PSAT Critical Reading : Context-Dependent Meaning of Phrases or Sentences in Natural Science Passages

Study concepts, example questions & explanations for PSAT Critical Reading

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Example Question #31 :Natural Science Passages

Adapted fromIce-Caves of France and Switzerlandby George Forrest Browne (1865)

This account states that the cave is in the county of Thorn, among the lowest spurs of the Carpathians. The entrance, which faces the north, and is exposed to the cold winds from the snowy part of the Carpathian range, is eighteen fathoms high and nine broad; and the cave spreads out laterally, and descends to a point fifty fathoms below the entrance, where it is twenty-six fathoms in breadth, and of irregular height. Beyond this no one had at that time penetrated, on account of the unsafe footing, although many distant echoes were returned by the farther recesses of the cave; indeed, to get even so far as this, much step-cutting was necessary.

当冬天来了的外部霜,account proceeds, the effect in the cave is the same as if fires had been lighted there: the ice melts, and swarms of flies and bats and hares take refuge in the interior from the severity of the winter. As soon as spring arrives, the warmth of winter disappears from the interior, water exudes from the roof and is converted into ice, while the more abundant supplies which pour down on to the sandy floor are speedily frozen there. In the dog-days, the frost is so intense that a small icicle becomes in one day a huge mass of ice; but a cool day promptly brings a thaw, and the cave is looked upon as a barometer, not merely feeling, but also presaging, the changes of weather. The people of the neighborhood, when employed in field-work, arrange their labour so that the mid-day meal may be taken near the cave, when they either ice the water they have brought with them, or drink the melted ice, which they consider very good for the stomach.It had been calculated that six hundred weekly carts would not be sufficient to keep the cavern free from ice.The ground above the cave is peculiarly rich in grass.

在解释这些现象,贝尔扔出去the following suggestions, which need no comment. The earth being of itself cold and damp, the external heat of the atmosphere, by partially penetrating into the ground, drives in this native cold to the inner parts of the earth, and makes the cold there more dense. On the other hand, when the external air is cold, it draws forth towards the surface the heat there may be in the inner part of the earth, and thus makes caverns warm. In support and illustration of this view, he states that in the hotter parts of Hungary, when the people wish to cool their wine, they dig a hole two feet deep, and place in it the flagon of wine, and, after filling up the hole again, light a blazing fire upon the surface, which cools the wine as if the flagon had been laid in ice. He also suggests that possibly the cold winds from the Carpathians bring with them imperceptible particles of snow, which reach the water of the cave, and convert it into ice. Further, the rocks of the Carpathians abound in salts, niter, alum, etc., which may, perhaps, mingle with such snowy particles, and produce the ordinary effect of the snow and salt in the artificial production of ice.

What is the main idea of the underlined sentence in the second paragraph?

Possible Answers:

Five hundred cartloads of ice removed from the cave per week would not free the cavern from it.

The depletion of ice in the cave is induced by the movement of transportation near the cave on a weekly basis.

If carts removed ice from the cave the area nearby would grow more grass.

It is estimated that six hundred carts could clear the cave of ice in a week.

The locals could drink a vast quantity of the melted ice before the cave was depleted of it.

Correct answer:

Five hundred cartloads of ice removed from the cave per week would not free the cavern from it.

Explanation:

The next-to-last sentence in the second paragraph states that not even six hundred carts a week could clear the cave of ice. The answer that best expresses this is the one that states that “over five hundred carts of ice could not free the cavern from ice” in like terms. If six hundred cartloads of ice would not clear the cave, five hundred cartloads would not be able to either.

Example Question #41 :Passage Based Questions

Adapted fromThe Effects of Cross & Self-Fertilisation in the Vegetable Kingdomby Charles Darwin (1876)

As it is impossible to exclude such minute pollen-carrying insects as Thrips, flowers which it was intended to fertilise with their own pollen may sometimes have been afterwards crossed with pollen brought by these insects from another flower on the same plant; but as we shall hereafter see, a cross of this kind does not produce any effect, or at most only a slight one. When two or more plants were placed near one another under the same net, as was often done, there is some real though not great danger of the flowers which were believed to be self-fertilised being afterwards crossed with pollen brought by Thrips from a distinct plant. I have said that the danger is not great because I have often found that plants which are self-sterile, unless aided by insects, remained sterile when several plants of the same species were placed under the same net. If, however, the flowers which had been presumably self-fertilised by me were in any case afterwards crossed by Thrips with pollen brought from a distinct plant, crossed seedlings would have been included amongst the self-fertilised; but it should be especially observed that this occurrence would tend to diminish and not to increase any superiority in average height, fertility, etc., of the crossed over the self-fertilised plants.

As the flowers which were crossed were never castrated, it is probable or even almost certain that I sometimes failed to cross-fertilise them effectually, and that they were afterwards spontaneously self-fertilised. This would have been most likely to occur with dichogamous species, for without much care it is not easy to perceive whether their stigmas are ready to be fertilised when the anthers open. But in all cases, as the flowers were protected from wind, rain, and the access of insects, any pollen placed by me on the stigmatic surface whilst it was immature, would generally have remained there until the stigma was mature; and the flowers would then have been crossed as was intended. Nevertheless, it is highly probable that self-fertilised seedlings have sometimes by this means got included amongst the crossed seedlings. The effect would be, as in the former case, not to exaggerate but to diminish any average superiority of the crossed over the self-fertilised plants.

Errors arising from the two causes just named, and from others,—such as some of the seeds not having been thoroughly ripened, though care was taken to avoid this error—the sickness or unperceived injury of any of the plants,—will have been to a large extent eliminated, in those cases in which many crossed and self-fertilised plants were measured and an average struck. Some of these causes of error will also have been eliminated by the seeds having been allowed to germinate on bare damp sand, and being planted in pairs; for it is not likely that ill-matured and well-matured, or diseased and healthy seeds, would germinate at exactly the same time. The same result will have been gained in the several cases in which only a few of the tallest, finest, and healthiest plants on each side of the pots were measured.

Kolreuter and Gartner have proved that with some plants several, even as many as from fifty to sixty, pollen-grains are necessary for the fertilisation of all the ovules in the ovarium. Naudin also found in the case ofMirabilisthat if only one or two of its very large pollen-grains were placed on the stigma, the plants raised from such seeds were dwarfed. I was therefore careful to give an amply sufficient supply of pollen, and generally covered the stigma with it; but I did not take any special pains to place exactly the same amount on the stigmas of the self-fertilised and crossed flowers. After having acted in this manner during two seasons, I remembered that Gartner thought, though without any direct evidence, that an excess of pollen was perhaps injurious. It was therefore necessary to ascertain whether the fertility of the flowers was affected by applying a rather small and an extremely large quantity of pollen to the stigma. Accordingly a very small mass of pollen-grains was placed on one side of the large stigma in sixty-four flowers ofIpomoea purpurea, and a great mass of pollen over the whole surface of the stigma in sixty-four other flowers. In order to vary the experiment, half the flowers of both lots were on plants produced from self-fertilised seeds, and the other half on plants from crossed seeds. The sixty-four flowers with an excess of pollen yielded sixty-one capsules; and excluding four capsules, each of which contained only a single poor seed, the remainder contained on an average 5.07 seeds per capsule. The sixty-four flowers with only a little pollen placed on one side of the stigma yielded sixty-three capsules, and excluding one from the same cause as before, the remainder contained on an average 5.129 seeds. So that the flowers fertilised with little pollen yielded rather more capsules and seeds than did those fertilised with an excess; but the difference is too slight to be of any significance. On the other hand, the seeds produced by the flowers with an excess of pollen were a little heavier of the two; for 170 of them weighed 79.67 grains, whilst 170 seeds from the flowers with very little pollen weighed 79.20 grains. Both lots of seeds having been placed on damp sand presented no difference in their rate of germination. We may therefore conclude that my experiments were not affected by any slight difference in the amount of pollen used; a sufficiency having been employed in all cases.

Which of the following sentences best summarizes the start of the second paragraph?

Possible Answers:

Emasculation of the flowers was unnecessary.

The author was meticulous in both pollination and removal of stamens.

The flowers were not neutered, as there was no threat from insect pollination.

The author neglected to remove the sexual organs of the plants, leaving a possible margin for error.

If greater care had been taken, the experiments would be less anomalous.

Correct answer:

The author neglected to remove the sexual organs of the plants, leaving a possible margin for error.

Explanation:

In the first two sentences of the second paragraph, the author states that as he did not "castrate" the flowers, orremove their sexual organs, the possibility that poorly-fertilized flowers self-fertilized is possible. This would of course lead to some errors in the experiment.

Example Question #1 :Determining Context Dependent Meanings Of Phrases And Clauses In Natural Science Passages

Adapted fromA Practical Treatise on the Hive and Honey-Beeby Lorenzo Lorraine Langstroth (1857 ed.)

彼此之间的所有的无数敌人Bee-Moth (Tinea mellonella),在炎热的夏季气候,是迄今为止最to be dreaded. So widespread and fatal have been its ravages in this country that thousands have abandoned the cultivation of bees in despair, and in districts which once produced abundant supplies of the purest honey, bee-keeping has gradually dwindled down into a very insignificant pursuit. Contrivances almost without number have been devised to defend the bees against this invidious foe, but still it continues its desolating inroads, almost unchecked, laughing as it were to scorn at all the so-called "moth-proof" hives, and turning many of the ingenious fixtures designed to entrap or exclude it into actual aids and comforts in its nefarious designs.

I should feel but little confidence in being able to reinstate bee-keeping in our country into a certain and profitable pursuit if I could not show the apiarian in what way he can safely bid defiance to the pestiferous assaults of this, his most implacable enemy. I have patiently studied its habits for years, and I am at length able to announce a system of management founded upon the peculiar construction of my hives, which will enable the careful bee-keeper to protect his colonies against the monster.The bee-moth infects our apiaries, just as weeds take possession of a fertile soil.Before explaining the means upon which I rely to circumvent the moth, I will first give a brief description of its habits.

Swammerdam, towards the close of the seventeenth century, gave a very accurate description of this insect, which was then called by the very expressive name of the "bee-wolf." He has furnished good drawings of it, in all its changes, from the worm to the perfect moth, together with the peculiar webs or galleries that it constructs and from which the name ofTinea galleriaor “gallery moth” has been given to it by some entomologists. He failed, however, to discriminate between the male and female, which, because they differ so much in size and appearance, he supposed to be two different species of the wax-moth. It seems to have been a great pest in his time, and even Virgil speaks of the "dirum tineæ genus," the dreadful offspring of the moth; that is the worm.

This destroyer usually makes its appearance about the hives in April or May, the time of its coming depending upon the warmth of the climate or the forwardness of the season. It is seldom seen on the wing (unless startled from its lurking place about the hive) until towards dark, and is evidently chiefly nocturnal in its habits. In dark cloudy days, however, I have noticed it on the wing long before sunset, and if several such days follow in succession, the female, oppressed with the urgent necessity of laying her eggs, may be seen endeavoring to gain admission to the hives. The female is much larger than the male, and "her color is deeper and more inclining to a darkish gray, with small spots or blackish streaks on the interior edge of her upper wings." The color of the male inclines more to a light gray; they might easily be mistaken for different species of moths. These insects are surprisingly agile, both on foot and on the wing. The motions of a bee are very slow in comparison. "They are," says Reaumur, "the most nimble-footed creatures that I know." "If the approach to the apiary be observed of a moonlight evening, the moths will be found flying or running round the hives, watching an opportunity to enter, whilst the bees that have to guard the entrances against their intrusion will be seen acting as vigilant sentinels, performing continual rounds near this important post, extending their antenna to the utmost, and moving them to the right and left alternately. Woe to the unfortunate moth that comes within their reach!" "It is curious," says Huber, "to observe how artfully the moth knows how to profit, to the disadvantage of the bees, which require much light for seeing objects; and the precautions taken by the latter in reconnoitering and expelling so dangerous an enemy."

Which of these most accurately restates the meaning of “The bee-moth infects our apiaries, just as weeds take possession of a fertile soil," a line found in the second paragraph?

Possible Answers:

The impact of the bee moth on a hive is disproportionate to that of the weed on a garden.

The description of the moth is not sufficient without considering its impact on a garden.

The bee moth is nothing compared to the weed in fertile soil.

None other than gardeners and bee keepers can comprehend the devastations of the moth.

The bee moth is to the bee keeper what the dandelion is to the gardener.

Correct answer:

The bee moth is to the bee keeper what the dandelion is to the gardener.

Explanation:

The author is making a comparison by using the simile of the moth being like a weed. So, the moth has a similar effect on a hive as a weed—like a dandelion—has on a garden.

Example Question #1 :特定的短语和句子在自然科学Passages

Adapted from “Darwin’s Predecessors” by J. Arthur Thomson inEvolution in Modern Thought(1917 ed.)

In seeking to discover Darwin's relation to his predecessors, it is useful to distinguish the various services which he rendered to the theory of organic evolution.

As everyone knows, the general idea of the doctrine of descent is that the plants and animals of the present day are the lineal descendants of ancestors on the whole somewhat simpler, that these again are descended from yet simpler forms, and so on backwards towards the literal "Protozoa" and "Protophyta" about which we unfortunately know nothing. Now no one supposes that Darwin originated this idea, which in rudiment at least is as old as Aristotle. What Darwin did was to make itcurrent intellectual coin. He gave it a form that commended itself to the scientific and public intelligence of the day, and he won widespread conviction by showing with consummate skill that it was an effective formula to work with, a key which no lock refused. In a scholarly, critical, and preeminently fair-minded way, admitting difficulties and removing them, foreseeing objections and forestalling them, he showed that the doctrine of descent supplied a modal interpretation of how our present-day fauna and flora have come to be.

In the second place, Darwin applied the evolution-idea to particular problems, such as the descent of man, and showed what a powerful tool it is, introducing order into masses of uncorrelated facts, interpreting enigmas both of structure and function, both bodily and mental, and, best of all, stimulating and guiding further investigation. But here again it cannot be claimed that Darwin was original. The problem of the descent or ascent of man, and other particular cases of evolution, had attracted not a few naturalists before Darwin's day, though no one [except Herbert Spencer in the psychological domain (1855)] had come near him in precision and thoroughness of inquiry.

第三,达尔文很大程度上起到了推波助澜的作用a knowledge of the factors in the evolution-process, especially by his analysis of what occurs in the case of domestic animals and cultivated plants, and by his elaboration of the theory of natural selection, which Alfred Russel Wallace independently stated at the same time, and of which there had been a few previous suggestions of a more or less vague description. It was here that Darwin's originality was greatest, for he revealed to naturalists the many different forms—often very subtle—which natural selection takes, and with the insight of a disciplined scientific imagination he realized what a mighty engine of progress it has been and is.

What is meant by the underlined expression, “current intellectual coin”?

Possible Answers:

None of the other answers

A topic with ramifications for the markets

A regular topic of discussion

A profitable topic to pursue

An example of a publishable field of inquiry

Correct answer:

A regular topic of discussion

Explanation:

The best way to approach this expression is by thinking of the expression "to coin a phrase." We say that someone "coins" a phrase when he or she invents it, using it for the first time before later becomes popular. The general idea is that the phase is able to be "traded" in discourse. We can use it when talking as if such ideas are like coins in commerce. Therefore, to make something "common intellectual coin" is to make it something that can be discussed, that is, to make it a topic of general discussion.

Example Question #62 :Science

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” inTropical Nature, and Other Essaysby Alfred Russel Wallace (1878)

The food of hummingbirds has been a matter of much controversy. All the early writers down to Buffon believed that they lived solely on the nectar of flowers, but since that time, every close observer of their habits maintains that they feed largely, and in some cases wholly, on insects. Azara observed them on the La Plata in winter taking insects out of the webs of spiders at a time and place where there were no flowers. Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs. Waterton made a similar statement. Hundreds and perhaps thousands of specimens have since been dissected by collecting naturalists, and in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey. Many of them in fact may be seen catching gnats and other small insects just like fly-catchers, sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig. Others come out just at dusk, and remainon the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose. Mr. Gosse also remarks, ” All the hummingbirds have more or less the habit, when in flight, of pausing in the air and throwing the body and tail into rapid and odd contortions. This is most observable in the Polytmus, from the effect that such motions have on the long feathers of the tail. That the object of these quick turns is the capture of insects, I am sure, having watched one thus engaged pretty close to me.”

The meaning of the underlined phrase “on the wing” is__________.

Possible Answers:

vacationing

without preparation or preplanning

having been thrown

in flight

located on a feather on a bird’s wing

Correct answer:

in flight

Explanation:

The phrase “on the wing” is used in the following sentence in the passage:

“[Other hummingbirds] come out just at dusk, and remainon the wing, now stationary, now darting about with the greatest rapidity, imitating in a limited space the evolutions of the goatsuckers, and evidently for the same end and purpose.”

“On the wing” may initially appear to mean just what it says, “located on a feather on a bird’s wing,’ but considering the way it is used in the passage, this doesn’t make any sense. The sentence describes the hummingbirds “darting about,” and in order for them to do that, they would have to be flying, so you can tell that “on the wing” means “in flight.” None of the other answer choices make sense given the context in which the phrase is used.

Example Question #31 :Language In Natural Science Passages

Adapted from “Introduced Species That Have Become Pests” inOur Vanishing Wild Life, Its Extermination and Protectionby William Temple Hornaday (1913)

The man who successfully transplants or "introduces" into a new habitat any persistent species of living thing assumes a very grave responsibility.Every introduced species is doubtful gravel until panned out.The enormous losses that have been inflicted upon the world through the perpetuation of follies with wild vertebrates and insects would, if added together, be enough to purchase a principality. The most aggravating feature of these follies in transplantation is that never yet have they been made severely punishable. We are just as careless and easygoing on this point as we were about the government of the Yellowstone Park in the days when Howell and other poachers destroyed our first national bison herd, and when caught red-handed—as Howell was, skinning seven Park bison cows—could not be punished for it, because there was no penalty prescribed by any law. Today, there is a way in which any revengeful person could inflict enormous damage on the entire South, at no cost to himself, involve those states in enormous losses and the expenditure of vast sums of money, yet go absolutely unpunished!

The gypsy moth is a case in point. This winged calamity was imported at Maiden, Massachusetts, near Boston, by a French entomologist, Mr. Leopold Trouvelot, in 1868 or 69. History records the fact that the man of science did not purposely set free the pest. He was endeavoring with live specimens to find a moth that would produce a cocoon of commercial value to America, and a sudden gust of wind blew out of his study, through an open window, his living and breeding specimens of the gypsy moth. The moth itself is not bad to look at, but its larvae is a great, overgrown brute with an appetite like a hog. Immediately Mr. Trouvelot sought to recover his specimens, and when he failed to find them all, like a man of real honor, he notified the State authorities of the accident. Every effort was made to recover all the specimens, but enough escaped to produce progeny that soon became a scourge to the trees of Massachusetts. The method of the big, nasty-looking mottled-brown caterpillar was very simple. It devoured the entire foliage of every tree that grew in its sphere of influence.

The gypsy moth spread with alarming rapidity and persistence. In course of time, the state authorities of Massachusetts were forced to begin a relentless war upon it, by poisonous sprays and by fire. It was awful! Up to this date (1912) the New England states and the United States Government service have expended in fighting this pest about $7,680,000!

The spread of this pest has been retarded, but the gypsy moth never will be wholly stamped out. Today it exists in Rhode Island, Connecticut, and New Hampshire, and it is due to reach New York at an early date. It is steadily spreading in three directions from Boston, its original point of departure, and when it strikes the State of New York, we, too, will begin to pay dearly for the Trouvelot experiment.

Which of the following best paraphrases the underlined sentence, “Every introduced species is doubtful gravel until panned out”?

Possible Answers:

One should never move a species from its natural environment into a new environment for fear of the consequences.

One can’t tell whether an introduced species will be helpful or harmful until it is actually introduced.

An invasive species can cause beneficial effects to its new environment as well as harmful ones.

Species that live in gravel are usually harmful when placed in new environments.

Species that live underground should be carefully examined before being moved into new environments.

Correct answer:

One can’t tell whether an introduced species will be helpful or harmful until it is actually introduced.

Explanation:

Here, the author is using figurative language to describe introduced species. He metaphorically calls them “doubtful gravel until [they are] panned out.” Because he’s not speaking literally, this sentence has nothing to do with the ground or gravel itself, so we can eliminate the answer choices “Species that live underground should be carefully examined before being moved into new environments” and “Species that live in gravel are usually harmful when placed in new environments.”

作者和他的比喻的意思是什么?Panning rocks and dirt allows miners to separate out valuable minerals from other matter. Think of miners “panning for gold”—it’s the same principle, except here, the author is speaking of it as applying to gravel. By calling the gravel “doubtful,” the author is expressing that you don’t know what you’re going to get with it before you “pan it out” and see if there is anything valuable in it. Applying this thinking to invasive species, the author is therefore saying that “one can’t tell whether an introduced species will be helpful or harmful until it is actually introduced.”

如果你不知道什么是平移砾石,你公司uld still solve this question by narrowing down your answer choices. For instance, nowhere in the passage are the beneficial effects of introduced species discussed, though the author discusses this in a previous chapter of his book. Because they’re not mentioned in the passage, we can discard the answer choice “An invasive species can cause beneficial effects to its new environment as well as harmful ones.” This is definitely not what the indicated sentence is saying; if we replaced the sentence with this answer choice, the logic of the paragraph wouldn’t make any sense.

至于剩下的答案的选择,“每个人都应该不ver move a species from its natural environment into a new environment for fear of the consequences,” it cannot be correct because in the sentence before the one on which this question focuses, the author writes, “The man who successfully transplants or ‘introduces' into a new habitat any persistent species of living thing assumes a very grave responsibility.” Note that he doesn’t say that this should never be done; he just implies that it could go very badly. It wouldn’t make much sense if in the next sentence, the author said this should never be done. It seems more logical that he would have led with that statement, it being the stronger of the two.

Example Question #11 :Context Dependent Meaning Of Phrases Or Sentences In Natural Science Passages

"The Place of Lesion Studies in Neuroscience" by Samantha Winter (2013)

It’s easy to forget that the study of neuroscience originated from non-normalized, non-statistically appraised methods like lesion studies. It’s equally easy, with the advent of sophisticated technology,to render such a method obsolete. A small group of neuroscientists today make a case for the reinstitution of lesion studies—the study of abnormal brains with damaged regions in order to better understand the brain—into the twenty-first-century cognitive neuroscience realm. Their suggestion is bold, but their argument is justified.

Cognitive neuroscientists advocate for the use of convergent methods. Many of them argue that with the limitations of our existing techniques, convergent evidence is imperative for sound research. If this is the case, why ignore a method that has potential for implying causality in a domain dominated by correlational research? Rather than advocating for a single method, neuroscientists should take their own advice and use convergent techniques. Sound research should combine a variety of techniques to examine both causal relationships and overcome the individual shortcomings of each method through the use of many.

Lesion studies are also significantly more beneficial now than they were in earlier times. Neuroimaging methods have enhanced our understanding of what contributes to the brain problems most often encountered, and more refined experiments have been developed to confirm the findings from the more unreliable lesion studies. This transformation allows lesion studies to be included alongside the other systems as a mechanism for understanding the human brain.

The underlined selection "to render such a method obsolete" most closely means__________.

Possible Answers:

to question the existence of lesion studies

to make neuroscience the most important field of science

to consider lesion studies outdated

to make lesion studies more important

to redesign lesion studies

Correct answer:

to consider lesion studies outdated

Explanation:

The answer isobsolete, because it means outdated or archaic, and the word “method” refers back to the prior sentence, “methods like lesion studies,” thus stating that the some consider these lesion studies outdated. Because of the meaning of the word obsolete, "to make lesion studies more important" is incorrect. This statement does not refer to the field of neuroscience, therefore "to make neuroscience the most important field of science" is incorrect, and there is no consideration in the paper (and certainly not in the first few sentences) that lesions do not exist, just how valuable they are to the field of study – therefore "to question the existence of lesion studies" is incorrect.

Example Question #1 :Context Dependent Meaning Of Phrases Or Sentences In Natural Science Passages

Adapted from Volume Four ofThe Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relationsby James Richard Ainsworth Davis (1903)

The examples of protective resemblance so far quoted are mostly permanent adaptations to one particular sort of surrounding. There are, however, numerous animals which possess the power of adjusting their color more or less rapidly so as toharmonize witha changing environment.

Some of the best known of these cases are found among those mammals and birds that inhabit countries more or less covered with snow during a part of the year. A good instance is afforded by the Irish or variable hare, which is chiefly found in Ireland and Scotland. In summer, this looks very much like an ordinary hare, though rather grayer in tint and smaller in size, but in winter it becomes white with the exception of the black tips to the ears. Investigations that have been made on the closely allied American hare seem to show that the phenomenon is due to the growth of new hairs of white hue.

The common stoat is subject to similar color change in the northern parts of its range. In summer it is of a bright reddish brown color with the exception of the under parts, which are yellowish white, and the end of the tail, which is black. But in winter, the entire coat, save only the tip of the tail, becomes white, and in that condition the animal is known as an ermine. A similar example is afforded by the weasel. The seasonal change in the vegetarian Irish hare is purely of protective character, but in such an actively carnivorous creature as a stoat or weasel, it is aggressive as well, rendering the animal inconspicuous to its prey.

The phrase “harmonize with,” underlined in the first paragraph, most closely means__________.

Possible Answers:

conduct

sing in harmony with

systematize

match

parallel

Correct answer:

match

Explanation:

The phrase “harmonize with” appears in this sentence in the first paragraph: “There are, however, numerous animals which possess the power of adjusting their color more or less rapidly so as toharmonize witha changing environment.” While “harmonize with” can mean “sing in harmony with,” this meaning doesn’t make sense in the context of the passage’s sentence. “Parallel,” “systematize,” and “conduct” don’t make sense either—only “match” makes sense, so it is the correct answer.

Example Question #2 :Context Dependent Meaning Of Phrases Or Sentences In Natural Science Passages

Adapted from “Feathers of Sea Birds and Wild Fowl for Bedding” fromThe Utility of Birdsby Edward Forbush (ed. 1922)

In the colder countries of the world, the feathers and down of waterfowl have been in great demand for centuries as filling for beds and pillows. Such feathers are perfect non-conductors of heat, and beds, pillows, or coverlets filled with them represent the acme of comfort and durability. The early settlers of New England saved for such purposes the feathers and down from the thousands of wild-fowl which they killed, butas the population increased in numbers, the quantity thus furnished was insufficient, and the people sought a larger supply in the vast colonies of ducks and geese along the Labrador coast.

The manner in which the feathers and down were obtained, unlike the method practiced in Iceland, did not tend to conserve and protect the source of supply. In Iceland, the people have continued to receive for many years a considerable income by collecting eider down, but there they do not “kill the goose that lays the golden eggs.” Ducks line their nests with down plucked from their own breasts and that of the eider is particularly valuable for bedding. In Iceland, these birds are so carefully protected that they have become as tame and unsuspicious as domestic fowls In North America. Where they are constantly hunted they often conceal their nests in the midst of weeds or bushes, but in Iceland, they make their nests and deposit their eggs in holes dug for them in the sod. A supply of the ducks is maintained so that the people derive from them an annual income.

In North America, quite a different policy was pursued. The demand for feathers became so great in the New England colonies about the middle of the eighteenth century that vessels were fitted out there for the coast of Labrador for the express purpose of securing the feathers and down of wild fowl. Eider down having become valuable and these ducks being in the habit of congregating by thousands on barren islands of the Labrador coast, the birds became the victims of the ships’ crews. As the ducks molt all their primary feathers at once in July or August and are then quite incapable of flight and the young birds are unable to fly until well grown, the hunters were able to surround the helpless birds, drive them together, and kill them with clubs. Otis says that millions of wildfowl were thus destroyed and that in a few years their haunts were so broken up by this wholesale slaughter and their numbers were so diminished that feather voyages became unprofitable and were given up.

This practice, followed by the almost continual egging, clubbing, shooting, etc. by Labrador fishermen, may have been a chief factor in the extinction of the Labrador duck, that species of supposed restricted breeding range. No doubt had the eider duck been restricted in its breeding range to the islands of Labrador, it also would have been exterminated long ago.

Which of the following best restates the meaning of the underlined phrase “as the population increased in numbers, the quantity thus furnished was insufficient”?

Possible Answers:

As the number of ducks increased, the number of eggs they laid became no longer satisfactory

As the number of citizens of New England increased, the desirability of eider down decreased

As the population of New England settlers increased, the amount of eider down collected was no longer enough

As the population of Icelandic ducks increased, their food sources began to deplete

As the number of Icelandic citizens increased, the populations of Icelandic ducks decreased

Correct answer:

As the population of New England settlers increased, the amount of eider down collected was no longer enough

Explanation:

In order to answer this question correctly, you have to consider the context in which this phrase appears: “The early settlers of New England saved for such purposes the feathers and down from the thousands of wild-fowl which they killed, but as the population increased in numbers, the quantity thus furnished was insufficient, and the people sought a larger supply in the vast colonies of ducks and geese along the Labrador coast.” It only makes sense for “population” to refer to a population of people, not of ducks, as the sentence concludes by saying “the people sought a larger supply in the vast colonies of ducks and geese along the Labrador coast.” They would not need to seek out a larger supply of ducks and geese if the population of ducks and geese was increasing. Knowing this, we can discard the answer choices “As the number of ducks increased, the number of eggs they laid became no longer satisfactory” and “As the population of Icelandic ducks increased, their food sources began to deplete.” The sentence is only discussing New England settlers; it does not mention Iceland. So, “As the number of Icelandic citizens increased, the populations of Icelandic ducks decreased” cannot be correct either. This leaves us with two answer choices: “As the number of citizens of New England increased, the desirability of eider down decreased,” and “As the population of North America increased, the amount of eider down collected was no longer enough.” The important distinction made between these two answer choices hinges on the meaning of the word “quantity.” “Quantity” meansnumber of, so the correct answer is “As the population of New England increased, the amount of eider down collected was no longer enough.” If you read the sentence quickly and confused quantity with “quality,” which meanshow good something is, you may have picked the other answer choice. It’s important to read carefully, especially when answering questions that deal with paraphrasing!

Example Question #1 :分析科学中的文本段落

Adapted from "Recent Views as to Direct Action of Light on the Colors of Flowers and Fruits" inTropical Nature, and Other Essaysby Alfred Russel Wallace (1878)

The theory that the brilliant colors of flowers and fruits is due to the direct action of light has been supported by a recent writer by examples taken from the arctic instead of from the tropical flora. In the arctic regions, vegetation is excessively rapid during the short summer, and this is held to be due to the continuous action of light throughout the long summer days. "The further we advance towards the north, the more the leaves of plants increase in size as if to absorb a greater proportion of the solar rays.M. Grisebach says that during a journey in Norway he observed that the majority of deciduous trees had already, at the 60th degree of latitude, larger leaves than in Germany, while M. Ch. Martins has made a similar observation as regards the leguminous plants cultivated in Lapland.” The same writer goes on to say that all the seeds of cultivated plants acquire a deeper color the further north they are grown, white haricots becoming brown or black, and white wheat becoming brown, while the green color of all vegetation becomes more intense. The flowers also are similarly changed: those which are white or yellow in central Europe becoming red or orange in Norway. This is what occurs in the Alpine flora, and the cause is said to be the same in both—the greater intensity of the sunlight. In the one the light is more persistent, in the other more intense because it traverses a less thickness of atmosphere.

Admitting the facts as above stated to be in themselves correct, they do not by any means establish the theory founded on them; and it is curious that Grisebach, who has been quoted by this writer for the fact of the increased size of the foliage, gives a totally different explanation of the more vivid colors of Arctic flowers. He says, “We see flowers become larger and more richly colored in proportion as, by the increasing length of winter, insects become rarer, and their cooperation in the act of fecundation is exposed to more uncertain chances.” (Vegetation du Globe, col. i. p. 61—French translation.) This is the theory here adopted to explain the colors of Alpine plants, and we believe there are many facts that will show it to be the preferable one. The statement that the white and yellow flowers of temperate Europe become red or golden in the Arctic regions must we think be incorrect. By roughly tabulating the colors of the plants given by Sir Joseph Hooker as permanently Arctic, we find among fifty species with more or less conspicuous flowers, twenty-five white, twelve yellow, eight purple or blue, three lilac, and two red or pink; showing a very similar proportion of white and yellow flowers to what obtains further south.

The underlined sentence in the passage tells us that__________.

Possible Answers:

树叶在树上的数量与latitude in which it is found

the further south you travel, the smaller plants’ leaves should be

leaf size is associated with atmospheric moisture levels

如果你把a plant from a northern climate into a southern climate, its leaves will shrink

many northern-dwelling plants have small leaves

Correct answer:

the further south you travel, the smaller plants’ leaves should be

Explanation:

The underlined sentence is "The further we advance towards the north, the more the leaves of plants increase in size as if to absorb a greater proportion of the solar rays." This has nothing to do with the number of leaves on a plant, so "the number of leaves on a tree is related to the latitude in which it is found" cannot be the correct answer. Similarly, nothing is said about moisture levels in the specified sentence, so "leaf size is associated with atmospheric moisture levels" cannot be correct either. Many northern-dwelling plants have small leaves" reverses the relationship being presented in a way that makes it incorrect; northern plants should have large leaves, not small ones. "If you take a plant from a northern climate into a southern climate, its leaves will shrink" derives too much from the statement; nothing is said about a given set of leaves changing size, just a variation amongst the sizes of many different sets of leaves. This leaves us with one remaining answer choice, the correct one: "the further south you travel, the smaller plants’ leaves should be." The specified sentence tells us that if you move north, the leaves of plants you see should get bigger. So, therefore, if you head south, the leaves you see on plants should get smaller. The correct answer states what the sentence is saying in a reverse, but still correct, way.

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