Adapted from Ice-Caves of France and Switzerland by 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.

When the external frost of winter comes on, the 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.

In explanation of these phenomena, Bell threw out 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, nitre, 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.

Which of these is the best antonym of the underlined word “partially,” as it is used in this passage?

Adapted from A Catechism of Familiar Things: Their History and the Events Which Led to Their Discovery by the Benziger Brothers (1881)

Twilight is the light from the first dawning of day to the rising of the sun and again between its setting and the last remains of day. Without twilight, the sun's light would appear at its rising, and disappear at its setting, instantly, and we should experience a sudden transition from the brightest sunshine to the most complete obscurity. The duration of twilight is different in different climates, and in the same places it varies at different periods of the year.

The underlined word “obscurity” most nearly means __________.

"Interpreting the Copernican Revolution" by Matthew Minerd (2014)

The expressions of one discipline can often alter the way that other subjects understand themselves. Among such cases are numbered the investigations of Nicolaus Copernicus. Copernicus is best known for his views concerning heliocentrism, a view which eventually obliterated many aspects of the ancient/medieval worldview, at least from the standpoint of physical science. It had always been the natural view of mankind that the earth stood at the center of the universe, a fixed point in reference to the rest of the visible bodies. The sun, stars, and planets all rotated around the earth.

With time, this viewpoint became one of the major reference points for modern life. It provided a provocative image that was used—and often abused—by many people for various purposes. For those who wished to weaken the control of religion on mankind, it was said that the heliocentric outlook proved man’s insignificance. In contrast with earlier geocentrism, heliocentrism was said to show that man is not the center of the universe. He is merely one small being in the midst of a large cosmos. However, others wished to use the “Copernican Revolution” in a very different manner. These thinkers wanted to show that there was another “recentering” that had to happen. Once upon a time, we talked about the world. Now, however, it was necessary to talk of man as the central reference point. Just as the solar system was “centered” on the sun, so too should the sciences be centered on the human person.

However, both of these approaches are fraught with problems. Those who wished to undermine the religious mindset rather misunderstood the former outlook on the solar system. The earlier geocentric mindset did not believe that the earth was the most important body in the heavens. Instead, many ancient and medieval thinkers believed that the highest “sphere” above the earth was the most important being in the physical universe. Likewise, the so-called “Copernican Revolution” in physics was different from the one applied to the human person. Copernicus’ revolution showed that the human point of view was not the center, whereas the later forms of “Copernican revolution” wished to show just the opposite.

Of course, there are many complexities in the history of such important changes in scientific outlook. Nevertheless, it is fascinating to see the wide-reaching effects of such discoveries, even when they have numerous, ambiguous effects.

What is meant by “heliocentrism”?

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.

Based on the context in which it is used in the first paragraph, what is the meaning of the underlined word “acme”?

Adapted from “Birds in Retreat” in “Animal Defences—Active Defence” in 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)

Among the large running birds are forms, like the African ostrich, in which the absence of powers of flight is largely compensated by the specialization of the legs for the purpose of rapid movement on the ground. For straightforward retreat in open country nothing could be more effective; but another kind of adaptation is required in birds like rails, which are deficient in powers of flight, and yet are able to run through thickly-growing vegetation with such rapidity as to commonly elude their enemies. This is rendered possible by the shape of their bodies, which are relatively narrow and flattened from side to side, so as to easily slip between the stems of grasses, rushes, and similar plants. Anyone who has pursued our native land-rail or corn-crake with intent to capture will have noted how extremely difficult it is even to get within sight of a bird of this sort.

Certain birds, unfortunately for themselves, have lost the power of flight without correspondingly increased powers of running, and have paid the penalty of extinction. Such an arrangement, as might be anticipated, was the result of evolution in islands devoid of any predatory ground-animals, and a classic example of it is afforded by the dodo and its allies, birds related to the pigeons. The dodo itself was a large and clumsy-looking species that at one time abounded in the island of Mauritius, which, like oceanic islands generally, possessed no native mammals, while its indigenous reptiles were only represented by lizards. The ubiquitous sailor, however, and the animals (especially swine) which he introduced, brought about the extinction of this helpless bird in less than a century after its first discovery in 1598. Its memory is now only kept green by a few contemporary drawings and descriptions, certain museum remains, and the proverb "as extinct as a dodo.” A similar fate must overtake any organism suddenly exposed to new and unfavorable conditions, if devoid of sufficient plasticity to rapidly accommodate itself to the altered environment.

Based on the way in which it is used in the passage, what is the meaning of the underlined word “ubiquitous”?

"Cacti" by Ami Dave (2013)

Cacti are plants suited to the desert, and we must always keep this factor in mind when growing ornamental cacti in our gardens, for it helps us provide cacti with conditions that allow them to survive and thrive. For example, a cactus should never be watered over its body, as it will start to rot. This is because it is covered with a waxy coating which prevents water loss through evaporation. When one waters the cactus over its body, the waxy coating is washed away and the plant begins to rot. The amount of water that one must supply to the cactus is very much dependent upon the season and upon the climate of the place. During the summer season one should water cacti every four days, whereas in the rainy season, once every fifteen days is quite enough.

Cacti need a minimum of two and a half hours of sunlight per day; however, they should not be kept in the sun all day because they may wrinkle when exposed to too much bright sunlight. Unlike other plants, cacti produce carbon dioxide during the day and oxygen during the night, so they are ideal plants to be kept in bedrooms to freshen up the air at night.

If a cactus is to thrive and prosper, the size of the pot in which it is grown needs to be monitored carefully. The pot should always be a little smaller than the plant itself because it is only when the plant has to struggle to survive that it will thrive. If the pot is too spacious and the plant does not need to struggle, chances are that the cactus will die. Similarly, if a cactus shows no signs of growth, stop watering it. Watering should be resumed only when the plant begins to grow again.

The substrata of a cactus pot is ideally composed of pieces of broken bricks at the bottom, followed by a layer of charcoal above the bricks, and then coarse sand and pebbles above the charcoal. Leaf mould is the best manure.

Grafting cacti is very simple. A very small piece of the cactus plant should be stuck with tape to the plant that needs grafting. The smaller the piece, the easier it is to graft. To reproduce cacti, one has to simply cut off a piece of the cactus, allow it to dry for a few days, and then place it over the cacti substrate. It will automatically develop roots.

It is very easy to differentiate between cacti and other plants that look like cacti. All cacti have fine hair at the base of each thorn. The so-called “thorns” are in fact highly modified leaves which prevent loss of water through transpiration. If one ever gets pricked by cacti thorns, one should take tape, place it over the area where the thorns have penetrated the skin, and then peel it off. All of the thorns will get stuck to the tape and will be removed.

The term "substrata" as it is used in the passage refers to __________.

Adapted from "Taking a Second Look: An Analysis of Genetic Markers in Species Relatedness" by Joseph Ritchie (2014)

Phylogenetics is the study of genetic composition in various species and is used by evolutionary biologists to investigate similarities in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are used to construct mathematical matrices that aid in determining evolutionary ties through the investigation of percentage similarities. The study of these matrices helps to expose evolutionary relationships between species that may not have the same overt characteristics.

Species adapt and evolve based on the pressures that exist in their environment. Climate, food source, and habitat availability are only a few factors that act on species adaptation. These stressors can alter the physical characteristics of organisms. This divergence in evolution has made it difficult to determine the interrelatedness of organisms by analyzing their physical characteristics alone.

For instance, looking only at physical characteristics, the ghost bat resembles a pigeon more than a spider monkey; however, phylogenetics has found that the amino acid sequences that construct the beta hemoglobin molecules of bats are twenty percent more similar to those of mammalian primates than those of birds. This helps reject the assumption that common physical characteristics between species are all that is needed to determine relatedness.

The differences produced by divergent evolution observed in the forest-dwelling, arboreal spider monkey and the nocturnal, airborne ghost bat can be reconciled through homology. Homologous characteristics are anatomical traits that are similar in two or more different species. For instance, the bone structure of a spider monkey’s wrist and fingers greatly resembles that of a bat’s wing or even a whale’s fin. These similarities are reinforced by phylogenetic evidence that supports the idea that physically dissimilar species can be evolutionarily related through anatomical and genetic similarities.

The anatomical similarities between a horse's legs and a seal's flippers is best explained by which of the following?

Adapted from Rambles in the Mammoth Cave, during the Year 1844 by Alexander Clark Bullitt (1845)

Pensico Avenue averages about fifty feet in width with a height of about thirty feet, and is said to be two miles long. It unites in an eminent degree the truly beautiful with the sublime, and is highly interesting throughout its entire extent. For a quarter of a mile from the entrance, the roof is beautifully arched, about twelve feet high and sixty wide, and formerly was encrusted with rosettes and other formations, nearly all of which have been taken away or demolished, leaving this section of the Cave quite denuded. The walking here is excellent; a dozen persons might run abreast for a quarter of a mile to Bunyan's Way, a branch of the avenue leading on to the river. At this point the avenue changes its features of beauty and regularity, for those of wild grandeur and sublimity, which it preserves to the end. The way, no longer smooth and level, is frequently interrupted and turned aside by huge rocks, which lie tumbled around in all imaginable disorder. The roof now becomes very lofty and imposingly magnificent; its long, pointed, or lancet arches, forcibly reminding you of the rich and gorgeous ceilings of the old Gothic cathedrals, at the same time solemnly impressing you with the conviction that this is a "building not made with hands." No one, not dead to all the more refined sensibilities of our nature, but must exclaim, in beholding the sublime scenes which here present themselves, this is not the work of man! No one can be here without being reminded of the all pervading presence of the great "Father of all."

"What, but God, pervades, adjusts and agitates the whole!"

Not far from the point at which the avenue assumes the rugged features, which now characterize it, we separated from our guide, he continuing his straight-forward course, and we descending gradually a few feet and entering a tunnel of fifteen feet wide on our left, the ceiling twelve or fourteen feet high, perfectly arched and beautifully covered with white incrustations, very soon reached the Great Crossings. Here the guide jumped down some six or eight feet from the avenue which we had left, into the tunnel where we were standing, and crossing it, climbed up into the avenue, which he pursued for a short distance or until it united with the tunnel, where he again joined us. In separating from, then crossing, and again uniting with the avenue, it describes with it something like the figure 8. The name, “Great Crossings,” is not unapt. It was however, not given, as our intelligent guide veritably assured us, in honor of the Great Crossings where the man lives who killed Tecumseh, but because two great caves cross here; and moreover said he, "the valiant Colonel ought to change the name of his place, as no two places in a state should bear the same name, and this being the great place ought to have the preference."

Not very far from this point, we ascended a hill on our left, and walking a short distance over our shoe-tops in dry nitrous earth in a direction somewhat at a right angle with the avenue below, we arrived at the Pine Apple Bush, a large column composed of a white, soft, crumbling material, with bifurcations extending from the floor to the ceiling. At a short distance, either to the right or left, you have a fine view of the avenue some twenty feet below, both up and down. Why this crumbling stalactite is called the Pine Apple Bush, I cannot divine. It stands however in a charming, secluded spot, inviting to repose; and we luxuriated in inhaling the all-inspiring air, while reclining on the clean, soft, and dry saltpeter earth.

Which of these is the best synonym to the underlined word “secluded” as it is used in this passage?

Adapted from Rambles in the Mammoth Cave, during the Year 1844 by Alexander Clark Bullitt (1845)

Pensico Avenue averages about fifty feet in width with a height of about thirty feet, and is said to be two miles long. It unites in an eminent degree the truly beautiful with the sublime, and is highly interesting throughout its entire extent. For a quarter of a mile from the entrance, the roof is beautifully arched, about twelve feet high and sixty wide, and formerly was encrusted with rosettes and other formations, nearly all of which have been taken away or demolished, leaving this section of the Cave quite denuded. The walking here is excellent; a dozen persons might run abreast for a quarter of a mile to Bunyan's Way, a branch of the avenue leading on to the river. At this point the avenue changes its features of beauty and regularity, for those of wild grandeur and sublimity, which it preserves to the end. The way, no longer smooth and level, is frequently interrupted and turned aside by huge rocks, which lie tumbled around in all imaginable disorder. The roof now becomes very lofty and imposingly magnificent; its long, pointed, or lancet arches, forcibly reminding you of the rich and gorgeous ceilings of the old Gothic cathedrals, at the same time solemnly impressing you with the conviction that this is a "building not made with hands." No one, not dead to all the more refined sensibilities of our nature, but must exclaim, in beholding the sublime scenes which here present themselves, this is not the work of man! No one can be here without being reminded of the all pervading presence of the great "Father of all."

"What, but God, pervades, adjusts and agitates the whole!"

Not far from the point at which the avenue assumes the rugged features, which now characterize it, we separated from our guide, he continuing his straight-forward course, and we descending gradually a few feet and entering a tunnel of fifteen feet wide on our left, the ceiling twelve or fourteen feet high, perfectly arched and beautifully covered with white incrustations, very soon reached the Great Crossings. Here the guide jumped down some six or eight feet from the avenue which we had left, into the tunnel where we were standing, and crossing it, climbed up into the avenue, which he pursued for a short distance or until it united with the tunnel, where he again joined us. In separating from, then crossing, and again uniting with the avenue, it describes with it something like the figure 8. The name, “Great Crossings,” is not unapt. It was however, not given, as our intelligent guide veritably assured us, in honor of the Great Crossings where the man lives who killed Tecumseh, but because two great caves cross here; and moreover said he, "the valiant Colonel ought to change the name of his place, as no two places in a state should bear the same name, and this being the _great_place ought to have the preference."

Not very far from this point, we ascended a hill on our left, and walking a short distance over our shoe-tops in dry nitrous earth in a direction somewhat at a right angle with the avenue below, we arrived at the Pine Apple Bush, a large column composed of a white, soft, crumbling material, with bifurcations extending from the floor to the ceiling. At a short distance, either to the right or left, you have a fine view of the avenue some twenty feet below, both up and down. Why this crumbling stalactite is called the Pine Apple Bush, I cannot divine. It stands however in a charming, secluded spot, inviting to repose; and we luxuriated in inhaling the all-inspiring air, while reclining on the clean, soft, and dry saltpeter earth.

As it is used in the passage, the underlined word “encrusted” most nearly means __________.

Adapted from "Birds’ Nests" by John Burroughs in A Book of Natural History (1902, ed. David Starr Jordan)

How alert the birds are, even when absorbed in building their nests! In an open space in the woods, I see a pair of cedar-birds collecting moss from the top of a dead tree. Following the direction in which they fly, I soon discover the nest placed in the fork of a small soft-maple, which stands amid a thick growth of wild-cherry trees and young beeches. Carefully concealing myself beneath it, without any fear that the workmen will hit me with a chip or let fall a tool, I await the return of the busy pair. Presently I hear the well-known note, and the female sweeps down and settles unsuspectingly into the half-finished structure. Hardly have her wings rested, before her eye has penetrated my screen, and with a hurried movement of alarm, she darts away. In a moment, the male, with a tuft of wool in his beak (for there is a sheep pasture near), joins her, and the two reconnoitre the premises from the surrounding bushes. With their beaks still loaded, they move around with a frightened look, and refuse to approach the nest till I have moved off and lain down behind a log. Then one of them ventures to alight upon the nest, but, still suspecting all is not right, quickly darts away again. Then they both together come, and after much peeping and spying about, and apparently much anxious consultation, cautiously proceed to work. In less than half an hour, it would seem that wool enough has been brought to supply the whole family, real and prospective, with socks, if needles and fingers could be found fine enough to knit it up. In less than a week, the female has begun to deposit her eggs—four of them in as many days—white tinged with purple, with black spots on the larger end. After two weeks of incubation, the young are out.

The underlined word “concealing” most nearly means __________.