Economist: Tropicorp, which constantly seeks profitable investment opportunities, has been buying and clearing sections of tropical forest for cattle ranching, although pastures newly created there become useless for grazing after just a few years. The company has not gone into rubber tapping, even though greater profits can be made from rubber tapping, which leaves the forest intact. Thus, some environmentalists argue that Tropicorp’s actions do not serve even its own economic interest. However, the initial investment required for a successful rubber-tapping operation is larger than that needed for a cattle ranch; there is a shortage of workers employable in rubber-tapping operations;and taxes are higher on profits from rubber tapping than on profits from cattle ranching. 
Consequently, the environmentalists’ conclusion is probably wrong.
In the economist’s argument, the two boldface portions play which of the following roles?

Film Director: It is true that certain characters and plot twists in my newly released film The Big Heist are similar to characters and plot twists in Thieves, a movie that came out last year.Pointing to these similarities, the film studio that produced Thieves is now accusing me of taking ideas from that film. The accusation is clearly without merit. All production work on The Big Heist was actually completed months before Thieves was released.
Which of the following, if true, provides the strongest support for the director’s position?

A study compared a sample of Swedish people older than 75 who needed in-home assistance with a similar sample of Israeli people. The people in the two samples received both informal assistance,provided by family and friends, and formal assistance, professionally provided.Although Sweden and Israel have equally well-funded and comprehensive systems for providing formal assistance, the study found that the people in the Swedish sample received more formal assistance, on average, than those in the Israeli sample.
Which of the following, if true, does most to explain the difference that the study found?

Farmer: Worldwide, just three grain crops—rice, wheat, and corn—account for most human caloric intake. To maintain this level of caloric intake and also keep pace with global population growth,yields per acre from each of these crops will have to increase at least 1.5 percent every year, given that the supply of cultivated land is diminishing.Therefore, the government should increase funding for research into new ways to improve yields.
Which of the following is an assumption on which the farmer’s argument depends?

Enterprise Bank currently requires Customers with checking accounts to maintain a minimum balance or pay a monthly fee. Enterprise plans to offer accounts with no monthly fee and no minimum-balance requirement; to cover their projected administrative costs of $3 per account per month they plan to charge $30 for overdrawing an account. Since each month on average slightly more than 10 percent of Enterprise's customers overdraw their accounts, bank officials predict the new accounts will generate a profit.
Which of the following, if true, most strongly supports the bank officials’ prediction?

More and more law firms specializing incorporate taxes are paid on a contingency-fee basis. Under this arrangement, if a case is won, the firm usually receives more than it would have received if it had been paid on the alternate hourly rate basis. If the case is lost, the firm receives nothing. Most firms are likely to make more under the contingency-fee arrangement.
Which of the following, if true, would most strengthen the prediction above?

Which of the following most logically completes the passage?
Leptin, a protein occurring naturally in the blood, appears to regulate how much fat the body carries by speeding up the metabolism and decreasing the appetite when the body has too much fat. Mice that do not naturally produce leptin have more fat than other mice, but lose fat rapidly when they are given leptin injections. Unfortunately, however,leptin cannot be used as a dietary supplement to control fat, since __________.

Plant scientists have used genetic engineering on seeds to produce crop plants that are highly resistant to insect damage. Unfortunately, the seeds themselves are quite expensive, and the plants require more fertilizer and water to grow well than normal ones. Accordingly, for most farmers the savings on pesticides would not compensate for the higher seed costs and the cost of additional fertilizer. However, since consumer demand for grains,fruits, and vegetables grown without the use of pesticides continues to rise,the use of genetically engineered seeds of this kind is likely to become widespread.
In the argument given, the two portions in boldface play which of the following roles?

The United Parcel Service plans to convert its more than 2,000 gasoline-powered trucks in the Los Angeles area to run on cleaner-burning natural gas.

Through experimenting designed to provide information that will ultimately prove useful in the treatment of hereditary diseases, mice have received bone marrow transplants that give them a new gene.