Adapted from “In Mammoth Cave” by John Burroughs (1894)

Some idea of the impression which Mammoth Cave makes upon the senses, irrespective even of sight, may be had from the fact that blind people go there to see it, and are greatly struck with it. I was assured that this is a fact. The blind seem as much impressed by it as those who have their sight. When the guide pauses at a more interesting point, or lights the scene up with a great torch or with small flares, and points out the more striking features, the blind exclaim, "How wonderful! How beautiful!" They can feel it, if they cannot see it. They get some idea of the spaciousness when words are uttered. The voice goes forth in these colossal chambers like a bird. When no word is spoken, the silence is of a kind never experienced on the surface of the earth, it is so profound and abysmal. This, and the absolute darkness, to a sighted person makes him feel as if he were face to face with the primordial nothingness. The objective universe is gone; only the subjective remains; the sense of hearing is inverted, and reports only the murmurs from within. The blind miss much, but much remains to them. The great cave is not merely a spectacle to the eye; it is a wonder to the ear, a strangeness to the smell and to the touch. The body feels the presence of unusual conditions through every pore.

The primary purpose of this passage is to __________.

Adapted from Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by 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 to harmonize with a 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 purpose of the passage’s third paragraph is __________.

Adapted from Volume Four of The Natural History of Animals: The Animal Life of the World in Its Various Aspects and Relations by 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 to harmonize with a 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.

In which of the following would you most expect to find this passage reprinted?

Adapted from Cassell’s Natural History by Francis Martin Duncan (1913)

The penguins are a group of birds inhabiting the southern ocean, for the most part passing their lives in the icy waters of the Antarctic seas. Like the ratitae, penguins have lost the power of flight, but the wings are modified into swimming organs and the birds lead an aquatic existence and are scarcely seen on land except in the breeding season. They are curious-looking creatures that appear to have no legs, as the limbs are encased in the skin of the body and the large flat feet are set so far back that the birds waddle along on land in an upright position in a very ridiculous manner, carrying their long narrow flippers held out as if they were arms. When swimming, penguins use their wings as paddles while the feet are used for steering.

Penguins are usually gregarious—in the sea, they swim together in schools, and on land, assemble in great numbers in their rookeries. They are very methodical in their ways, and on leaving the water, the birds always follow well-defined tracks leading to the rookeries, marching with much solemnity one behind the other in soldierly order. 

The largest species of penguins are the king penguin and the emperor penguin, the former being found in Kerguelen Land, the Falklands, and other southern islands, and the latter in Victoria Land and on the pack ice of the Antarctic seas. As they are unaccustomed from the isolation of their haunts to being hunted and persecuted by man, emperor penguins are remarkably fearless, and Antarctic explorers invading their territory have found themselves objects of curiosity rather than fear to the strange birds who followed them about as if they were much astonished at their appearance. 

The emperor penguin lays but a single egg and breeds during the intense cold and darkness of the Antarctic winter. To prevent contact with the frozen snow, the bird places its egg upon its flat webbed feet and crouches down upon it so that it is well covered with the feathers. In spite of this precaution, many eggs do not hatch and the mortality amongst the young chicks is very great.

Where would you most expect to find this passage?

Adapted from “Feathers of Sea Birds and Wild Fowl for Bedding” from The Utility of Birds by 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, 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. 

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.

In the context of the passage as a whole, the fourth paragraph serves to __________.

Adapted from The Story of Eclipses by George F. Chambers (1900)

Observations of total solar eclipses during the nineteenth century have been, for the most part, carried out under circumstances so essentially different from everything that has gone before, that not only does a new chapter seem desirable but also a new form of treatment. Up to the beginning of the eighteenth century, the observations (even the best of them) may be said to have been made and recorded with but few exceptions by unskilled observers with no clear ideas as to what they should look for and what they might expect to see. Things improved a little during the eighteenth century, and the observations by Halley, Maclaurin, Bradley, Don Antonio Ulloa, Sir W. Herschel, and others in particular rose to a much higher standard than any that had preceded them. However, it has only been during the nineteenth century, and especially during the latter half of it, that total eclipses of the sun have been observed under circumstances calculated to extract from them large and solid extensions of scientific knowledge.

The total eclipse of July 28, 1851, may be said to have been the first which was the subject of an “Eclipse Expedition,” a phrase which of late years has become exceedingly familiar. The total phase was visible in Norway and Sweden, and great numbers of astronomers from all parts of Europe flocked to those countries. The red flames were very much in evidence, and the fact that they belonged to the sun and not to the moon was clearly established. Hind mentions that “the aspect of Nature during the total eclipse was grand beyond description.” This feature is dwelt upon with more than usual emphasis in many of the published accounts. I have never seen it suggested that the mountainous character of the country may have had something to do with it, but that idea would seem not improbable.

In the year 1858, two central eclipses of the sun occurred, both presenting some features of interest. That of March 15 was annular, the central line passing across England. The weather generally was unfavorable and the annular phase was only observed at a few places, but important meteorological observations were made and yielded results, as regards the diminution of temperature, which were very definite.

The main point of the first paragraph is __________.

Adapted from Anecdotes of the Habits and Instincts of Animals by Mrs. R. Lee (1852)

There are instances of weasels having been tamed, but it is very difficult to make any impression on their affections, although they are very sagacious, and sagacious animals are more easily influenced than others. The weasel and the stoat are so often mistaken for each other that it will be well to point out the constant difference in each. The stoat is brown above, dirty white underneath; its tail is longer and more bushy than that of the weasel, and always black at the tip. The weasel is red above, and pure white underneath, and the tail is red and uniform, being deprived of the bushy tip.

Mr. Bell, from whose pages I have taken these characters, states that weasels should not be accused of devouring poultry, game, hares, rabbits, and various small birds. He says that when driven by hunger, they may occasionally eat such things; but that their general food consists of mice and rats of every description, the field and water vole, and moles, and that they ought rather to be encouraged than exterminated, because they destroy so much vermin. They generally approach with the utmost caution and shyness, and when once they have seized their prey, they never let go their hold; they aim at the neck, below the ear, or drive their teeth through the back of the head. They hound and spring, and climb trees with the greatest facility, and seem never to tire of hunting, whether they are hungry or not.

Proof of the weasel's affection for her young was witnessed by a laborer, who, while standing on a foot-path close to the hedge side, perceived a weasel with one of her young ones in her mouth. He kicked her, and she, dropping it, retreated into a hedge. He then stood over the young one with a stick in his hand, not intending to kill it, but merely to see how its mother would proceed. She soon peeped from her cover, and made several feints to get at her charge, but was obliged to run into the hedge again, intimidated by the stick which the man flourished about. At last she summoned up all her resolution, and in spite of everything, after a great deal of dodging to avoid the stick, succeeded in obtaining the object of her solicitude, and bore it off between the legs of her tormentor.

The final paragraph is concerned with __________.

Adapted from The Story of Eclipses by George F. Chambers (1900)

The primary meaning of the word “eclipse” is a forsaking, quitting, or disappearance. Hence the covering over of something by something else, or the immersion of something in something; and these apparently crude definitions will be found on investigation to represent precisely the facts of the case.

Inasmuch as the Earth and the Moon are for our present purpose practically “solid bodies,” each must cast a shadow into space as the result of being illuminated by the sun, regarded as a source of light.

The various bodies which together make up the solar system, that is to say, in particular, those bodies called the “planets”—some of them “primary,” others “secondary” (alias “satellites” or “moons”)—are constantly in motion. Consequently, if we imagine a line to be drawn between any two at any given time, such a line will point in a different direction at another time, and so it may occasionally happen that three of these ever-moving bodies will come into one and the same straight line. Now the consequences of this state of things were admirably well pointed out nearly half a century ago by a popular writer, who in his day greatly aided the development of science amongst the masses. “When the sun is the furthest away of three solar bodies which are all facing the same direction, the intermediate body deprives the other extreme body, either wholly or partially, of the illumination which it usually receives. When one of the extremes is the Earth, the intermediate body intercepts, wholly or partially, the other extreme body from the view of the observers situated at places on the Earth which are in the common line of direction, and the intermediate body is seen to pass over the other extreme body as it enters upon or leaves the common line of direction. The phenomena resulting from such contingencies of position and direction are variously called eclipses, transits, and occultations, according to the relative apparent magnitudes of the interposing and obscured bodies, and according to the circumstances which attend them.”

Which of the following best describes the author's intention in including the quotation from the "popular writer"?

Adapted from "The Wild Llama" by Charles Darwin in A Book of Natural History (1902, ed. David Starr Jordan)

The wild llama is the characteristic quadruped of the plains of Patagonia; it is the South American representative of the camel in the East. It is an elegant animal in a state of nature, with a long slender neck and fine legs. It is very common over the whole of the temperate parts of the continent, as far south as the islands near Cape Horn. It generally lives in small herds of from half a dozen to thirty in each, but on the banks of the St. Cruz we saw one herd which must have contained at least five hundred.

They are generally wild and extremely wary. Mr. Stokes told me that he one day saw through a glass a herd of these animals which evidently had been frightened and were running away at full speed, although they were so far away that he could not distinguish them with his naked eye. The sportsman frequently receives the first notice of their presence by hearing from a long distance their peculiar shrill, neighing note of alarm. If he then looks attentively, he will probably see the herd standing in a line on the side of some distant hill. On approaching nearer, a few more squeals are given, and off they set at an apparently slow, but really quick canter, along some narrow beaten track to a neighboring hill. If, however, by chance, he abruptly meets a single animal, or several together, they will generally stand motionless and intently gaze at him, then perhaps move on a few yards, turn round, and look again. What is the cause of this difference in their shyness? Do they mistake a man in the distance for their chief enemy, the puma? Or does curiosity overcome their timidity?

The primary purpose of the first paragraph is __________.

Adapted from "The Colors of Animals" by Sir John Lubbock in A Book of Natural History (1902, ed. David Starr Jordan)

The color of animals is by no means a matter of chance; it depends on many considerations, but in the majority of cases tends to protect the animal from danger by rendering it less conspicuous. Perhaps it may be said that if coloring is mainly protective, there ought to be but few brightly colored animals. There are, however, not a few cases in which vivid colors are themselves protective. The kingfisher itself, though so brightly colored, is by no means easy to see. The blue harmonizes with the water, and the bird as it darts along the stream looks almost like a flash of sunlight.

Desert animals are generally the color of the desert. Thus, for instance, the lion, the antelope, and the wild donkey are all sand-colored. “Indeed,” says Canon Tristram, “in the desert, where neither trees, brushwood, nor even undulation of the surface afford the slightest protection to its foes, a modification of color assimilated to that of the surrounding country is absolutely necessary. Hence, without exception, the upper plumage of every bird, and also the fur of all the smaller mammals and the skin of all the snakes and lizards, is of one uniform sand color.”

The next point is the color of the mature caterpillars, some of which are brown. This probably makes the caterpillar even more conspicuous among the green leaves than would otherwise be the case. Let us see, then, whether the habits of the insect will throw any light upon the riddle. What would you do if you were a big caterpillar? Why, like most other defenseless creatures, you would feed by night, and lie concealed by day. So do these caterpillars. When the morning light comes, they creep down the stem of the food plant, and lie concealed among the thick herbage and dry sticks and leaves, near the ground, and it is obvious that under such circumstances the brown color really becomes a protection. It might indeed be argued that the caterpillars, having become brown, concealed themselves on the ground, and that we were reversing the state of things. But this is not so, because, while we may say as a general rule that large caterpillars feed by night and lie concealed by day, it is by no means always the case that they are brown; some of them still retaining the green color. We may then conclude that the habit of concealing themselves by day came first, and that the brown color is a later adaptation.

Why is it considered especially vital for desert animals to match the color of the desert?