SSAT Upper Level Reading : Making Inferences in Narrative Science Passages

Study concepts, example questions & explanations for SSAT Upper Level Reading

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Example Questions

Example Question #11 : Making Inferences In Narrative Science Passages

Adapted from An Introduction to Astronomy by Forest Ray Moulton (1916 ed.)

It is doubtful if any important scientific idea ever sprang suddenly into the mind of a single man. The great intellectual movements in the world have had long periods of preparation, and often many men were groping for the same truth, without exactly seizing it, before it was fully comprehended.

The foundation on which all science rests is the principle that the universe is orderly, and that all phenomena succeed one another in harmony with invariable laws. Consequently, science was impossible until the truth of this principle was perceived, at least as applied to a limited part of nature.

The phenomena of ordinary observation, as, for example, the weather, depend on such a multitude of factors that it was not easy for men in their primitive state to discover that they occur in harmony with fixed laws. This was the age of superstition, when nature was supposed to be controlled by a great number of capricious gods whose favor could be won by childish ceremonies. Enormous experience was required to dispel such errors and to convince men that the universe is one vast organization whose changes take place in conformity with laws which they can in no way alter.

The actual dawn of science was in prehistoric times, probably in the civilizations that flourished in the valleys of the Nile and the Euphrates. In the very earliest records of these people that have come down to modern times it is found that they were acquainted with many astronomical phenomena and had coherent ideas with respect to the motions of the sun, moon, planets, and stars. It is perfectly clear from their writings that it was from their observations of the heavenly bodies that they first obtained the idea that the universe is not a chaos. Day and night were seen to succeed each other regularly, the moon was found to pass through its phases systematically, the seasons followed one another in order, and in fact the more conspicuous celestial phenomena were observed to occur in an orderly sequence. It is to the glory of astronomy that it first led men to the conclusion that law reigns in the universe.

John Stuart Mill once wrote an essay on "Tideology" to discuss the social sciences, which he compared to knowledge of tides, about which he noted the concurrence of many different causes. Based on this passage, what do you think this means about the social sciences?

Possible Answers:

They have always been around, for the tides have intrigued human persons from time immemorial.

Their emergence was crucial to the beginning of science.

None of the other answers

It is difficult to find regularity in their data.

They are well developed, given the many other developments in science.

Correct answer:

It is difficult to find regularity in their data.

Explanation:

In this passage, the author discusses the fact that it is very difficult to have science when there is a concurrence of many factors that are related to each other only with difficulty. If Mill was claiming that this was the case for the social sciences, it is safe to assume (based on our passage's reasoning, at least) that such sciences discover regularity only with great difficulty.

Example Question #622 : Act Reading

Adapted from “Darwin’s Predecessors” by J. Arthur Thomson in Evolution 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 it current 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.

In the third place, Darwin contributed largely to 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.

Which of the following sentences might we presume could have been in Darwin’s work?

Possible Answers:

The collected data, though at odds with what was formerly held, provide a thorough basis for questioning certain details of the previous theories.

With only one or two samples, we can overturn the former positions with ease.

The lunatic former position can now be set aside as a ghost from our past history.

The ignorance of those basing their arguments upon prejudices has occluded their ability to reason at all.

Without considering a single detail, it is possible to see that the opposing view is untenable.

Correct answer:

The collected data, though at odds with what was formerly held, provide a thorough basis for questioning certain details of the previous theories.

Explanation:

The key sentence for this question is: "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."

All of the incorrect answers are either rude to the other parties or barely claim any facts for the position. According to the author of this passage at least, Darwin was critical but fair-minded. This is best represented by the prudently stated sentence, "The collected data, though at odds with what was formerly held, provide a thorough basis for questioning certain details of the previous theories."

Example Question #22 : Making Inferences About The Author Or Natural Science Passage Content

Adapted from “Darwin’s Predecessors” by J. Arthur Thomson in Evolution 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 it current 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.

In the third place, Darwin contributed largely to 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.

Which of the following describes the descriptions provided by Darwin?

Possible Answers:

Paleontological

Historical

Precise

Vague

Indeterminate

Correct answer:

Precise

Explanation:

In the passage, it is said that many of the descriptions before Darwin's time were "suggestions of a more or less vague description." The passage is contrasting his work to these earlier descriptions, which lacked details (or at least are presented as so lacking in details). The only option that provides such a contrast is "precise."

Example Question #6 : Making Inferences And Predictions In Science Passages

"Darwinism's Effect on Science" by Matthew Minerd (2014)

For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.

In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.

Which of the following is implied in this passage about modern physics?

Possible Answers:

It was singularly new in the history of scientific thought.

It was viewed as the science that explained all others.

It was freed of superstition during the Renaissance.

None of the other answers

It was dogmatically tied to Renaissance ideas.

Correct answer:

It was viewed as the science that explained all others.

Explanation:

The best sentence for answering this question is, "Its static laws appeared to be the unchanging principles of all motion and life on earth." The first paragraph implies that physics appeared to provide the principles needed for explaining all things. It would therefore appear to many to be the "science of sciences." (Indeed, this has been the temptation in real history as well, though that is another, complex story!)

Example Question #1 : Making Inferences In Natural Science Passages

"Darwinism's Effect on Science" by Matthew Minerd (2014)

For much of the history of human thought, the sciences have studied subjects that seemed to be eternal and unchanging. Even the basic laws of the Nile’s flooding were investigated in the hopes of finding never-altering laws. Similarly, the scientific investigations of the ancient Near East and Greece into the regular laws of the stars ultimately looked for constant patterns. This overall pattern of scientific reasoning has left deep marks on the minds of almost all thinkers and found its apotheosis in modern physics. From the time of the early renaissance to the nineteenth century, physics represented the ultimate expression of scientific investigation for almost all thinkers. Its static laws appeared to be the unchanging principles of all motion and life on earth. By the nineteenth century, it had appeared that only a few details had to be “cleared up” before all science was basically known.

In many ways, this situation changed dramatically with the arrival of Darwinism. It would change even more dramatically in early twentieth-century physics as well. Darwin’s theories of evolution challenged many aspects of the “static” worldview. Even those who did not believe that a divine being created an unchanging world were shaken by the new vistas opened up to science by his studies. It had been a long-accepted inheritance of Western culture to believe that the species of living organisms were unchanging in nature. Though there might be many different kinds of creatures, the kinds themselves were not believed to change. The thesis of a universal morphing of types shattered this cosmology, replacing the old world-view with a totally new one. Among the things that had to change in light of Darwin’s work was the very view of science held by most people.

Who was most affected by the changes caused by Darwinism?

Possible Answers:

None of the other answers

Religious zealots

Publishers of science texts

Science teachers

Religious believers

Correct answer:

None of the other answers

Explanation:

There have almost always been controversies about evolution, lasting to our day. Do not bring any of this to your reading of the passage; stick to the text. The general implication in the second paragraph is that everyone was affected by these changes in outlook—believers and non-believers alike. None of the limited groups listed in the answers is sufficient. Therefore, the best choice is "none of the other answers."

Example Question #72 : 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.”

Based on what is said in the passage, the author most likely believes that __________.

Possible Answers:

hummingbirds eat only flower nectar

None of the other answers

hummingbirds eat a mixture of flower nectar and insects, but mostly insects

hummingbirds eat a mixture of flower nectar and insects, but mostly flower nectar

hummingbirds eat neither flower nectar nor insects

Correct answer:

hummingbirds eat a mixture of flower nectar and insects, but mostly insects

Explanation:

This is a tricky question because in the passage, the author never directly states his opinion about what hummingbirds eat; readers have to infer it based on the evidence he presents. The author begins the passage by stating that while old scientists used to think hummingbirds ate only flower nectar, modern writers think that they eat “largely, and in some cases wholly,” on insects. He then presents evidence suggesting that hummingbirds eat insects, and in discussing the contents of hummingbirds’ stomachs, says that scientists sometimes find both insects and honey. For the rest of the paragraph, he provides evidence suggesting that hummingbirds eat insects.

What can we infer from this? Well, we can tell that it’s not likely that the author thinks hummingbirds eat only flower nectar, because he provides evidence supporting the idea that they eat insects. This means that we can also discard the answer choice “hummingbirds eat neither flower nectar nor insects.” It’s quite reasonable to think that the author thinks that “hummingbirds eat a mixture of flower nectar and insects” because he mentions that sometimes honey is found along with insects in hummingbirds’ stomachs. So, we need to figure out whether he probably believes that they eat mostly insects or mostly flower nectar. Let’s look at how the author phrases his description of the contents of hummingbirds’ stomachs: “in almost every instance their stomachs have been found full of insects, sometimes, but not generally, mixed with a proportion of honey.” So, if “in almost every instance” the hummingbird stomachs examined were “full of insects,” but “sometimes, but not generally” honey was also found, the correct answer must be “hummingbirds eat a mixture of flower nectar and insects, but mostly insects.”

Example Question #73 : 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.”

Which of the following inferences does the passage expect its readers to make?

Possible Answers:

If a hummingbird consumes flower nectar, this nectar will turn into the honey that can be found in its stomach.

Scientists rarely learn about hummingbirds by dissecting them.

If a hummingbird eats gnats, it will not eat honey.

The author is the first scientist to ever have investigated what hummingbirds eat.

Fly-catchers are a type of insect.

Correct answer:

If a hummingbird consumes flower nectar, this nectar will turn into the honey that can be found in its stomach.

Explanation:

Let’s consider each of the answer choices to identify the correct one.

“The author is the first scientist to ever have investigated what hummingbirds eat.” - This cannot be true, because the author begins the passage by saying “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.” He also cites numerous other scientists’ opinions throughout the passage, so he can’t be the first person to have investigated what hummingbirds eat.

“Fly-catchers are a type of insect.” - The passage mentions fly-catchers in the following sentence: “Many [hummingbirds] 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.” This is a tricky answer choice in that it’s easy to misread the sentence and think that “just like flycatchers” refers to “other small insects” when in fact it refers to the act of “catching.” The sentence is saying that hummingbirds catch insects in the same manner as fly-catchers, not that fly-catchers are a type of insect. Plus, we are being asked to identify an inference readers are expected to make, and if this sentence did mean that fly-catchers were insects, it would be overtly telling us this, and there would be nothing we’d have to infer.

“Scientists rarely learn about hummingbirds by dissecting them.” - This answer choice is proven wrong by the following sentence: “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.”

“If a hummingbird eats gnats, it will not eat honey.” - Given that the questions of whether hummingbirds eat insects or honey and in what proportions is the topic of the passage, it may be easy to choose this answer choice because it seems like the one closest to the passage’s main idea; however, nothing in the passage supports this assertion.

“If a hummingbird consumes flower nectar, this nectar will turn into the honey that can be found in its stomach.” - This is the correct answer! The author initially states that “All the early writers down to Buffon believed that [hummingbirds] lived solely on the nectar of flowers”; however, he later states that “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.” The author does not address the idea that flower nectar and honey could be different substances, and instead expects the reader to treat these as one source of food.

Example Question #11 : Making Inferences In 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.”

Based on the way the term is used in passage, what is “the Polytmus”?

Possible Answers:

A type of hummingbird with a long tail

A species of flower that often attracts hummingbirds

A type of hummingbird with particularly bright coloring

A scientific term for a fledgling hummingbird that cannot yet fly

A type of carnivorous mammal that eats hummingbirds

Correct answer:

A type of hummingbird with a long tail

Explanation:

Let’s look at the spot in the passage where “the Polytmus” is mentioned: 

“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.’” 

From this context, we can tell that the Polytmus isn’t a carnivorous hummingbird-eating mammal, or a species of flower: it is a hummingbird. It is mentioned in the context of flying, so it can’t refer to a fledgling hummingbird that can’t yet fly. So, is it mentioning a type of hummingbird with particularly bright coloring, or one with a long tail? Mr. Gosse mentions the Polytmus in particular because observers can easily see it contort in midair “from the effect that such motions have on the long feathers of the tail.” So, the Polytmus must be “a type of hummingbird with a long tail.”

Example Question #1 : Making Inferences In Natural 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 can we infer from the underlined sentence, “Many [hummingbirds] 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"?

Possible Answers:

All hummingbirds live in the desert.

Gnats are rarely found near bodies of water.

Some hummingbirds live in the desert.

All hummingbirds live near bodies of water.

Some hummingbirds live near bodies of water.

Correct answer:

Some hummingbirds live near bodies of water.

Explanation:

What does the underlined sentence tell us? It refers to “Many” hummingbirds, not “all hummingbirds,” so we can’t infer that what it says holds true for all hummingbirds. This allows us to eliminate the answer choices that begin with “all hummingbirds,” leaving us with “Gnats are rarely found near bodies of water,” “Some hummingbirds live in the desert,” and “Some hummingbirds live near a body of water.” Regarding gnats, the sentence doesn’t suggest that they are rarely found near bodies of water, since it mentions hummingbirds “may be seen catching gnats and other small insects just like fly-catchers” and implies that they do this by “sitting on a dead twig over water, darting off for a time in the air, and then returning to the twig.” We’re down to two answer choices: whether some hummingbirds live in the desert or near a body of water. The sentence doesn’t mention anything about deserts; on the contrary, it tells us that “many” hummingbirds catch gnats. The way that these hummingbirds do this begins with them “sitting on a dead twig over water.” So, we are told that many hummingbirds catch gnats and that in catching gnats, they sit over water. From this, we can infer that many hummingbirds live near bodies of water.

Example Question #21 : Reading Comprehension

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.

Which of the following can we infer based on the passage?

Possible Answers:

Ostriches would likely be as effective at running away from predators in tall grass as in open country.

The land-rail and corn-crake are not well adapted to running through tall grass.

If predatory ground-animals had lived on Mauritius, the dodo would have probably evolved to fly or run.

If sailors had visited Mauritius sooner, dodos might still be alive today.

Lizards were a predator of dodos.

Correct answer:

If predatory ground-animals had lived on Mauritius, the dodo would have probably evolved to fly or run.

Explanation:

This may seem like a tricky question, but let’s consider each of the answer choices individually:

“If sailors had visited Mauritius sooner, dodos might still be alive today.”: The passage doesn’t support this assertion at all. Since the arrival of sailors on New Zealand is identified as the cause of the dodo’s extinction, it doesn’t make sense that the dodo would have survived if the sailors would have arrived earlier; it would probably have gone extinct sooner, based on the passage’s logic.

 “Ostriches would likely be as effective at running away from predators in tall grass as in open country.”: The passage specific disproves this when it says of ostriches and their running abilities, “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 suggests that ostriches are better adapted to surviving in open country than in areas covered by tall grass.

“The land-rail and corn-crake are not well adapted to running through tall grass.”: The passage disproves this answer choice when it describes the ability of rails to run through tall grass: “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.” After this sentence, the author mentions land-rails and corn-crakes’ abilities to evade hunters, so we can assume that these birds are well adapted to running through tall grass.

“Lizards were a predator of dodos.”: This can’t be true, because the passage tells us that “The dodo . . . 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.” Given that when animals that preyed on the dodo were introduced to Mauritius, the dodo went extinct, we can assume that since the lizards and dodos coexisted before this point, the lizards did not prey on the dodos. If this were true, the dodos would likely have learned to run or fly away, which they did not.

This brings us to the remaining answer choice, the correct one: “If predatory ground-animals had lived on Mauritius, the dodo would have probably evolved to fly or run.” The author attributes the dodo’s extinction to the fact that it did not have to adapt and defend itself from any predators before humans introduced new species on Mauritius. From this, we can infer that if those species had been present, the dodo would have learned to fly, or, like the ostrich and the rail, would have learned to run to defend itself.

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