ACT Practice Test READING Passage XIII HUMANITIES: The following passage is excerpted from A Short History of Western Civilization by John Harrison, Richard Sullivan, and Dennis Sherman (©1990 by McGraw-Hill Reprinted by permission.) Enlightenment ideas were put forth by a variety of intellectuals who in France came to be known as the philosophes Philosophes is French for philosophers, and in a sense these thinkers were rightly considered philosophers, for the questions they dealt with were philosophical: How we discover truth? How should life be lived? What is the nature of God? But on the whole the term has a meaning different from the usual meaning of “philosopher.” The philosophes were intellectuals, often not formally trained or associated with a university They were usually more literary than scientific They generally extended, applied, popularized, or propagandized ideas of others rather than originating those ideas themselves The philosophes were more likely to write plays, satires, pamphlets or simply participate in verbal exchanges at select gatherings than to write formal philosophical books It was the philosophes who developed the philosophy of the Enlightenment and spread it to much of the educated elite in Western Europe (and the American colonies) Although the sources for their philosophy can be traced to the Scientific Revolution in general, the philosophes were most influenced by their understanding of Newton, Locke, and English institutions The philosophes saw Newton as the [5] [10] [15] [20] [25] [30] great synthesizer of the Scientific Revolution who rightly described the universe as ordered, mechanical, material, and only originally set in motion by God, who since then has remained relatively inactive Newton’s synthesis showed to the philosophes that reason and nature were compatible: Nature functioned logically and discernibly, and what was natural was also reasonable Newton exemplified the value of reasoning based on concrete experience The philosophes felt that his empirical methodology was the correct path to discovering truth John Locke (1632-1704) agreed with Newton but went further This English thinker would not exempt even the mind from the mechanical laws of the material universe In his Essay Concerning Human Understanding (1691), Locke pictured the human brain at birth as a blank sheet of paper on which nothing would ever be written except sense perception and reason What human beings become depends on their experiences—on the information received through the senses Schools and social institutions could therefore play a great role in molding the individual from childhood to adulthood Human beings were thus by nature far more malleable than had been assumed This empirical psychology of Locke rejected the notion that human beings were born with innate ideas or that revelation was a reliable source of truth Locke also enunciated liberal and reformist political ideas in his Second Treatise of Civil Government (1690), which influenced the philosophes On the whole, Locke’s empiricism, psychology and politics were appealing to the philosophes England, not coincidentally the country of Newton and Locke, became the admired model for many of the philosophes They tended to idealize it, but [35] [40] [45] [50] [55] [60] [65] [70] [75] England did seem to allow greater individual freedom, tolerate religious differences, and evidence greater political reform than other countries, especially France England seemed to have gone furthest in freeing itself from traditional institutions and accepting the new science of the seventeenth century Moreover, England’s approach seemed to work, for England was experiencing relative political stability and prosperity The philosophes wanted to see in their own countries much of what England already seemed to have Many philosophes reflected the influence of Newton, Locke, and English institutions, but perhaps the most representative in his views was Voltaire (1778) Of all leading figures of the Enlightenment, he was the most influential Voltaire, the son of a Paris lawyer, became the idol of the French intelligentsia while still in his early twenties His versatile mind was sparkling; his wit was mordant An outspoken critic, he soon ran afoul of both church and state authorities First he was imprisoned in the Bastille; later he was exiled to England There he encountered the ideas of Newton and Locke and came to admire English parliamentary government and tolerance In Letters on the English (1732), Elements of the Philosophy of Newton (1738), and other writings, he popularized the ideas of Newton and Locke, extolled the virtues of English society, and indirectly criticized French society Slipping back into France, he was hidden for a time and protected by a wealthy woman who became his mistress Voltaire’s facile mind and pen were never idle He wrote poetry, drama, history, essays, letters, and scientific treatises— ninety volumes in all Few people in history have dominated their age intellectually as did Voltaire [80] [85] [90] [95] [100] [105] [110] [115] 99 According to the passage, the philosophes can best be described as: A writers swept up by their mutual admiration of John Locke B professors who lectured in philosophy at French universities C intellectuals responsible for popularizing Enlightenment ideas D scientists who furthered the work of the Scientific Revolution 100 Based on information provided in the passage, which of the following would most likely have been written by Voltaire? F A treatise criticizing basic concepts of the Scientific Revolution G A play satirizing society in France H A collection of letters mocking the English Parliament J A sentimental poem expounding the virtues of courtly love 101 According to the passage, Locke felt that schools and social institutions could “play a great role in molding the individual” (lines 58-59) because: A human beings were born with certain innate ideas B human nature becomes more malleable with age C society owes each individual the right to an education D the human mind is chiefly influenced by experience 102 Based on the information in the passage, which of the following best describes Newton’s view of the universe? I -The universe was initially set in motion by God II -Human reason is insufficient to understand the laws of nature III -The universe operates in a mechanical and orderly fashion F I only G I and II only H I and III only J II and III only 103 According to the passage, which of the following works questioned the idea that revelation was a reliable source of truth? A Letters on the English B Second Treatise of Civil Government C Elements of the Philosophy of Newton D Essay Concerning Human Understanding 104 The passage supports which of the following statements concerning the relationship between Newton and Locke? F Locke’s psychology contradicted Newton’s belief in an orderly universe G Locke maintained that Newton’s laws of the material universe also applied to the human mind H Newton eventually came to accept Locke’s revolutionary ideas about the human mind J Newton’s political ideas were the basis of Locke’s liberal and reformist politics 105 According to the passage, the philosophes believed that society should: I -allow individuals greater freedom II -free itself from traditional institutions III -tolerate religious differences A I only B I and II only C II and III only D I, II, and III 106 It can be inferred from the passage that the authors regard England’s political stability and economic prosperity as: F the reason that the philosophes did not idealize England’s achievement G evidence that political reforms could bring about a better way of life H the result of Voltaire’s activities after he was exiled to England J an indication that the Scientific Revolution had not yet started there 107 The passage suggests that the French political and religious authorities during the time of Voltaire: A allowed little in the way of free speech B overreacted to Voltaire’s mild satires C regarded the philosophes with indifference D accepted the model of English parliamentary government 108 As it is used in the passage, treatises (line 115) most nearly means: F formal agreements about trade or peace made between two or more countries G extensive written discussions or examinations of specific topics H documents detailing agreements on specific issues J narratives designed to teach moral lessons Passage XIV NATURAL SCIENCE: This passage is taken from “The Quasar 3C 273” by Thierry Courvoisier and E Ian Robinson It originally appeared in Scientific American, June 1991, Volume 264 Reprinted by permission The quasar 3C 273 lies about one-fifth of the way from the Earth to the edge of the known universe Of all the objects in the cosmos, only a few other quasars surpass the energy and activity of 3C 273 On an average day, it is more luminous than 1,000 galaxies, each containing 100 billion stars During one remarkable day in February, 1988, the quasar erupted with a burst of radiation equivalent to lighting up stars the size of our sun at the rate of 10 million per second By monitoring 3C 273 in all domains of the electromagnetic spectrum and by observing variations in its luminosity, astronomers have begun to understand quasars and the physical processes that power them Since quasars were first identified some 28 years ago, astronomers have come to realize that quasars are the cores of extremely active galaxies Quasars are unmatched in luminosity and hence are the most distant objects that can be detected in the universe One of the most important discoveries about quasars is that their luminosity can vary greatly over periods of less than a year This variability led investigators to the conclusion that the tremendous energy of quasars is radiated from a region many times smaller than the cores of ordinary galaxies Quasars are powered by the gravitational energy that is released as gas and dust fall toward their massive, dense centers Some of this energy channels particles into beams, blasting material out into the host galaxy at speeds close to that of light Most of the energy is converted into radiation by a wide range of physical processes, probably occurring at different distances from the core Yet quasars exhibit many phenomena that cannot be explained, and they remain one of the most puzzling objects in the universe [5] [10] [15] [20] [25] [30] [35] [40] On the whole, we know more about 3C 273 than any other quasar It possesses a very wide range of properties, not all of which are shared by all quasars The wealth of activity displayed by 3C 273, however, is a key in helping astronomers understand the phenomena at work in quasars The task of observing 3C 273 is as challenging as it is rewarding After traveling through space for more than a billion years, only a tiny fraction of the radiation from 3C 273 reaches the Earth Capturing this radiation requires frequent observations using a battery of ground-based telescopes and satellite-borne instruments The effort began more than a century ago The object known today as 3C 273 was first recorded on photographic plates as astronomers surveyed the stars in the constellation Virgo It looked like nothing more than an ordinary, moderately bright star Then in 1962, Cyril Hazard and his colleagues at Sydney University discovered that the starlike object occupied the same position in the sky as a strong source of radio waves The radio emitter had been previously identified as 3C 273, which stood for number 273 in the Third Cambridge Catalogue of Radio Sources Objects such as 3C 273 were subsequently described as quasistellar radio sources, or quasars In 1963, Maarten Schmidt of the Mount Wilson and Palomar Observatories deduced that the quasar 3C 273 was about three billion light-years away from the Earth The implications of this discovery were extraordinary The quasar was by far the most luminous and distant object ever observed Soon a few other quasars were identified that seemed to be even farther and brighter than 3C 273 At the time, many of Schmidt’s colleagues had good reason to question these results Yet as modern [45] [50] [55] [60] [65] [70] [75] [80] [85] astronomers review the evidence collected during the past 28 years, we find little room to doubt that Schmidt was right 109 According to the passage, astronomers study quasars and the physical processes that power them by: A observing 3C 273 through ground-based telescopes B monitoring the electromagnetic spectrum of 3C 273 C enlarging satellite photographs of distant galaxies D investigating phenomena that cannot be easily explained 110 According to the passage, what characteristic of quasars makes them the most distant objects that can be detected in the universe? F Their density G Their size H Their luminosity J Their puzzling behavior 111 According to the passage, which of the following describes a characteristic of quasars? I.-They blast material out into host galaxies II.-They convert gravitational energy into radiation III -They possess cores the size of ordinary galaxies A I only B I and II only C II and III only D I, II, and III 112 The passage suggests that observing 3C 273 is as “challenging as it is rewarding” (lines 51-52) because: F there are many unexplained phenomena related to quasars G very little radiation from 3C 273 actually reaches the Earth H scientists have been attempting to study 3C 273 for over a century J the technology required to observe 3C 273 is still being developed 113 As it is used in line 46, the word properties most likely means: A characteristics B possessions C objects D resources 114 The passage suggests that which of the following is true concerning the growth of scientific knowledge about quasars? F Despite some early skepticism, scientists today still believe that Schmidt’s conclusions are accurate G While Hazard’s discovery was immediately accepted, Schmidt’s deductions were ridiculed by his colleagues H Although Hazard’s discovery has proved significant, much remains questionable regarding Schmidt’s deductions from that data J While Hazard’s discovery was an accident, Schmidt’s discovery was the result of careful analysis 115 From the passage, it is most reasonable to conclude that observers originally thought that quasar 3C 273 was: A a radio emitter B a nearby galaxy C an ordinary star D a typical quasar 116 In the passage, which of the following is NOT a fact provided about quasar 3C 237? F It is typically more luminous than 1,000 galaxies G Its luminosity can vary, with some extreme peaks of radiation production H All quasars have the same properties as 3C 237 J Radiation from 3C 237 takes more than a billion years to reach Earth Passage XV NATURAL SCIENCE: The following passage is excerpted from “The Transformer” by John W Coltman (©1988 by Scientific American.) The transformer is an essential component of modern electric power systems Simply put, it can convert electricity with a low current and a high voltage into electricity with a high current and low voltage (and vice versa) with almost no loss of energy The conversion is important because electric power is transmitted most efficiently at high voltages but is best generated and used at low voltages Were it not for transformers, the distance separating generators from consumers would have to be minimized, many households and industries would require their own power stations, and electricity would be a much less practical form of energy In addition to its role in electric power systems, the transformer is an integral component of many things that run on electricity Desk lamps, battery chargers, toy trains, and television sets all rely on transformers to cut or boost voltage In all its multiplicity of applications, the transformer can range from tiny assemblies the size of a pea to behemoths weighing 500 tons or more This article will focus on the transformers in power systems, but the principles that govern the function of electrical transformers are the same regardless of form or application The English physicist Michael Faraday discovered the basic action of the transformer during his pioneering investigations of electricity in 1831 Some fifty years later, the advent of a practical transformer, containing all the essential elements of the modern instrument, revolutionized the infant electric lighting industry By the turn of the century, alternating-current power systems had been universally adopted and [5] [10] [15] [20] [25] [30] [35] the transformer had assumed a key role in electrical transmission and distribution Yet the transformer’s tale does not end in 1900 Today’s transformers can handle 500 times the power and 15 times the voltage of their turn-of-the-century ancestors; the weight per unit of power has dropped by a factor of ten and efficiency typically exceeds 99 percent These advances reflect the marriage of theoretical inquiry and engineering that first elucidated and then exploited the phenomena governing transformer action Faraday’s investigations were inspired by the Danish physicist Hans Christian Oersted, who had shown in 1820 that an electric current flowing through a conducting material creates a magnetic field around the conductor At the time, Oersted’s discovery was considered remarkable, since electricity and magnetism were thought to be separate and unrelated forces If an electric current could generate a magnetic field, it seemed likely that a magnetic field could give rise to an electric current In 1831, Faraday demonstrated that in order for a magnetic field to induce a current in a conductor, the field must be changing Faraday caused the strength of the field to fluctuate by making and breaking the electric circuit generating the field; the same effect can be achieved with a current whose direction alternates in time This fascinating interaction of electricity and magnetism came to be known as electromagnetic induction [40] [45] [50] [55] [60] [65] [70] [75] 117 According to the passage, the first practical transformer was developed in: A 1820 B 1831 C 1881 D 1900 118 The passage suggests that advances in the efficiency of the transformer are: F based solely on Faraday’s discovery of electromagnetic induction G due to a combination of engineering and theoretical curiosity H most likely at a peak that cannot be surpassed J found in transformers that weigh 500 tons or more 119 According to the passage, Oersted’s discovery concerning the production of a magnetic field was considered remarkable because: A the transformer had not yet been universally adopted B Faraday had already demonstrated that this was impossible C scientists believed that there was no relationship between electricity and magnetism D it contradicted the established principles of electromagnetism 120 Which of the following is NOT true of transformers today as compared to the first transformers? F they are lighter in weight G they are many times more powerful H they operate at a much lower voltage J they are almost completely efficient 121 According to the passage, Oersted’s discovery proved that: A magnetism and electricity are unrelated forces B a magnetic field can induce an electric current C all materials that conduct electricity are magnetic D an electric current can create a magnetic field 122 According to the passage, one function of the transformer is to: F convert electricity into the high voltages best for transmission G create the magnetic fields used in industry H minimize the distance between generators and consumers J protect electric power systems from energy loss 123 Which of the following statements is best supported by the passage? A Faraday was the first to show how an electric current can induce an electric field B Oersted was the first to utilize transformers in a practical application, by using them to power electric lights C Oersted coined the term “electromagnetic induction.” D Faraday demonstrated that when a magnetic field is changing, it can produce an electric current in a conducting material 124 According to the passage, electricity would be a much less practical form of energy if there were no transformers because: F G H J generating electricity would become much more expensive there would be no dependable source of electric power generators would have to be built close to the consumers they supply industries and households would have to be supplied with the same power Passage XVI NATURAL SCIENCE: This passage from a textbook about the solar system discusses research examining the possibility of life on Mars When the first of the two Viking Landers touched down on Martian soil on July, 1976, and began to send camera images back to Earth, the scientists at the Jet Propulsion Laboratory could not suppress a certain nervous anticipation, like people who hold a ticket to a lottery they have a one-in-a-million chance of winning The first photographs that arrived, however, did not contain any evidence of life What was revealed was merely a barren landscape littered with rocks and boulders The view resembled nothing so much as a flat section of desert— in fact, the winning entry in a contest at J.P.L for the photograph most accurately predicting what Mars would look like was a snapshot taken from a particularly arid section of the Mojave Desert The scientists were soon ready to turn their attention from visible life to microorganisms The twin Viking Landers carried experiments designed to detect organic compounds Researchers thought it possible that life had developed on early Mars just as it is thought to have developed on Earth, through the gradual chemical evolution of complex organic molecules To detect biological activity, Martian soil samples were treated with various nutrients that would produce characteristic by-products if life forms were active in the soil The results from all three [5] [10] [15] [20] [25] [30] experiments were inconclusive The fourth experiment heated a soil sample to look for signs of organic material but found none, an unexpected result because at least organic compounds from the steady bombardment of the Martian surface by meteorites were thought to have been present The absence of organic materials, some scientists speculated, was the result of intense ultraviolet radiation penetrating the atmosphere of Mars and destroying organic compounds in the soil Although Mars’ atmosphere was at one time rich in carbon dioxide and thus thick enough to protect its surface from the harmful rays of the Sun, the carbon dioxide had gradually left the atmosphere and been converted into rocks This means that even if life had gotten a start on early Mars, it could not have survived the exposure to ultraviolet radiation when the atmosphere thinned Mars never developed a protective layer of ozone as Earth did Despite the disappointing Viking results, there are those who still keep open the possibility of life on Mars They point out that the Viking data cannot be considered the final word on Martian life because the two landers only sampled limited—and uninteresting—sites The Viking landing sites were not chosen for what they might tell of the planet’s biology They were chosen primarily because they appeared to be safe for landing a spacecraft The landing sites were on parts of the Martian plains that appeared relatively featureless from orbital photographs The type of terrain that these researchers suggest may be a possible hiding place for active life has an Earthly parallel: the ice-free region of southern Victoria Land, Antarctica, where the temperatures in some dry valleys average below zero Organisms known as endoliths, a form of blue- [35] [40] [45] [50] [55] [60] [65] [70] green algae that has adapted to this harsh environment, were found living inside certain translucent, porous rocks in these Antarctic valleys The argument based on this discovery is that if life did exist on early Mars, it is possible that it escaped worsening conditions by similarly seeking refuge in rocks Skeptics object, however, that Mars in its present state is simply too dry, even compared with Antarctic valleys, to sustain any life whatsoever Should Mars eventually prove to be barren of life, as some suspect, then this would have a significant impact on the current view of the chemical origins of life It could be much more difficult to get life started on a planet than scientists thought before the Viking landings [75] [80] [85] [90] 125 The word suppress, as used in line 5, most nearly means: A oppose B vanquish C prohibit D stifle 126 According to the passage, scientists treated Martian soil samples with nutrients in order to: F test for the presence of life-forms G verify the results of their experiments H investigate ways of starting life on other planets J find evidence of meteorite bombardment 127 According to the passage, scientists expected organic compounds to be present on Mars as a result of: A alien civilizations B ultraviolet radiation C meteor bombardment D atmospheric activity 128 The passage suggests that an important difference between Mars and Earth is that, unlike Earth, Mars: F accumulated organic compounds in its soil G lies in the path of harmful rays of ultraviolet radiation H once possessed an atmosphere rich in carbon dioxide J could not sustain any life that developed 129 According to the passage, the surface of Mars most resembles: A southern Florida B the Mojave desert C southern Victoria Land D the ice valleys of Antarctica 130 The main point of the second paragraph (lines 19-38) is that: F scientists were disappointed by the inconclusive results of their experiments G theories about how life developed on Earth were shown to be flawed H there was no experimental confirmation that life exists on Mars J meteorite bombardment of the Martian surface is less constant than scientists predicted 131 The researchers’ argument that life may exist in Martian rocks rests on the idea that: A life evolved in the same way on two different planets B organisms may adopt identical survival strategies in similar environments C life developed in the form of a blue-green algae on Mars D organisms that survived in Antarctica could survive on Mars 132 According to the passage, the results of the Viking Mission could eventually have a “significant impact” (line 88) because: F future expeditions to Mars may take samples from many different sites G current theories about how life began on Earth may have to be changed H scientists may be forced to acknowledge that life does not exist on other planets J the focus of research into the evolution of life may shift to Antarctica 133 According to the passage, any organic materials that existed on Mars were probably destroyed by: I.-ultraviolet radiation II.-carbon dioxide in the atmosphere III -the absence of a layer of ozone A I only B I and II only C I and III only D I, II, and III 134 Which of the following statements is best supported by the fourth paragraph (lines 54-67)? F The Viking Mission was unsuccessful due to poor selection of landing sites G The results of the Viking mission not prove that Mars is devoid of life H The detection of life on Mars was not a primary objective of the Viking mission J Scientists were not expecting to discover life on the Martian plains Passage XVII NATURAL SCIENCE: The following passage is excerpted from “Earth’s Ozone Shield Under Threat” by France Bequette (© Unesco Courier, June 1990) The ozone layer, the tenuous layer of gas that surrounds our planet between twelve and forty-five kilometers above our surface, is being rapidly depleted Seasonally occurring holes have appeared in it over the Poles, and, more recently, over the temperate regions of the Northern Hemisphere The threat is a serious one since the ozone layer traps almost all in-coming ultraviolet radiation, which is harmful to all living organisms—humans, animals, and plants Even though the ozone layer is twentyfive kilometers thick, the atmosphere in it is very tenuous, and the total amount of ozone, compared with other atmospheric gases, is quite small If all of the ozone in a vertical column reaching up through the atmosphere were to be compressed to sealevel pressure, it would form a layer only a few millimeters thick Detailed study of the ozone layer began comparatively recently, the earliest observations being made in 1930 by the English scientist Sydney Chapman These initial observations were taken up by the World Meteorological Organization (WMO), which established the Dobson network of one hundred observation stations Since 1983, on the initiative of WMO and the United Nations Environment Programme (UNEP), [5] [10] [15] [20] [25] [30] seven of these stations have been entrusted with the task of making long-term forecasts of the likely evolution of our precious shield In 1958, the researchers who permanently monitor the ozone content of the layer above the South Pole began to observe several seasonal variations From June there was a slight reduction in ozone content that reached a minimum in October In November, there was a sudden increase in the ozone content The fluctuations appeared to result from the natural phenomena of wind effects and temperature change [35] However, although the October minimum remained constant until 1979, the total ozone content over the Pole was steadily diminishing until, in 1985, public opinion was finally roused by reports of a “hole” in the ozone layer and observations were intensified The culprits responsible for the hole had already been identified as being supersonic aircraft, such as Concorde, (although these have now been exonerated) and the notorious compounds known as chlorofluorocarbons, or CFCs Synthesized in 1928 by chemists working at General Motors in the United States, CFCs are compounds of atoms of chlorine and fluorine Having the advantage of being non-flammable, non-toxic and non-corrosive, they came into widespread use in the 1950s They are widely used in refrigerators, airconditioners, the “bubbles” in the foam plastic used, for example, in car seats, and as insulation in buildings… [45] In 1989, they represented a market valued at over $1.5 billion and a labor force of 1.6 million Of the twenty-five countries producing CFCs, the United States, France, the United Kingdom, Japan and Germany accounted for three-quarters of the total world production of some 1.2 million tons [40] [50] [55] [60] [65] [70] These figures give some idea of the importance of the economic interests that are at stake in any decision to ban the industrial use of CFCs But, with CFCs incriminated by scientists, the question arose as to whether we were prepared to take the risk of seeing an increase in the number of cases of skin cancer, eye ailments such as cataracts, or even a lowering of the human immune defense system, all effects that would follow further depletion of the ozone layer… Ozone Layer was the first world agreement aimed at halting the production of CFCs As more evidence emerged concerning the seriousness of the threat, it became apparent that the protocol was not stringent enough and, year by year, its severity was increased until in 1990 in London, seventy countries agreed to stop all production of CFCs by the year 2000… Unfortunately, even if the entire world were to agree today to halt all production and use of CFCs, this would not provide an immediate solution to the problem A single molecule of chlorine can destroy from 10,000 to 100,000 molecules of ozone Furthermore, CFCs have a lifespan of between 75 and 400 years, and they take ten years to reach the ozone layer In other words, what we are experiencing now results from CFCs emitted ten years ago Industrialists are now urgently searching for substitute products Some, such as propane, are too dangerous because they are flammable; others, the HCFCs, might prove to be toxic and to contribute to the greenhouse effect, i.e., to the process of global warming Nevertheless, nobody can say that the situation will not right itself, whether in the short term or long term, if we ourselves lend a hand [75] [80] [85] [90] [95] [100] [105] [110] [115] 135 As it is used in the passage, the term tenuous (lines and 14) most likely means: A thin B dangerous C substantial D fragile 136 According to the passage, the public first became aware of the depletion of ozone layer in: F 1930 G 1958 H 1979 J 1985 137 According to the passage, all of the following contribute to fluctuations in the content of the ozone layer EXCEPT: A supersonic aircraft B chlorofluorocarbons C temperature changes D wind effects 138 The main point of the seventh paragraph (lines 67-73) is to: F highlight the amount of CFCs produced every year G criticize the countries responsible for producing CFCs H indicate the economic interests at stake in the CFC debate J list the most important members of the Montreal Protocol 139 According to the passage, alternatives to using CFCs may be difficult to find because substitute products I may prove to be toxic II are too dangerous to use III contribute to global warming A B C D II only II and III only I and II only I, II, and III 140 According to the passage, forecasts about the future of the ozone layer are made by: F the WMO G the Dobson network H the Montreal Protocol J the UNEP 141 Based on information in the passage, which of the following would be the most likely result if all production of CFCs were to end today? A Scientists would have to replace the quantities of ozone already lost B The ozone layer would only return to normal levels after 75 years C Scientists would also have to destroy all chlorine molecules in the atmosphere D The benefits would not be experienced for another ten years 142 According the passage, the ozone layer is: F a few millimeters thick G twelve kilometers thick H twenty-five kilometers thick J over twenty-five kilometers thick 143 Which of the following statements is best supported by the fourth paragraph (lines 35-44)? A The ozone layer undergoes seasonal variations in density B The number of CFCs in the atmosphere increases from June to October C The ozone layer over the South Pole is more at risk than in other areas D The first studies of ozone layer depletion underestimated its severity 144 The main conclusion reached in the passage about the threat to the ozone layer is that: F the cost of banning CFCs altogether may make it an impractical answer G finding alternative products to CFCs may provide a long-term remedy to the situation H halting production of CFCs is unlikely to produce a solution to the problem J agreements between CFC-producing countries need to be more strictly enforced  ... fascinating interaction of electricity and magnetism came to be known as electromagnetic induction [40 ] [45 ] [50] [55] [60] [65] [70] [75] 117 According to the passage, the first practical transformer... still being developed 113 As it is used in line 46 , the word properties most likely means: A characteristics B possessions C objects D resources 1 14 The passage suggests that which of the following... molecules To detect biological activity, Martian soil samples were treated with various nutrients that would produce characteristic by-products if life forms were active in the soil The results