Final Examination - Reading

Meteorite Impact and Dinosaur Extinction There is increasing evidence that the impacts of meteorites have had important effects on Earth, particularly in the field of biological evolution. Such impacts continue to pose a natural hazard to life on Earth. Twice in the twentieth century, large meteorite objects are known to have collided with Earth. If an impact is large enough, it can disturb the environment of the entire Earth and cause an ecological catastrophe. The best-documented such impact took place 65 million years ago at the end of the Cretaceous period of geological history. This break in Earth’s history is marked by a mass extinction, when as many as half the species on the planet became extinct. While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs. For tens of millions of years, those great creatures had flourished. Then, suddenly, they disappeared. The body that impacted Earth at the end of the Cretaceous period was a meteorite with a mass of more than a trillion tons and a diameter of at least 10 kilometers. Scientists first identified this impact in 1980 from the worldwide layer of sediment deposited from the dust cloud that enveloped the planet after the impact. This sediment layer is enriched in the rare metal iridium and other elements that are relatively abundant in a meteorite but very rare in the crust of Earth. Even diluted by the terrestrial material excavated from the crater, this component of meteorites is easily identified. By 1990, geologists had located the impact site itself in the Yucatán region of Mexico. The crater, now deeply buried in sediment, was originally about 200 kilometers in diameter. This impact released an enormous amount of energy, excavating a crater about twice as large as the lunar crater Tycho. The explosion lifted about 100 trillion tons of dust into the atmosphere, as can be determined by measuring the thickness of the sediment layer formed when this dust settled to the surface. Such a quantity of material would have blocked the sunlight completely from reaching the surface, plunging Earth into a period of cold and darkness that lasted at least several months. The explosion is also calculated to have produced vast quantities of nitric acid and melted rock that sprayed out over much of Earth, starting widespread fires that must have consumed most terrestrial forests and grassland. Presumably, those environmental disasters could have been responsible for the mass extinction, including the death of the dinosaurs. Several other mass extinctions in the geological record have been tentatively identified with large impacts, but none is so dramatic as the Cretaceous event. But even without such specific documentation, it is clear that impacts of this size do occur and that their results can be catastrophic. What is a catastrophe for one group of living things, however, may create opportunities for another group. Following each mass extinction, there is a sudden evolutionary burst as new species develop to fill the ecological niches opened by the event. Impacts by meteorites represent one mechanism that could cause global catastrophes and seriously influence the evolution of life all over the planet. According to some estimates, the majority of all extinctions of species may be due to such impacts. Such a perspective fundamentally changes our view of biological evolution. The standard criterion for the survival of a species is its success in competing with other species and adapting to slowly changing environments. Yet an equally important criterion is the ability of a species to survive random global ecological catastrophes due to impacts. Earth is a target in a cosmic shooting gallery, subject to random violent events that were unsuspected a few decades ago. In 1991, the United States Congress asked NASA to investigate the hazard posed today by large impacts on Earth. The group conducting the 55 study concluded from a detailed analysis that impacts from meteorites can indeed be hazardous. Although there is always some risk that a large impact could occur, careful study shows that this risk is quite small.

Running Water on Mars? Photographic evidence suggests that liquid water once existed in great quantity on the surface of Mars. Two types of flow features are seen: runoff channels and outflow channels. Runoff channels are found in the southern highlands. These flow features are extensive systems—sometimes hundreds of kilometers in total length—of interconnecting, twisting channels that seem to merge into larger, wider channels. They bear a strong resemblance to river systems on Earth, and geologists think that they are dried-up beds of long-gone rivers that once carried rainfall on Mars from the mountains down into the valleys. Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread. Outflow channels are probably relics of catastrophic flooding on Mars long ago. (A) They appear only in equatorial regions and generally do not form extensive interconnected networks.(B) Instead, they are probably the paths taken by huge volumes of water draining from the southern highlands into the northern plains.(C) The onrushing water arising from these flash floods likely also formed the odd teardrop-shaped “islands” (resembling the miniature versions seen in the wet sand of our beaches at low tide) that have been found on the plains close to the ends of the outflow channels. (D) Judging from the width and depth of the channels, the flow rates must have been truly enormous—perhaps as much as a hundred times greater than the 105 tons per second carried by the great Amazon river. Flooding shaped the outflow channels approximately 3 billion years ago, about the same time as the northern volcanic plains formed. Some scientists speculate that Mars may have enjoyed an extended early period during which rivers, lakes, and perhaps even oceans adorned its surface. A 2003 Mars Global Surveyor image shows what mission specialists think may be a delta—a fan-shaped network of channels and sediments where a river once flowed into a larger body of water, in this case a lake filling a crater in the southern highlands. Other researchers go even further, suggesting that the data provide evidence for large open expanses of water on the early Martian surface. A computer-generated view of the Martian north polar region shows the extent of what may have been an ancient ocean covering much of the northern lowlands. The Hellas Basin, which measures some 3,000 kilometers across and has a floor that lies nearly 9 kilometers below the basin’s rim, is another candidate for an ancient Martian sea. These ideas remain controversial. Proponents point to features such as the terraced “beaches” shown in one image, which could conceivably have been left behind as a lake or ocean evaporated and the shoreline receded. But detractors maintain that the terraces could also have been created by geological activity, perhaps related to the geologic forces that depressed the Northern Hemisphere far below the level of the south, in which case they have nothing whatever to do with Martian water. Furthermore, Mars Global Surveyor data released in 2003 seem to indicate that the Martian surface contains too few carbonate rock layers—layers containing compounds of carbon and oxygen—that should have been formed in abundance in an ancient ocean. Their absence supports the picture of a cold, dry Mars that never experienced the extended mild period required to form lakes and oceans. However, more recent data imply that at least some parts of the planet did in fact experience long periods in the past during which liquid water existed on the surface. Aside from some small-scale gullies (channels) found since 2000, which are inconclusive, astronomers have no direct evidence for liquid water anywhere on the surface of Mars today, and the amount of water vapor in the Martian atmosphere is tiny. Yet even setting aside the unproven hints of ancient oceans, the extent of the outflow channels suggests that a huge total volume of water existed on Mars in the past. Where did all the water go? The answer may be that virtually all the water on Mars is now locked in the permafrost layer under the surface, with more contained in the planet’s polar caps.

Ancient Rome and Greece There is a quality of cohesiveness about the Roman world that applied neither to Greece nor perhaps to any other civilization, ancient or modern. Like the stones of a Roman wall, which were held together both by the regularity of the design and by that peculiarly powerful Roman cement, so the various parts of the Roman realm were bonded into a massive, monolithic entity by physical, organizational, and psychological controls. The physical bonds included the network of military garrisons, which were stationed in every province, and the network of stone-built roads that linked the provinces with Rome. The organizational bonds were based on the common principles of law and administration and on the universal army of officials who enforced common standards of conduct. The psychological controls were built on fear and punishment—on the absolute certainty that anyone or anything that threatened the authority of Rome would be utterly destroyed. The source of the Roman obsession with unity and cohesion may well have lain in the pattern of Rome’s early development. Whereas Greece had grown from scores of scattered cities, Rome grew from one single organism. While the Greek world had expanded along the Mediterranean sea lanes, the Roman world was assembled by territorial conquest. Of course, the contrast is not quite so stark: in Alexander the Great the Greeks had found the greatest territorial conqueror of all time; and the Romans, once they moved outside Italy, did not fail to learn the lessons of sea power. Yet the essential difference is undeniable. The key to the Greek world lay in its high-powered ships; the key to Roman power lay in its marching legions. The Greeks were wedded to the sea; the Romans, to the land. The Greek was a sailor at heart; the Roman, a landsman. Certainly, in trying to explain the Roman phenomenon, one would have to place great emphasis on this almost animal instinct for the territorial imperative. Roman priorities lay in the organization, exploitation, and defense of their territory. In all probability it was the fertile plain of Latium, where the Latins who founded Rome originated, that created the habits and skills of landed settlement, landed property, landed economy, landed administration, and a land-based society. From this arose the Roman genius for military organization and orderly government. In turn, a deep attachment to the land, and to the stability which rural life engenders, fostered the Roman virtues: gravitas, a sense of responsibility, peitas, a sense of devotion to family and country, and iustitia, a sense of the natural order. Modern attitudes to Roman civilization range from the infinitely impressed to the thoroughly disgusted. (A) As always, there are the power worshippers, especially among historians, who are predisposed to admire whatever is strong, who feel more attracted to the might of Rome than to the subtlety of Greece. (B) At the same time, there is a solid body of opinion that dislikes Rome. (C) For many, Rome is at best the imitator and the continuator of Greece on a larger scale. (D) Greek civilization had quality; Rome, mere quantity. Greece was original; Rome, derivative. Greece had style; Rome had money. Greece was the inventor; Rome, the research and development division. Such indeed was the opinion of some of the more intellectual Romans. “Had the Greeks held novelty in such disdain as we,” asked Horace in his Epistles, “what work of ancient date would now exist?” Rome’s debt to Greece was enormous. The Romans adopted Greek religion and moral philosophy. In literature, Greek writers were consciously used as models by their Latin successors. It was absolutely accepted that an educated Roman should be fluent in Greek. In speculative philosophy and the sciences, the Romans made virtually no advance on early achievements. Yet it would be wrong to suggest that Rome was somehow a junior partner in GrecoRoman civilization. The Roman genius was projected into new spheres—especially into those of law, military organization, administration, and engineering. Moreover, the tensions that arose within the Roman state produced literary and artistic sensibilities of the highest order. It was no accident that many leading Roman soldiers and statesmen were writers of high caliber.

History of the Chickenpox Vaccine Chickenpox is a highly contagious infectious disease caused by the Varicella zoster virus; sufferers develop a fleeting itchy rash that can spread throughout the body. The disease can last for up to 14 days and can occur in both children and adults, though the young are particularly vulnerable. Individuals infected with chickenpox can expect to experience a high but tolerable level of discomfort and a fever as the disease works its way through the system. The ailment was once considered to be a “rite of passage” by parents in the U.S. and thought to provide children with greater and improved immunity to other forms of sickness later in life. This view, however, was altered after additional research by scientists demonstrated unexpected dangers associated with the virus. Over time, the fruits of this research have transformed attitudes toward the disease and the utility of seeking preemptive measures against it. A vaccine against chickenpox was originally invented by Michiaki Takahashi, a Japanese doctor and research scientist, in the mid-1960s. Dr. Takahashi began his work to isolate and grow the virus in 1965 and in 1972 began clinical trials with a live but weakened form of the virus that caused the human body to create antibodies. Japan and several other countries began widespread chickenpox vaccination programs in 1974. However, it took over 20 years for the chickenpox vaccine to be approved by the U.S. Food & Drug Administration (FDA), finally earning the U.S. government’s seal of approval for widespread use in 1995. Yet even though the chickenpox vaccine was available and recommended by the FDA, parents did not immediately choose to vaccinate their children against this disease. Mothers and fathers typically cited the notion that chickenpox did not constitute a serious enough disease against which a person needed to be vaccinated. Strong belief in that view eroded when scientists discovered the link between Varicella zoster, the virus that causes chickenpox, and shingles, a far more serious, harmful, and longer-lasting disease in older adults that impacts the nervous system. They reached the conclusion that Varicella zoster remains dormant inside the body, making it significantly more likely for someone to develop shingles. As a result, the medical community in the U.S. encouraged the development, adoption, and use of a vaccine against chickenpox to the public. Although the appearance of chickenpox and shingles within one person can be many years apart—generally many decades—the increased risk in developing shingles as a younger adult (30-40 years old rather than 60-70 years old) proved to be enough to convince the medical community that immunization should be preferred to the traditional alternative. Another reason that the chickenpox vaccine was not immediately accepted and used by parents in the U.S. centered on observations made by scientists that the vaccine simply did not last long enough and did not confer a lifetime of immunity. In other words, scientists considered the benefits of the vaccine to be temporary when given to young children. They also feared that it increased the odds that a person could become infected with chickenpox later as a young adult, when the rash is more painful and prevalent and can last up to three or four weeks. Hence, allowing young children to develop chickenpox rather than take a vaccine against it was believed to be the “lesser of two evils.” This idea changed over time as booster shots of the vaccine elongated immunity and countered the perceived limits on the strength of the vaccine itself. Today, use of the chickenpox vaccine is common throughout the world. Pediatricians suggest an initial vaccination shot after a child turns one year old, with booster shots recommended after the child turns eight. The vaccine is estimated to be up to 90% effective and has reduced worldwide cases of chickenpox infection to 400,000 cases per year from over 4,000,000 cases before vaccination became widespread. ■ (A) ​In light of such statistics, most doctors insist that the potential risks of developing shingles outweigh the benefits of avoiding rare complications associated with inoculations. ■ (B) Of course, ​many parents continue to think of the disease as an innocuous ailment, refusing to take preemptive steps against it. ■ (C) ​As increasing numbers of students are vaccinated and the virus becomes increasingly rarer, however, even this trend among parents has failed to halt the decline of chickenpox among the most vulnerable populations. ■ (D)

1. The word “pose” in the passage is closest in meaning to

• A.

  Claim

• B.

  Model

• C.

  Assume

• D.

  Present

2. In paragraph 2, why does the author include the information that dinosaurs had flourished for tens of millions of years and then suddenly disappeared?

• A.

  To support the claim that the mass extinction at the end of the Cretaceous is the best-documented of the dozen or so mass extinctions in the geological record

• B.

  To explain why as many as half of the species on Earth at the time are believed to have become extinct at the end of the Cretaceous

• C.

  To explain why paleontologists have always been intrigued by the mass extinction at the end of the Cretaceous

• D.

  To provide evidence that an impact can be large enough to disturb the environment of the entire planet and cause an ecological disaster

3. Which of the following can be inferred from paragraph 3 about the location of the meteorite impact in Mexico?

• A.

  The location of the impact site in Mexico was kept secret by geologists from 1980 to 1990.

• B.

  It was a well-known fact that the impact had occurred in the Yucatán region.

• C.

  Geologists knew that there had been an impact before they knew where it had occurred.

• D.

  The Yucatán region was chosen by geologists as the most probable impact site because of its climate.

4. According to paragraph 3, how did scientists determine that a large meteorite had impacted Earth?

• A.

  They discovered a large crater in the Yucatán region of Mexico.

• B.

  They found a unique layer of sediment worldwide.

• C.

  They were alerted by archaeologists who had been excavating in the Yucatán region.

• D.

  They located a meteorite with a mass of over a trillion tons.

5. The word “excavating” in the passage is closest in meaning to

• A.

  Digging out

• B.

  Extending

• C.

  Destroying

• D.

  Covering up

6. The word “consumed” in the passage is closest in meaning to

• A.

  Changed

• B.

  Exposed

• C.

  Destroyed

• D.

  Covered

7. According to paragraph 4, all of the following statements are true of the impact at the end of the Cretaceous period EXCEPT:

• A.

  A large amount of dust blocked sunlight from Earth.

• B.

  Earth became cold and dark for several months.

• C.

  New elements were formed in Earth’s crust.

• D.

  Large quantities of nitric acid were produced.

8. The phrase “tentatively identified” in the passage is closest in meaning to

• A.

  Identified after careful study

• B.

  Identified without certainty

• C.

  Occasionally identified

• D.

  Easily identified

9. Paragraph 6 supports which of the following statements about the factors that are essential for the survival of a species?

• A.

  The most important factor for the survival of a species is its ability to compete and adapt to gradual changes in its environment.

• B.

  The ability of a species to compete and adapt to a gradually changing environment is not the only ability that is essential for survival.

• C.

  Since most extinctions of species are due to major meteorite impacts, the ability to survive such impacts is the most important factor for the survival of a species.

• D.

  The factors that are most important for the survival of a species vary significantly from one species to another.

10. Which of the sentences below best expresses the essential information in the following sentence? "Earth is a target in a cosmic shooting gallery, subject to random violent events that were unsuspected a few decades ago." Incorrect choices change the meaning in important ways or leave out essential information.

• A.

  Until recently, nobody realized that Earth is exposed to unpredictable violent impacts from space.

• B.

  In the last few decades, the risk of a random violent impact from space has increased.

• C.

  Since most violent events on Earth occur randomly, nobody can predict when or where they will happen.

• D.

  A few decades ago, Earth became the target of random violent events originating in outer space.

11. The word “merge” in the passage is closest in meaning to

• A.

  Expand

• B.

  Separate

• C.

  Straighten out

• D.

  Combine

12. What does the discussion in paragraph 1 of runoff channels in the southern highlands suggest about Mars?

• A.

  The atmosphere of Mars was once thinner than it is today.

• B.

  Large amounts of rain once fell on parts of Mars.

• C.

  The river systems of Mars were once more extensive than Earth’s.

• D.

  The rivers of Mars began to dry up about 4 billion years ago.

13. The word “relics” in the passage is closest in meaning to

• A.

  Remains

• B.

  Sites

• C.

  Requirements

• D.

  Sources

14. The word “miniature” in the passage is closest in meaning to

• A.

  Temporary

• B.

  Small

• C.

  Multiple

• D.

  Familiar

15. In paragraph 2, why does the author include the information that 105 tons of water flow through the Amazon River per second?

• A.

  To emphasize the great size of the volume of water that seems to have flowed through Mars’ outflow channels

• B.

  To indicate data used by scientists to estimate how long ago Mars’ outflow channels were formed

• C.

  To argue that flash floods on Mars may have been powerful enough to cause tear-shaped “islands” to form

• D.

  To argue that the force of flood waters on Mars was powerful enough to shape the northern volcanic plains

16. All of the following questions about geological features on Mars are answered in paragraph 3 EXCEPT:

• A.

  What are some regions of Mars that may have once been covered with an ocean?

• B.

  Where do mission scientists believe that the river forming the delta emptied?

• C.

  Approximately how many craters on Mars do mission scientists believe may once have been lakes filled with water?

• D.

  During what period of Mars’ history do some scientists think it may have had large bodies of water?

17. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

• A.

  But detractors argue that geological activity may be responsible for the water associated with the terraces.

• B.

  But detractors argue that the terraces may have been formed by geological activity rather than by the presence of water.

• C.

  But detractors argue that the terraces may be related to geological forces in the Northern Hemisphere of Mars, rather than to Martian water in the south.

• D.

  But detractors argue that geological forces depressed the Northern Hemisphere so far below the level of the south that the terraces could not have been formed by water.

18. According to paragraph 4, what do the 2003 Global Surveyor data suggest about Mars?

• A.

  Ancient oceans on Mars contained only small amounts of carbon.

• B.

  The climate of Mars may not have been suitable for the formation of large bodies of water.

• C.

  Liquid water may have existed on some parts of Mars’ surface for long periods of time.

• D.

  The ancient oceans that formed on Mars dried up during periods of cold, dry weather.

19. The word ‘hints’ in the passage is closet in meaning to

• A.

  Clues

• B.

  Features

• C.

  Arguments

• D.

  Effects

20. In paragraph 2 of the passage, there is a missing sentence. The paragraph is repeated below and shows four letters (A, B, C, and D) that indicate where the following sentence could be added. These landscape features differ from runoff channels in a number of ways. Where would the sentence best fit?

• A.

  A

• B.

  B

• C.

  C

• D.

  D

21. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

• A.

  The regularity and power of stone walls inspired Romans attempting to unify the parts of their realm.

• B.

  Although the Romans used different types of designs when building their walls, they used regular controls to maintain their realm.

• C.

  Several types of control united the Roman realm, just as design and cement held Roman walls together.

• D.

  Romans built walls to unite the various parts of their realm into a single entity, which was controlled by powerful laws.

22. According to paragraph 1, all of the following are controls that held together the Roman world EXCEPT:

• A.

  Administrative and legal systems

• B.

  The presence of the military

• C.

  common language

• D.

  Transportation networks

23. The phrase “obsession with” in the passage is closest in meaning to

• A.

  Thinking about

• B.

  Fixation on

• C.

  Interest in

• D.

  Attitude toward

24. According to paragraph 2, which of the following was NOT characteristic of Rome’s early development?

• A.

  Expansion by sea invasion

• B.

  Territorial expansion

• C.

  Expansion from one original settlement

• D.

  Expansion through invading armies

25. Why does the author mention “Alexander the Great” in the passage?

• A.

  To acknowledge that Greek civilization also expanded by land conquest

• B.

  To compare Greek leaders to Roman leaders

• C.

  To give an example of a Greek leader whom Romans

• D.

  To indicate the superior organization of the Greek military

26. The word “fostered” in the passage is closest in meaning to

• A.

  Accepted

• B.

  Combined

• C.

  Introduced

• D.

  Encouraged

27. Paragraph 3 suggests which of the following about the people of Latium?

• A.

  Their economy was based on trade relations with other settlements.

• B.

  They held different values than the people of Rome.

• C.

  Agriculture played a significant role in their society.

• D.

  They possessed unusual knowledge of animal instincts.

28. In paragraph 4, the author develops a description of Roman civilization by

• A.

  Comparing the opinions of Roman intellectuals to Greek intellectuals

• B.

  Identifying which characteristics of Roman civilization were copied from Greece

• C.

  Explaining how the differences between Rome and Greece developed as time passed

• D.

  Contrasting characteristics of Roman civilization with characteristics of Greek civilization

29. Which of the following statements about leading Roman soldiers is supported by paragraphs 5 and 6?

• A.

  They could read and write the Greek language.

• B.

  They frequently wrote poetry and plays.

• C.

  They focused their writing on military matters.

• D.

  They wrote according to the philosophical laws of the Greeks.

30. In paragraph 4 of the passage, there is a missing sentence. The paragraph is repeated below and shows four letters (A, B, C, and D) that indicate where the following sentence could be added. " They esteem symbols of Roman power, such as the massive Colosseum." Where would the sentence best fit?

• A.

  A

• B.

  B

• C.

  C

• D.

  D

31. The word ‘tolerable’ in the passage is closest in meaning to

• A.

  Sudden

• B.

  Bearable

• C.

  Infrequent

• D.

  Unexpected

32. According to paragraph 1, which of the following is true of the chickenpox virus?

• A.

  It leads to a potentially deadly disease in adults.

• B.

  It is associated with a possibly permanent rash.

• C.

  It is easily transmittable by an infected individual.

• D.

  It has been virtually eradicated in the modern world.

33. Which of the following best expresses the essential information in the highlighted sentence? Incorrect answer choices change the meaning in important ways or leave out essential information.

• A.

  U.S. parents believed that having chickenpox benefited their children.

• B.

  U.S. parents believed that chickenpox led to immunity against most sickness.

• C.

  U.S. parents wanted to make sure that their children developed chickenpox.

• D.

  U.S. parents did not think that other vaccinations were needed after chickenpox.

34. Which of the following can be inferred from paragraph 2 about the clinical trials for the chickenpox vaccine?

• A.

  They took longer than expected.

• B.

  They cost a lot of money to complete.

• C.

  They took a long time to finish.

• D.

  They were ultimately successful

35. According to paragraph 3, which of the following is true of Varicella Zoster?

• A.

  It typically attacks adults who are over 60 years old.

• B.

  It is linked to a serious disease that occurs more commonly in adults.

• C.

  It likely is not a serious enough threat to human health to require a vaccine.

• D.

  It is completely eradicated from the body after chickenpox occurs.

36. The author uses ‘booster shots’ as an example of

• A.

  A scientifically approved medicine to eliminate chickenpox

• B.

  A preferred method of chickenpox rash and fever treatment

• C.

  A way to increase the effectiveness of the chickenpox vaccine

• D.

  A strategy for parents to avoid vaccinating their child altogether

37. According to paragraph 4, many parents did not choose the chickenpox vaccine because

• A.

  They believed that the virus was weak and not especially harmful

• B.

  They thought that scientists did not have enough data to reach a conclusion

• C.

  They were unsure about the utility of the vaccine given its expected duration

• D.

  They were convinced it was potentially very toxic, particularly for older children

38. According to paragraph 5, which of the following was true of the rates of chickenpox before the chickenpox vaccine became widely used?

• A.

  It was 10 times higher

• B.

  It was consistently rising

• C.

  It declined over time

• D.

  It fluctuated over several decades

39. The word ‘prevalent’ in the passage is closest in meaning to

• A.

  Dangerous

• B.

  Widespread

• C.

  Infectious

• D.

  Contaminated

40. Look at the four squares [▪] that indicate where the following sentence could be added to the passage. "Meanwhile, some continue to remain unconvinced, citing a supposed potential of the vaccine to do harm." Where would the sentence fit best?

• A.

  A

• B.

  B

• C.

  C

• D.

  D