GMAT Verbal : Analyzing Sequence, Organization, and Structure in Natural Science Passages

Study concepts, example questions & explanations for GMAT Verbal

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Example Questions

Example Question #51 : Science Passages

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.

How does the second paragraph relate to the first paragraph?

Possible Answers:

The first paragraph describes birds people eat; the second describes birds people do not eat.

The first paragraph describes a type of flightless birds that has gone extinct; the second describes species of flightless birds that are still living.

The first paragraph describes flightless birds that learned to defend themselves from predators by fleeing them; the second paragraph describes a flightless bird that did not adapt in this way.

The first paragraph discusses predators of flightless birds, the second describes prey of flightless birds.

The first paragraph provides a personal anecdote while the second paragraph provides historical information.

Correct answer:

The first paragraph describes flightless birds that learned to defend themselves from predators by fleeing them; the second paragraph describes a flightless bird that did not adapt in this way.

Explanation:

Examining the two paragraphs, one can find that the first one talks about ostriches and rails, two types of flightless birds that adapted in specific ways to be good at fleeing predators. The second paragraph tells the story of the dodo, a flightless bird that did not have time to develop such adaptations. From here, we can pick out the correct answer: “The first paragraph describes flightless birds that learned to defend themselves from predators by fleeing them; the second paragraph describes a flightless bird that did not adapt in this way.”

As for the other answer choices, nothing in the passage discusses people eating birds, so we can ignore the answer choice “The first paragraph describes birds people eat; the second describes birds people do not eat.” The answer choice “The first paragraph describes a type of flightless birds that has gone extinct; the second describes species of flightless birds that are still living” would be correct if it flipped around the paragraphs to which it refers, but as it is written, it is incorrect. The passage doesn’t say anything about the predators of flightless birds in the first paragraph or the prey of flightless birds in either paragraph, so “The first paragraph discusses predators of flightless birds, the second describes prey of flightless birds” cannot be correct, and since the first paragraph does not provide a personal anecdote, “The first paragraph provides a personal anecdote while the second paragraph provides historical information” cannot be correct either.

Example Question #21 : Science Passages

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 __________.

Possible Answers:

to provide an example color-change in animals that is both aggressive and defensive

to describe an animal that has adapted to an unchanging environment

to describe why stoats and weasels have a hard time hunting Irish hares in winter

to describe the appearance of a stoat in summer

to provide an example of an animal that goes by two different names depending on its appearance

Correct answer:

to provide an example color-change in animals that is both aggressive and defensive

Explanation:

When answering questions about a paragraph’s purpose, it’s helpful to consider how it relates to the rest of the passage as a whole, and to consider what each of the other paragraphs do in the context of the passage. For instance, in this passage, the first paragraph transitions from discussing animal adaptations in unchanging environments to discussing animal adaptations in changing environments. The second paragraph talks about Irish hares as an example of animals that change their fur color. So, what is the point of the third paragraph? While it does “provide an example of an animal that goes by two different names depending on its appearance” and “describe the appearance of a stoat in summer,” neither of these is its main point; these are details, and neither seems to relate that much to the points of the previous paragraphs. Stoats and weasels are not described as specifically hunting Irish hares, and the passage describes how their changing fur color helps them be better hunters, not why they have such a hard time hunting, so “to describe why stoats and weasels have a hard time hunting Irish hares in winter” cannot be the correct answer either. The point of the paragraph cannot be “to describe an animal that has adapted to an unchanging environment” either, because it describes stoats and weasels, animals that adapt to changing environments. This leaves us with one answer, the correct one: “to provide an example color-change in animals that is both aggressive and defensive.” The examples of stoats and weasels both fall into this category, which is contrasted with the purely defensive function of color-change in hares in the passage’s last sentence.

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