All SSAT Upper Level Reading Resources
Example Questions
Example Question #131 : Narrative Science Passages
"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 first paragraph provides all of the following information EXCEPT __________.
watering the body of the cactus can be harmful to the plant
cacti lack an outer coating to protect them from water loss
cacti are best suited to the desert
cacti can rot if watered incorrectly
frequency of watering should vary based on the season
cacti lack an outer coating to protect them from water loss
The passage states the opposite of the answer choice "it is covered with a waxy coating that prevents water loss through evaporation." The rest of the answer choices are all correct information, which is provided in the first paragraph.
Example Question #132 : Narrative Science Passages
"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 passage addresses all of the following EXCEPT __________.
what to do when pricked by a cactus thorn
how often to water a cactus
how water flows through a cactus from the roots
ideal pot size
how to tell cacti apart from other plants
how water flows through a cactus from the roots
The passage addresses that watering the body of the cactus can have harmful effects, and therefore one should water the roots only; however, it does not discuss the biological mechanism behind how the cactus transports water upward to the body (against the force of gravity).
Example Question #132 : 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.
According to this passage, why were astronomical bodies so important to the emergence of science?
They were once believed to be gods, but by showing that they were not such, humanity was able to believe in scientific thought.
Being above the earth's surface, they seem to encompass the whole of the world.
None of the other answers
Their beauty encouraged continuous speculation.
They exhibit a great deal of regularity.
They exhibit a great deal of regularity.
The key sentence for this question is, "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." The idea is that for prehistoric humanity, the stars and planets likely provided the first example of regularity in our day-to-day experience. Though many of our experiences seem random, the stars do indeed continue in their courses and the sun has its own repeating path. Hence, they began to see that the world had regular patterns—not all is chaos.
Example Question #21 : Understanding The Content Of Natural Science Passages
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 is a reason for how Darwin’s ideas provided a powerful tool?
They gave the most details about how the human species differs from apes.
They provided the complete history of life on earth.
They enabled scientists to see certain groups of data as single, intelligible wholes.
They helped to reorganize the sciences along historical lines.
None of the other answers
They enabled scientists to see certain groups of data as single, intelligible wholes.
The key phrase in the passage for this question is "introducing order into masses of uncorrelated facts." The idea is that Darwin's theories provide a tool by enabling this sort of process of data gathering. Uncorrelated facts are ones that have no order (no co-relation to each other). The idea here is that Darwin's insights helped to provide context to such data, helping to organize them. This made the insights into a powerful tool for science (because inquiry is difficult where there is no order at all).
Example Question #21 : Locating Details In Narrative Science Passages
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.
Based on this passage, what was the role of Herbert Spencer in the history of evolutionary doctrine?
He was the only real source from which Darwin drew his thought.
His thought had aspects related to evolution as a theme in certain social sciences.
In many ways, his thought presaged that of Darwin's, predicting several major aspects of Darwin's theories.
None of the other answers
His thought had no major relation to thought pertaining to evolution.
His thought had aspects related to evolution as a theme in certain social sciences.
In the passage, it is said that few naturalists focused on evolution or the descent/ascent of man before Darwin's day. "Naturalists" would be "natural scientists." The parenthetical remark about Spencer makes sure that the reader knows, however, that Spencer did pay attention to it "in the psychological domain." Some argue that he was influential to Darwin, but that is not discussed here. However, we can say that his thought did contain aspects that applied the idea of evolution to certain branches of the social sciences.
Example Question #34 : Main Idea, Details, Opinions, And Arguments In Narrative 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.
According to the passage, what is the source of modern science?
None of the other answers
Renaissance scientists
Greek astronomy
Renaissance humanists
Egyptian mathematics
None of the other answers
This passage does not really provide a direct history of the "rise of science" and its history. It does provide examples of a certain outlook, using Egypt, the Near East, and Greece as examples. However, none of these are claimed to be the primary ancestors of science.
Example Question #37 : Main Idea, Details, Opinions, And Arguments In Narrative 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 gives the best example of the “static worldview” discussed in the second paragraph?
"In many ways, this situation changed dramatically with the arrival of Darwinism."
"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."
"Among the things that had to change in light of Darwin’s work was the very view of science held by most people."
"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."
"Though there might be many different kinds of creatures, the kinds themselves were not believed to change."
Among the answer choices provided, only one implies an example of the static worldview that preceded Darwin. The answer states that the kinds of creatures were believed not change. This is an example of an outlook that believes things to be unchanging.
Example Question #2 : Identifying And Analyzing Details In Science Passages
"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.
Which of the following would be a direct consequence of belief in geocentrism?
That the sun is stationary
That all bodies in space have independent orbits
That the earth does not move
That even the stars in space move
That the universe is finite in size
That the earth does not move
The theory of geocentrism held that the earth was the center of the solar system (indeed of all things) and that it was fixed in its location. This means that the earth presumably did not move at all. It was "a fixed point in reference to the rest of the visible bodies." They all rotated around it.
Example Question #2 : Comparing And Contrasting Ideas 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.”
How does the quotation from Mr. Gosse relate to the evidence provided by other scientists earlier in the passage?
It contradicts the previous evidence and supports a different hypothesis.
It has nothing to do with the previous evidence.
It supports the same conclusions that the previous evidence supports.
It suggests that some of the previous evidence may be true, but some may be false.
It suggests that the earlier evidence applies not only to hummingbirds but to another type of bird as well.
It supports the same conclusions that the previous evidence supports.
Let’s consider what Mr. Gosse is saying. The passage says, “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.’” Paraphrasing that, Mr. Gosse is saying that he has seen hummingbirds contort themselves in the air and he’s pretty sure they’re doing this in order to catch insects. The evidence provided by scientists earlier in the passage supports the idea that hummingbirds eat insects, just like Mr. Gosse’s does. We can’t say that Gosse’s evidence contradicts the earlier evidence, suggests that some of it may be false, or has nothing to do with the previous evidence. It also doesn’t suggest that the previous evidence can be applied to birds other than hummingbirds, because Mr. Gosse says that he is only discussing hummingbirds and we are to infer that the Polytmus is a hummingbird. So, the correct answer is that “it supports the same conclusions that the previous evidence supports.”
Example Question #3 : Comparing And Contrasting In 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 does the author contrast in this passage?
Hummingbirds with long tails and hummingbirds with short tails
Hummingbirds that eat flower nectar and hummingbirds that eat insects
The results of feeding a hummingbird insects and the results of feeding a hummingbird flower nectar
The author’s opinion about what hummingbirds eat and Mr. Gosse’s opinion about what hummingbirds eat
The beliefs of historical scientists and the beliefs of scientists of the author’s time
The beliefs of historical scientists and the beliefs of scientists of the author’s time
Nowhere in the passage is the feeding of hummingbirds by humans mentioned, so “The results of feeding a hummingbird insects and the results of feeding a hummingbird flower nectar” cannot be correct. While a hummingbird with a long tail, the Polytmus, is mentioned, it is not contrasted with any short-tailed hummingbirds. The author appears to agree with Mr. Gosse’s opinion about what hummingbirds eat, so “The author’s opinion about what hummingbirds eat and Mr. Gosse’s opinion about what hummingbirds eat” cannot be correct either. This leaves us with “Hummingbirds that eat flower nectar and hummingbirds that eat insects” and “the beliefs of historical scientists and the beliefs of scientists of the author’s time.” While the passage is concerned with what hummingbirds eat, it doesn’t suggest that some types of hummingbirds eat only nectar and others eat only insects. Hummingbirds are considered as an entire group; they’re never divided into “hummingbirds that eat insects” and “hummingbirds that eat flower nectar.” This leaves us with one answer choice, the correct one: “The beliefs of historical scientists and the beliefs of scientists of the author’s time.” These beliefs are contrasted in the paragraph’s second sentence: “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.”