. Having those etchings will increase attendance to the exhibition and hence increase revenue from our general admission fee.

Museum Administrator: But Venus is our biggest attraction. Moreover the Hart’s show will run for twice as long as our exhibition. So on balance the number of patrons may decrease.

The point of the administrator’s response to the curator is to question

Which of the following best completes the passage below?

At a recent conference on environmental threats to the North Sea, most participating countries favored unrform controls on the quality of effluents, whether or not specific environmental damage could be attributed to a particular source of effluent. What must, of course, be shown, in order to avoid excessively restrictive controls, is that ________________.

A certain species of desert lizard digs tunnels in which to lay its eggs. The eggs must incubate inside the tunnel for several weeks before hatching, and they fail to hatch if they are disturbed at any time during this incubation period, Yet these lizards guard their tunnels for only a few days after laying their eggs.

Which of the following, if true, most helps explain why there is no need for lizards to guard their tunnels for more than a few days?

ln setting environmental standards for industry and others to meet, it is inadvisable to require the best results that stateof-theart technology can achieve. Current technology is able to detect and eliminate even extremely minute amounts of contaminants, but at a cost that is exorbitant relative to the improvement achieved. So it would be reasonable instead to set standards by taking into account all of the current and future risks involved.

The argument given concerning the reasonable way to set standards presupposes that

A company plans to develop a prototype weeding machine that uses cutting blades with optical sensors and microprocessors that distinguish weeds from crop plants by differences in shade of color. The inventor of the machine claims that it will reduce labor costs by virtually eliminating the need for manual weeding.

Which of the following is a consideration in favor of the company’s implementing its plan to develop the prototype?

Aroca City currently funds its public schools through taxes on property. In place of this system, the city plans to introduce a sales tax of 3 percent on all retail sales in the city. Critics protest that 3 percent of current retail sales falls short of the amount raised for schools by property taxes. The critics are correct on this point. Nevertheless, implementing the plan will probably not reduce the money going to Aroca’s schools. Several large retailers have selected Aroca City as the site for huge new stores, and these are certain to draw large numbers of shoppers from neighboring municipalities, where sales are taxed at rates of 6 percent and more. ln consequence, retail sales in Aroca City are bound to increase substantially.

ln the argument given, the two portions in boldface play which of the following roles?