16. The seventeenth-century physicist Sir Isaac Newton is remembered chiefly for his treaties on motion and gravity. But Newton also conducted experiments secretly for many years based on the arcane theories of alchemy, trying unsuccessfully to transmute common metals into gold and produce rejuvenating elixirs. If the alchemists of the seventeenth century had published the results of their experiments, chemistry in the eighteenth century would have been more advanced than it actually was.
Which one of the following assumptions would allow the conclusion concerning eighteenth-century chemistry to be properly drawn?
(A) Scientific progress is retarded by the reluctance of historians to acknowledge the failures of some of the great scientists.
(B) Advances in science are hastened when reports of experiments, whether successful or not, are available for review by other scientists.
(C) Newton’s work on motion and gravity would not have gained wide acceptance if the results of his work in alchemy had also been make public.
(D) Increasing specialization within the sciences makes it difficult for scientists in one field to understand the principles of other fields.
(E) The seventeenth-century alchemists could have achieved their goals only if their experiments had been subjected to public scrutiny.
17. Sedimentary rock hardens within the earth’s crust as layers of matter accumulate and the pressure of the layers above converts the layers below into rock. One particular layer of sedimentary rock that contains an unusual amount of the element iridium has been presented as support for a theory that a meteorite collided with the earth some sixty million years ago. Meteorites are rich in iridium compared to the earth’s crust, and geologists theorize that a meteorite’s collision with the earth raised a huge cloud of iridium-laden dust. The dust, they say, eventually settled to earth where it combined with other matter, and as new layers accumulated above it, it formed a layer of iridium-rich rock.
Which one of the following, if true, would counter the claim that the iridium-rich layer described in the passage is evidence for the meteorite collision theory?
(A) The huge dust cloud described in the passage would have blocked the transmission of sunlight and lowered the earth’s temperature.
(B) A layer of sedimentary rock takes millions of years to harden.
(C) Layers of sedimentary rock are used to determine the dates of prehistoric events whether or not they contain iridium.
(D) Sixty million years ago there was a surge in volcanic activity in which the matter spewed from the volcanoes formed huge iridium-rich dust clouds.
(E) The iridium deposit occurred at about the same time that many animal species became extinct and some scientists have theorized that mass dinosaur extinctions were caused by a meteorite collision.
18. Mary, a veterinary student, has been assigned an experiment in mammalian physiology that would require her to take a healthy, anesthetized dog and subject it to a drastic blood loss in order to observe the physiological consequences of shock. The dog would neither regain consciousness nor survive the experiment. Mary decides not to do this assignment.
Mary’s decision most closely accords with which one of the following principles?
(A) All other things being equal, gratuitously causing any animal to suffer pain is unjustified.
(B) Taking the life of an animal is not justifiable unless doing so would immediately assist in saving several animal lives or in protecting the health of a person.
(C) The only sufficient justification for experimenting on animals is that future animal suffering is thereby prevented.
(D) Practicing veterinarians have a professional obligation to strive to prevent the unnecessary death of an animal except in cases of severely ill or injured animals whose prospects for recovery are dim.
(E) No one is ever justified in acting with the sole intention of causing the death of a living thing, be it animal or human.
19. A tree’s age can be determined by counting the annual growth rings in its trunk. Each ring represents one year, and the ring’s thickness reveals the relative amount of rainfall that year. Archaeologists successfully used annual rings to determine the relative ages of ancient tombs at Pazyryk. Each tomb was constructed from freshly cut logs, and the tombs builders were constrained by tradition to use only logs from trees growing in the sacred Pazyryk Valley.
Which one of the following, if true, contributes most to an explanation of the archaeologists’ success in using annual rings to establish the relative ages of the tombs at the Pazyryk site?
(A) The Pazyryk tombs were all robbed during ancient times, but breakage of the tombs seals allowed the seepage of water, which soon froze permanently, thereby preserving the tombs’ remaining artifacts.
(B) The Pazyryk Valley, surrounded by extremely high mountains, has a distinctive yearly pattern of rainfall, and so trees growing in the Pazyryk Valley have annual rings that are quite distinct from trees growing in nearby valleys.
(C) Each log in the Pazyryk tombs has among its rings a distinctive sequence of twelve annual rings representing six drought years followed by three rainy years and three more drought years.
(D) The archaeologists determined that the youngest tree used in any of the tombs was 90 years old and that the oldest tree was 450 years old.
(E) All of the Pazyryk tombs contained cultural artifacts that can be dated to roughly 2300 years ago.
20. Experienced gardeners advise against planting snap peas after late April because peas do not develop properly in warm weather. This year, however, the weather was unusually cool into late June, and therefore the fact that these snap peas were planted in mid-May is unlikely to result in crop failure despite the experts’ warnings.
The pattern of reasoning displayed above is most closely paralleled in which one of the following?
(A) According to many gardening authorities, tomatoes should not be planted near dill because doing so is likely to affect their taste adversely; however, since these tomatoes were grown near dill and taste fine, there is clearly no reason to pay much attention to the so-called experts’ advice.
(B) Since African violets do not thrive in direct sunlight, it is said that in this region these plants should be placed in windows facing north rather than south; however, since these south-facing windows are well shaded by evergreen trees, the African violets placed in them are likely to grow satisfactorily.
(C) Where flowers are to be planted under shade trees, gardening experts often advise using impatiens since impatiens does well in conditions of shade; however, it is unlikely to do well under maple trees since maple tree roots are so near the surface that they absorb all available moisture.
(D) Most seeds tend to germinate at much higher rates when planted in warm soil than when planted in cold soil; spinach seeds, however, are unlikely to germinate properly if the soil is too warm, and therefore experts advise that spinach should be planted earlier than most vegetables.
(E) House plants generally grow best in pots slightly larger than their existing root systems, so the usual advice is to repot when roots first reach the sides of the pot; this rule should no be followed with amaryllis plants, however, because they are likely to do best with tightly compressed roots.