9. Measurements of the motion of the planet Uranus¹ seem to show Uranus being tugged² by a force pulling it away from the Sun and the inner planets. Neptune³ and Pluto⁴, the two known planets whose orbits are farther from the Sun than is the orbit of Uranus, do not have enough mass to exert the force that the measurements indicate. Therefore, in addition to the known planets, there must be at least one planet in our solar system that we have yet to discover.

Which one of the following, if true, most seriously weakens the argument?

(A) Pluto was not discovered until 1930
(B) There is a belt of comets beyond the orbit of Pluto with powerful gravitatinal pull.
(C) Neither Neptune nor Pluto is as massive as Uranus.
(D) The force the Sun exerts on Uranus is weaker than the force it exerts on the inner planets.
(E) Uranus' orbit is closer to Neptune's orbit than it is to Pluto's.

10. Audiences find a speaker more convincing if the speaker begins a speech by arguing briefly⁵ against his or her position before providing reasons for accepting it. The reason this technique is so effective is that it makes the speaker appear fair-minded and trustworthy. Therefore, candiadates for national political office who wish to be argumentative technique in their speeches.

Which one of the following, if true, most seriously limits the effectiveness of adopting the argument's recommendation?

(A) Political candidates typically have no control over which excerpts⁶ from their speeches will be reported by the news media.
(B) Many people do not find arguments made by politicians convincing, since the arguments are often one-sided or oversimplify the issues.
(C) People decide which political candidate to vote for more on the basis of their opinions of the candidate's character than on the exact positions of the candidate.
(D) People regard a political candidate more favorably if they think that the candidate respects an opponent's position even while disagreeing with it.
(E) Political candidates have to address audiences of many different sizes and at many different locations in the course of a political campaign.

11. Five thousand of the 50,000 books published in country Z in 1991 were novels. Exactly 25 of the films released in country Z in 1992 were based on those novels. Since 100 films were released in country Z in 1992, no more than one-quarter of them were based on books published in country Z in 1991.

Which one of the following, if assumed, allows the conclusion above to be properly drawn⁷?

(A) None of the scripts used in films released in 1992 were written by professional novelists.
(B) None of the films released in country Z in 1992 were based on books other than novels.
(C) None of the books that were published in country Z in 1992 were based on plots of films released in 1991.
(D) Some of the films released in country Z in 1992 for the first time many years earlier.
(E) Some of the films released in 1991 in country Z were based on novels that were published in 1991

12. On their way from their nest to a food source, ants of most species leave a trail of chemicals called pheromones. The ants use the scent⁸ of the pheromones to guide themselves between the food and their nest. All pheromones evaporate without a trace almost immediately when temperatures rise above 45 degrees Clesius (113 degrees Fahrenheit), as is typical during afternoons in places such as the Sahara Desert.

The statements above, if true, most strongly support which one of the following?

(A) Most ants forage⁹ for food either only in the morning or only during the night.
(B) Most ants that do not use pheromones to mark the paths they take between their nest and food live in the Sahara Desert.
(C) If any ants live in the Sahara Desert and forage for food at no time but in afternno, those ants generally do not use pheromones to guide themselves between food and their nest.
(D) If any ants do not use pheromones to navigate¹⁰ between food and their nest, those ants use a different substance that does not evaporate in temperatures above 45 degrees Celsius¹¹.
(E) If any Saharan ants forage for food in the afternoon, those ants forage for food less efficiently¹² when temperatures are above 45 degrees Celsius than they do when temperatures are lower.

13. Some people think that in every barrel of politicians there are only a few rotten ones. But if deceit is a quality of rottenness, I believe all effective politicians are rotten. They must be deceitful in order to do the job properly. Someone who is scrupulously¹³ honest about obeying the rules of society will never be an effective politician.

Assuming that the author's statements are accurate, which one of the following statements CANNOT be true?

(A) Some people think all politicians are rotten
(B) Some politicians are scrupulously honest.
(C) Some poeple define a politician's job as obeying the rules of society
(D) Some deceitful politicians are ineffective.
(E) Some scrupulously honest politicians are effective.

14. The Biocarb Company wants to build a sterilization¹⁴ plant to treat contaminated medical waste in a city neighborhood where residents and environmental activists¹⁵ fear that such a facility will pollute the area. Biocarb's president argues that the operation of the plant cannot cause pollution because the waste would be sterile¹⁶ after processing by the plant. He claims that after exposure for an hour to superheated steam in the autoclave, such refuse would be far cleaner than food prepared in the cleanest kitchen.

The president's argument depends on which one of the following assumptions?

(A) Environmental activists believe that waste treated with steam will not pollute.
(B) Handling of the waste before treatment in the proposed facility will not pose a threat of pollution to the area.
(C) Fear of pollution is the only argument against construction of an autoclave facility for medical waste.
(D) No others besides environmental activists are concerned about pollution hazards that can result from processing medical waste.
(E) Treatment by superheated steam represents the surest method of sterilization.

15. Grow-Again ointment¹⁷ is a proven treatment for reversing male hereditary¹⁸ baldness. Five drops daily is the recommended does and exceeding this quantity does not increase the product's effectiveness. Therefoe, offering a manufacturer's rebate¹⁹ on the purchase price of Grow-Again will not increase sales and consequently would be unprofitable for the manufacturer.

Which one of the following, if true, would most strengthen the argument?

(A) When using an ointment, people tend to believe that applying it in greater quantities can make it more effective.
(B) Grow-Again is more effective on some of the men who use it than it is on others.
(C) The rebate, if offered, would not attract purchasers who otherwise might not use Grow-Again.
(D) Baldness in men can be caused by a variety of factors, only one of which is heredity.
(E) Grow-Again is a product whose per-unit manufacturing cost does not fall significantly when the product is produced in lareg quantities.