7. The price of maple syrup has jumped from 22 dollars three years ago to 40 dollars a gallon today. It can be concluded that maple-syrup harvesters have been artificially inflating prices and that governmental price regulations are necessary to control rising prices.Which of the following， if ture， casts the most doubt on the conclusion drawn above?
(A) The government already requires maple-syrup harvesters to submit their facilities to licensing by the health department. (B) Insect infestation and drought have stunted the growth of syrupproducing maple trees and caused less-abundant syrup harvests.
(C) Maple syrup is produced in rural areas that suffer from high unemployment.
(D) Technological improvements in maple-syrup harvesting have reduced production costs.
(E) Maple-syrup prices have risen many times in the past， though never before at the rate recently observed.
8. Artificial seaweed made of plastic has been placed on a section of coast in order to reverse beach erosion. The inventor of the seaweed has concluded that the recent buildup of sand on that section of coast proves that the artificial seaweed reverse beach erosion.Which of the following， if true， would most seriously weaken the inventor’s conclusion?
(A) The amount of recent sand buildup on that section of coast was less than had been predicted on the basis of the results obtained in controlled experiments.
(B) Because artificial seaweed would be buried eventually by additional sand deposits on the coast， more artificial seaweed would need to be put in place every four years.
(C) Artificial seaweed of another material which had been previously developed by the inventor failed to add sand to coastline in past trials.
(D) The amount of recent sand buildup on that section of coast is the same as the amount of recent sand buildup on otherwise very similar section of coast without artificial seaweed.
(E) The amount of recent sand buildup on that section of coast， although considerable， is not yet enough to replace the amount lost during storms on that section of coast in the last twenty years.
9. The presence of microorganisms that produce a toxin causes seawater to turn brownish red， 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 areas 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 areas 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.
10. Since 1945 there have been numerous international confrontations as tense as those that precipitated the Second World War， and yet no large-scale conflict has resulted. To explain this， some argue that fear of enomous destruction such as the Second World War produced has had a dramatic deterrent effect.
Which of the following .if true， most seriously weakens the deterrent theory mentioned above?
(A) After the First World War， the fear of great future destruction was as intense as it was after the Second World War.
(B) Psychologists have detemined that fear of retaliation tends to temper aggressiveness among human beings.
(C) The Second World War was far less destractive than most people gen- erally believe.
(D) Fear of repeating the levels of destructions that the Second World War produced is as pervasive today as it was forty years age.
(E)Many of the international confrontations that have occurred since 1945 have involved countries that participated in the Second World War.
11. A conservation group in the United States is trying to change the long-standing image of bats as frightening creatures. The group contends that bats are feared and persecuted solely because they are shy animals that are active only at night.
Which of the following， if true， would cast the most serious doubt on the accuracy of the group’s contention?
(A) Bats are steadily losing natural roosting places such as caves and hollow rees and are thus turning to more developed areas for roosting.
(B) Bats are the chief consumers of nocturnal insects and thus can help make their hunting territory more pleasant for humans.
(C) Bats are regarded as frightening creatures not only in the United States but also in Europe， Africa， and South America.
(D) Raccoons and owls are shy and active only at night; yet they are not generally feared and persecuted.
(E) People know more about the behavior of other greatly feared animal species， such as lions， alligators， and snakes， than they do about the behavior of bats.
12.The population of peregrine falcons declined rapidly during the 1950’s and 1960’s and reached an all-time low in the early 1970’s. The decline was attributed by scientists to the widespread use of the pesticide DDT in rural areas.
Which of the following ， if true， gives the strongest support to the scientists claim?
(A) DDT was not generally in use in areas devoted to heavy industry.
(B) In the time since the use of DDT was banned in 1972， the population of peregrine falcons has been steadily increasing.
(C) Peregrine falcons， like other birds of prey， abandon eggs that have fallen out of the nest， even if the eggs remain intact.
(D) Starlings， house sparrows， and blue jay-birds the peregrine falcon prey on-were not adversely affected by DDT in their habitats.
(E) Other birds of prey， such as the osprey， the bald eagle， and the brown pelican， are found in the same areas as is the peregrine falcon.
