PSAT Critical Reading : Natural Science Passages

Study concepts, example questions & explanations for PSAT Critical Reading

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Example Questions

Example Question #171 : Passage Based Questions

"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.

How are two uses of the image of heliocentrism contrasted in this passage?

Possible Answers:

One calls for detached peace while the other is likely to breed wars.

One calls for scientific detachment while the other calls for engagement in the world of culture.

One implies the insignificance of the human person while the other implies humanity's greatness.

One is primarily scientific while the other is religious at its core.

None of the other answers

Correct answer:

One implies the insignificance of the human person while the other implies humanity's greatness.

Explanation:

The general contrast is between "man, the speck on a rock" and "man, the center of all things." The idea for one view is that the human person is insignificant in comparison to the rest of the universe, which dwarfs his little life on Earth. The other view makes the human person so significant that the study of human life is central.

Example Question #2 : Textual Relationships In Science Passages

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.

Which of the following does the passage directly compare?

Possible Answers:

The relative warmth of feathers and down as insulating materials

The use of eider down in bedding in North America and in Iceland

Ducks that nest on the Labrador coast and ducks that nest in Iceland

The price of down in Iceland and North America

The nesting habits of hunted and protected ducks

Correct answer:

The nesting habits of hunted and protected ducks

Explanation:

Of the given answer choices, the passage only compares “the nesting habits of hunted and protected ducks.” It does this when the author says, “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.” The price of down is never mentioned in the passage, and while feathers and down are both mentioned, they are not compared. Similarly, the use of eider down in bedding is mentioned, but its use in North America and in Iceland isn’t compared. Finally, while ducks that nest on the Labrador coast and ducks that nest in Iceland are each described, they are not directly compared.

Example Question #102 : Natural Sciences

Adapted from "Recent Views as to Direct Action of Light on the Colors of Flowers and Fruits" in Tropical Nature, and Other Essays by 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.

In this passage, the author __________.

Possible Answers:

disagrees with the "recent writer" quoted in the first paragraph, but agrees with Grisebach

disagrees with Martins but agrees with Grisebach

disagrees with all of the writers and scientists mentioned in the passage

agrees with all of the writers and scientists mentioned in the passage

disagrees with Hooker but agrees with Martins

Correct answer:

disagrees with the "recent writer" quoted in the first paragraph, but agrees with Grisebach

Explanation:

Answering this question requires you to read closely, as many theories are mentioned throughout the passage and keeping track of them can be quite challenging. In the first paragraph, the writer quotes a "recent writer," who then quotes evidence in the form of observations by M. Grisebach and M. Ch. Martins. In the second paragraph, the writer says that he agrees with the evidence of the "recent writer" (in other words, Grisebach and Martins), but not with the theory the "recent writer" has come up with to explain that evidence. So, the author disagrees with the "recent writer," but agrees with Grisebach, because the author goes on to quote Grisebach's own theory, with which the author agrees.

Example Question #124 : Narrative Science Passages

Adapted from “Humming-Birds: As Illustrating the Luxuriance of Tropical Nature” in Tropical Nature, and Other Essays by 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 remain on 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.”

What do Azara, Bullock, and Waterton have in common?

Possible Answers:

They are all types of hummingbirds.

They are all scientists who think hummingbirds eat insects.

They are all scientists who think hummingbirds eat flower nectar.

They are all types of birds that eat insects.

They are all critics of the writer and disagree with his theory.

Correct answer:

They are all scientists who think hummingbirds eat insects.

Explanation:

Azara, Bullock, and Waterton are all mentioned near the beginning of the passage. The author writes, “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.” He then mentioned the following:

(1) "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."

(2) "Bullock, in Mexico, declares that he saw them catch small butterflies, and that he found many kinds of insects in their stomachs."

(3) "Waterton made a similar statement."

The author is suggesting that Azara, Bullock, and Waterton fall into the group of “every close observer of their habits.” The three also make statements about hummingbirds. From this, we can narrow down our answers to three choices: that Azara, Bullock, and Waterton are critics of the author, scientists who think hummingbirds eat insects, or scientists who think hummingbirds eat flower nectar. Nowhere in the passage do the statements made by these writers appear to contradict the author’s opinion, so we can discard the idea that Azara, Bullock, and Waterton are critics of the author. So, are they saying that hummingbirds eat flower nectar or insects? They author says that early observers of hummingbirds thought that they eat flower nectar, but that more recent scientists—like the three quoted—think that they eat insects. The statements made by each also relate to hummingbirds eating insects, so the correct answer is “They are all scientists who think hummingbirds eat insects.”

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