SSAT Upper Level Reading : Main Idea, Details, Opinions, and Arguments in Narrative Science Passages
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Example Questions
Example Question #1 : Understanding Main Ideas In Natural 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.
Which of the following best states the main idea of this passage?
The extinction of the dodo can be traced to human causes.
Flightless birds sometimes develop strong running abilities, but if they don’t, they may be threatened with extinction.
The African ostrich’s strong leg muscles makes it well adapted to its environment.
Birds employ a variety of defenses for avoiding predators.
Flightless birds adapt to their particular surroundings.
Flightless birds sometimes develop strong running abilities, but if they don’t, they may be threatened with extinction.
When asked to identify a passage’s main idea, it is important to pick out an answer choice to which all of the paragraphs can relate, but that is not too broad in including things that the passage does not discuss. Considering if each of the answer choices falls into one or another of these categories can help you narrow down your choices. For instance, “Birds employ a variety of defenses for avoiding predators” is far too broad to accurately describer this passage’s main idea. The author only discusses flightless birds, not all birds. “Flightless birds adapt to their particular surroundings” cannot be correct either, as the first paragraph discusses this, but the second paragraph discusses a flightless bird that did not adapt to its surroundings. Since the second paragraph can’t relate to this answer, it can’t be the main idea of the entire passage. Two of the remaining answer choices can be discarded due to their being too detailed: “The African ostrich’s strong leg muscles makes it well adapted to its environment” and “The extinction of the dodo can be traced to human causes.” While the first of these choices is stated in the first paragraph and the second is stated in the second paragraph, neither relates to the other paragraph, or even adequately summarizes the entire paragraph in which it appears. This leaves us with one answer choice, the correct one: “Flightless birds sometimes develop strong running abilities, but if they don’t, they may be threatened with extinction.” Each of the two paragraphs can relate to this answer choice, but it doesn’t include things that the passage doesn’t discuss.
Example Question #252 : Gmat Verbal
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.
One of the main differences between an ostrich and a rail, according to the passage, is __________.
ostriches run over open terrain, and rails run through thick grass
ostriches are smaller than rails
ostriches live in grassy areas whereas rails live in the desert
ostriches are living things whereas rails are inanimate objects
ostriches use their running abilities to catch prey, whereas rails use their running abilities to avoid predators
ostriches run over open terrain, and rails run through thick grass
Ostriches and rails are discussed in the first paragraph. The author says that “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.” The passage then goes on to detail how rails have thin bodies that allow them to dart through the grass. This means that the correct answer is “ostriches run over open terrain whereas rails run through thick grass.”
The passage is describing the rail, a type of bird, and not using the word “rail” to describe part of a train track or a barrier on an elevated area, so “ostriches are living things whereas rails are inanimate objects” cannot be correct. Ostriches are never said to be smaller than rails or predators, so neither “ostriches are smaller than rails” nor “ostriches use their running abilities to catch prey, whereas rails use their running abilities to avoid predators” can be correct. Finally, rails are said to live in areas containing and have adapted to “thickly-growing vegetation” and ostriches are said to have developed a different adaptation suited to “open country,” so “ostriches live in grassy areas whereas rails live in the desert” cannot be correct either.
Example Question #1 : Comparing And Contrasting In 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?
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 provides a personal anecdote while the second paragraph provides historical information.
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 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.
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 #11 : Recognizing The Main Idea In Narrative Science Passages
Adapted from A Catechism of Familiar Things: Their History and the Events Which Led to Their Discovery by the Benziger Brothers (1881)
Twilight is the light from the first dawning of day to the rising of the sun; and again between its setting and the last remains of day. Without twilight, the sun's light would appear at its rising, and disappear at its setting, instantly; and we should experience a sudden transition from the brightest sunshine to the most complete obscurity. The duration of twilight is different in different climates; and in the same places it varies at different periods of the year.
This passage is primarily concerned with __________.
explaining the differences in duration of twilight in different parts of the world
providing a coherent and comprehensive definition of twilight
ridiculing the ancient worship of sunlight
highlighting the importance of twilight
defining how twilight is experienced by people
providing a coherent and comprehensive definition of twilight
In this passage, the author is merely defining what exactly twilight is. It seems to be written as an introductory article for children who are first learning about the subject. The author briefly mentions how people experience twilight and how it is different in different parts of the world, but these are both part of the author’s attempts at “providing a coherent and comprehensive definition.” There is no mention of the ancient worship of sunlight, nor does the author particularly focus on highlighting the importance of twilight.
Example Question #1 : 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.
Which of the following best expresses the main idea of the passage?
All animals that live in a changing environment change color.
Animals like the stoat, the weasel, and the Irish hare are better adapted to changing environments than to unchanging ones.
Certain animals change their fur color to be better predators or better at hiding.
Increased defense is the only reason for an animal to change its fur color.
The Scottish hare changes its fur color.
Certain animals change their fur color to be better predators or better at hiding.
When answering questions about the main idea of a passage, it’s important to pick out an answer choice to which each paragraph relates, but one that isn’t too broad. Some of the answer choices to this question are too specific: “The Scottish hare changes its fur color” is, and we can tell because the first paragraph doesn’t say anything about the Scottish hare, and the third paragraph only mentions it in its last line. “Increased defense is the only reason for an animal to change its fur color” should get your attention due to its use of the word “only”—did we hear anything in the passage about color-changing adaptations being used “only” for defense? No, we heard the opposite, in the passage’s last line: “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 language may be a bit dense here, but what the passage is saying is that the hare uses its color-changing adaptation for defense, but stoats and weasels use it for being better predators and sneaking up on their prey—definitely not a defensive use. Similarly, “All animals that live in a changing environment change color” is making a strong statement due to its use of the word “all.” The passage gives us a few examples of animals that change that live in a changing environment and change their color, but this isn’t enough for us to assume that all animals that live in changing environments act this way.
Example Question #1 : Understanding Organization And Argument In Natural Science Passages
Adapted from "Taking a Second Look: An Analysis of Genetic Markers in Species Relatedness" by Joseph Ritchie (2014)
Phylogenetics is the study of genetic composition in various species and is used by evolutionary biologists to investigate similarities in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are used to construct mathematical matrices that aid in determining evolutionary ties through the investigation of percentage similarities. The study of these matrices helps to expose evolutionary relationships between species that may not have the same overt characteristics.
Species adapt and evolve based on the pressures that exist in their environment. Climate, food source, and habitat availability are only a few factors that act on species adaptation. These stressors can alter the physical characteristics of organisms. This divergence in evolution has made it difficult to determine the interrelatedness of organisms by analyzing their physical characteristics alone.
For instance, looking only at physical characteristics, the ghost bat resembles a pigeon more than a spider monkey; however, phylogenetics has found that the amino acid sequences that construct the beta hemoglobin molecules of bats are twenty percent more similar to those of mammalian primates than those of birds. This helps reject the assumption that common physical characteristics between species are all that is needed to determine relatedness.
The differences produced by divergent evolution observed in the forest-dwelling, arboreal spider monkey and the nocturnal, airborne ghost bat can be reconciled through homology. Homologous characteristics are anatomical traits that are similar in two or more different species. For instance, the bone structure of a spider monkey’s wrist and fingers greatly resembles that of a bat’s wing or even a whale’s fin. These similarities are reinforced by phylogenetic evidence that supports the idea that physically dissimilar species can be evolutionarily related through anatomical and genetic similarities.
Paragraph four of the passage discusses which of the following?
the physiological functions of the spider monkey’s wrist and fingers, the bat’s wing, and the whale’s fin.
the unreliability of physical characteristics in determining species relatedness.
the reasons why a spider monkey’s wrist and fingers can resemble a bat's wing or a whale's fin.
the theory of evolution.
the reasons why a spider monkey’s wrist and fingers can resemble a bat's wing or a whale's fin.
One of paragraph four's central purposes is to give examples of homologous adaptation. It describes how the features of different species can possess anatomical similarities, even if the species are from vastly different habitats. The passage does not discuss the theory of evolution nor the physiological purposes of certain appendages, and the third paragraph, not the fourth, discusses the unreliability of physical characteristics in determining species relatedness.
Example Question #61 : Natural Science Passages
Adapted from "Taking a Second Look: An Analysis of Genetic Markers in Species Relatedness" by Joseph Ritchie (2014)
Phylogenetics is the study of genetic composition in various species and is used by evolutionary biologists to investigate similarities in the molecular sequences of proteins in varying organisms. The amino acid sequences that build proteins are used to construct mathmatical matrices that aid in determining evolutionary ties through the investigation of percentage similarities. The study of these matrices helps to expose evolutionary relationships between species that may not have the same overt characteristics.
Species adapt and evolve based on the pressures that exist in their environment. Climate, food source, and habitat availability are only a few factors that act on species adaptation. These stressors can alter the physical characteristics of organisms. This divergence in evolution has made it difficult to determine the interrelatedness of organisms by analyzing their physical characteristics alone.
For instance, looking only at physical characteristics, the ghost bat resembles a pigeon more than a spider monkey; however, phylogenetics has found that the amino acid sequences that construct the beta hemoglobin molecules of bats are twenty percent more similar to those of mammalian primates than those of birds. This helps reject the assumption that common physical characteristics between species are all that is needed to determine relatedness.
The differences produced by divergent evolution observed in the forest-dwelling, arboreal spider monkey and the nocturnal, airborne ghost bat can be reconciled through homology. Homologous characteristics are anatomical traits that are similar in two or more different species. For instance, the bone structure of a spider monkey’s wrist and fingers greatly resembles that of a bat’s wing or even a whale’s fin. These similarities are reinforced by phylogenetic evidence that supports the idea that physically dissimilar species can be evolutionarily related through anatomical and genetic similarities.
The central idea of this passage is best described by which of the following statements?
Genetic analysis is the only method of studying evolutionary ties and species relatedness.
Despite differences in physical appearance, genetic similarities can aid in determining species relatedness and evolutionary histories.
Phylogenetics is a relatively new area of study and has yet to yield supported conclusions on evolutionary histories.
Understanding divergent evolution is necessary for understanding species relatedness.
Despite differences in physical appearance, genetic similarities can aid in determining species relatedness and evolutionary histories.
This is the correct answer because it is the only statement that is supported by the passage. The passage introduces the field of phylogenetics and the need to explore evolution beyond simple examination of physical characteristics. It does not state which field of study is better or correct. It simply states that they compliment the same cause: the study of relatedness. The other choices are unsupported opinions. The answer choice about divergent evolution is incorrect because while the passage's fourth paragraph is about divergent evolution, the entire passage encompasses many more topics.
Example Question #14 : Main Idea, Details, Opinions, And Arguments In Narrative Science Passages
Adapted from Common Diseases of Farm Animals by R. A. Craig (1916, 2nd ed.)
The common bot-fly of the horse (G. equi) has a heavy, hairy body. Its color is brown, with dark and yellowish spots. The female fly can be seen during the warm weather, hovering around the horse, and darting toward the animal for the purpose of depositing the egg. The color of the egg is yellow, and it adheres firmly to the hair. It hatches in from two to four weeks, and the larva reaches the mouth through the animal licking the part. From the mouth, it passes to the stomach, where it attaches itself to the gastric mucous membrane. Here it remains until fully developed, when it becomes detached and is passed out with the feces. The third stage is passed in the ground. This takes place in the spring and early summer and lasts for several weeks, when it finally emerges a mature fly.
The bot-fly of the ox (H. lineata) is dark in color and about the size of a honey-bee. On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded. The egg reaches the mouth through the animal licking the part. The saliva dissolves the shell of the egg and the larva is freed. It then migrates from the gullet, wanders about in the tissue until finally it may reach a point beneath the skin of the back. Here the larva matures and forms the well-known swelling or warble. In the spring of the year it works out through the skin. The next stage is spent in the ground. The pupa state lasts several weeks, when the mature fly issues forth.
The bot-fly of sheep (O. ovis) resembles an overgrown house-fly. Its general color is brown, and it is apparently lazy, flying about very little. This bot-fly makes its appearance when the warm weather begins, and deposits live larvae in the nostrils of sheep. This act is greatly feared by the animals, as shown by their crowding together and holding the head down. The larva works up the nasal cavities and reaches the sinuses of the head, where it becomes attached to the lining mucous membrane. In the spring, when fully developed, it passes out through the nasal cavities and nostrils, drops to the ground, buries itself, and in from four to six weeks develops into the mature fly.
SYMPTOMS OF BOT-FLY DISEASES.—The larvae of the bot-fly of the horse do not cause characteristic symptoms of disease. Work horses that are groomed daily are not hosts for a large number of "bots," but young and old horses that are kept in a pasture or lot and seldom groomed may become unthrifty and "pot bellied," or show symptoms of indigestion.
Cattle suffer much pain from the development of the larva of the H. lineata. During the spring of the year, the pain resulting from the presence of the larvae beneath the skin and the penetration of the skin is manifested by excitement and running about. Besides the loss in milk and beef production, there is a heavy yearly loss from the damage to hides.
The life of the bot-fly of sheep results in a severe catarrhal inflammation of the mucous membrane lining the sinuses of the head, and a discharge of a heavy, pus-like material from the nostrils. The irritation produced by the larvae may be so serious at times as to result in nervous symptoms and death.
Which of the following statements about cattle is supported by the passage?
They will lower their heads and group together when a bot-fly is near.
Bot-flies can cause them to stampede.
The bot-fly lays its eggs on their backs.
The bot-fly is attracted by their manure.
The bot-fly passes out through their nose.
Bot-flies can cause them to stampede.
When discussing the bot-fly laying eggs on an ox, the passage says that “On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded.” It is a somewhat common occurrence for cattle to start a stampede if a bot-fly lands on them and starts laying eggs.
Example Question #15 : Main Idea, Details, Opinions, And Arguments In Narrative Science Passages
Adapted from Common Diseases of Farm Animals by R. A. Craig (1916, 2nd ed.)
The common bot-fly of the horse (G. equi) has a heavy, hairy body. Its color is brown, with dark and yellowish spots. The female fly can be seen during the warm weather, hovering around the horse, and darting toward the animal for the purpose of depositing the egg. The color of the egg is yellow, and it adheres firmly to the hair. It hatches in from two to four weeks, and the larva reaches the mouth through the animal licking the part. From the mouth, it passes to the stomach, where it attaches itself to the gastric mucous membrane. Here it remains until fully developed, when it becomes detached and is passed out with the feces. The third stage is passed in the ground. This takes place in the spring and early summer and lasts for several weeks, when it finally emerges a mature fly.
The bot-fly of the ox (H. lineata) is dark in color and about the size of a honey-bee. On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded. The egg reaches the mouth through the animal licking the part. The saliva dissolves the shell of the egg and the larva is freed. It then migrates from the gullet, wanders about in the tissue until finally it may reach a point beneath the skin of the back. Here the larva matures and forms the well-known swelling or warble. In the spring of the year it works out through the skin. The next stage is spent in the ground. The pupa state lasts several weeks, when the mature fly issues forth.
The bot-fly of sheep (O. ovis) resembles an overgrown house-fly. Its general color is brown, and it is apparently lazy, flying about very little. This bot-fly makes its appearance when the warm weather begins, and deposits live larvae in the nostrils of sheep. This act is greatly feared by the animals, as shown by their crowding together and holding the head down. The larva works up the nasal cavities and reaches the sinuses of the head, where it becomes attached to the lining mucous membrane. In the spring, when fully developed, it passes out through the nasal cavities and nostrils, drops to the ground, buries itself, and in from four to six weeks develops into the mature fly.
SYMPTOMS OF BOT-FLY DISEASES.—The larvae of the bot-fly of the horse do not cause characteristic symptoms of disease. Work horses that are groomed daily are not hosts for a large number of "bots," but young and old horses that are kept in a pasture or lot and seldom groomed may become unthrifty and "pot bellied," or show symptoms of indigestion.
Cattle suffer much pain from the development of the larva of the H. lineata. During the spring of the year, the pain resulting from the presence of the larvae beneath the skin and the penetration of the skin is manifested by excitement and running about. Besides the loss in milk and beef production, there is a heavy yearly loss from the damage to hides.
The life of the bot-fly of sheep results in a severe catarrhal inflammation of the mucous membrane lining the sinuses of the head, and a discharge of a heavy, pus-like material from the nostrils. The irritation produced by the larvae may be so serious at times as to result in nervous symptoms and death.
One of the main points made in the last paragraph is that __________.
O. ovis is not unique to sheep
the larvae of O. ovis emerge as flies from the mouth of the sheep
bot-flies can cause sheeps' wool to become matted
the larvae of O. ovis cause an emission of pus from the nose of the sheep
the larvae of O. ovis can cause clotting and death in sheep
the larvae of O. ovis cause an emission of pus from the nose of the sheep
The author never states that O. ovis is found in other animals so we can assume that it is unique to sheep. The second line tells us that the larvae can cause “discharge of a heavy, pus-like material from the nostrils.” Which corresponds with the statement: “The larvae cause an emission of pus from the nose of the sheep.”
Example Question #2 : Content Of Natural Science Passages
Adapted from Common Diseases of Farm Animals by R. A. Craig (1916, 2nd ed.)
The common bot-fly of the horse (G. equi) has a heavy, hairy body. Its color is brown, with dark and yellowish spots. The female fly can be seen during the warm weather, hovering around the horse, and darting toward the animal for the purpose of depositing the egg. The color of the egg is yellow, and it adheres firmly to the hair. It hatches in from two to four weeks, and the larva reaches the mouth through the animal licking the part. From the mouth, it passes to the stomach, where it attaches itself to the gastric mucous membrane. Here it remains until fully developed, when it becomes detached and is passed out with the feces. The third stage is passed in the ground. This takes place in the spring and early summer and lasts for several weeks, when it finally emerges a mature fly.
The bot-fly of the ox (H. lineata) is dark in color and about the size of a honey-bee. On warm days, the female may be seen depositing eggs on the body of the animal, especially in the region of the heels. This seems to greatly annoy the animal, and it is not uncommon for cattle to become stampeded. The egg reaches the mouth through the animal licking the part. The saliva dissolves the shell of the egg and the larva is freed. It then migrates from the gullet, wanders about in the tissue until finally it may reach a point beneath the skin of the back. Here the larva matures and forms the well-known swelling or warble. In the spring of the year it works out through the skin. The next stage is spent in the ground. The pupa state lasts several weeks, when the mature fly issues forth.
The bot-fly of sheep (O. ovis) resembles an overgrown house-fly. Its general color is brown, and it is apparently lazy, flying about very little. This bot-fly makes its appearance when the warm weather begins, and deposits live larvae in the nostrils of sheep. This act is greatly feared by the animals, as shown by their crowding together and holding the head down. The larva works up the nasal cavities and reaches the sinuses of the head, where it becomes attached to the lining mucous membrane. In the spring, when fully developed, it passes out through the nasal cavities and nostrils, drops to the ground, buries itself, and in from four to six weeks develops into the mature fly.
SYMPTOMS OF BOT-FLY DISEASES.—The larvae of the bot-fly of the horse do not cause characteristic symptoms of disease. Work horses that are groomed daily are not hosts for a large number of "bots," but young and old horses that are kept in a pasture or lot and seldom groomed may become unthrifty and "pot bellied," or show symptoms of indigestion.
Cattle suffer much pain from the development of the larva of the H. lineata. During the spring of the year, the pain resulting from the presence of the larvae beneath the skin and the penetration of the skin is manifested by excitement and running about. Besides the loss in milk and beef production, there is a heavy yearly loss from the damage to hides.
The life of the bot-fly of sheep results in a severe catarrhal inflammation of the mucous membrane lining the sinuses of the head, and a discharge of a heavy, pus-like material from the nostrils. The irritation produced by the larvae may be so serious at times as to result in nervous symptoms and death.
Which of the following statements about bot-fly coloration is supported by the passage?
G. equi is black.
G. equi has some patterning.
O. ovis and H. linata both have coloured spots.
O. ovis is a different color than G. equi.
H. lineata is the same color as G. equi, but a different colour than O. ovis.
G. equi has some patterning.
The first paragraph contains the information that G. equi has “dark and yellowish spots,” which we can infer to be patterning. All of the other statements are misrepresentations of the information in the passage.
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