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"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 is most likely an excerpt from what type of document?
It most likely comes from a how-to manual, since it outlines the steps for planting and nurturing a cactus as it grows. A brochure would not contain quite as much information, and would not be detailed. A botanical garden would address the lineage of the plant and more about its genus and species, rather than how to grow it. A science textbook would explore the scientific analysis of the plant, such as how it obtains energy through photosynthesis and more facts along those lines. A personal anecdote about cacti would not need to give any information about how to grow one.
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"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.
Which of the following can be inferred from the information provided in the passage?
The second paragraph states that, unlike other plants, cacti produce CO2 during the day and O2 during the night, making them good plants to freshen the air when one is sleeping. Thus, it can be inferred that cacti have a unique respiration cycle, compared to other plants. The other answer choices are not inferences that can be made from the passage. The passage states that pot size is indeed a factor is growth, and the last paragraph mentions how it is easy to tell cacti apart from other plants. While the passage does mention that the cactus is a desert plant, nowhere does it say that cacti are found in EVERY desert. Similarly, the passage provides no information about for how long people have been growing cacti in their homes.
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"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 development of a new cactus from a graft is similar to what other biological phenomenon?
The passage discusses how grafting is a relatively simple procedure, and all that one must do is cut off a piece of the cactus and place it in an environment that supports its growth: the new cactus will develop roots. This is most similar to when a worm develops into a new organism when part of it is cut off. A lizard regrowing its tail is not similar to a graft, since the original organism simply regains the part that it lost. In the same vein, a cut that heals also involves an organism healing itself, not splitting apart to form a new organism. Birth from an egg or a failed organ transplant are not similar to the effects of a cactus graft.
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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 __________.
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.”
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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?
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.
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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”?
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.”
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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"?
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.
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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.
Based on the passage, which of the following can we infer would be the best reason for animals living in variable arctic environments to change their fur color?
If animals that live in arctic environments change their fur color, it is likely a seasonal change from brownish fur to predominantly white fur, as we’ve seen in the examples of the Irish hare, the stoat, and the weasel. What is specific about arctic environments? Thy likely involve a lot of snow, and are quite cold. Changing fur color to white would thus blend in with the snow and make an animal harder to see, as the last sentence suggests in saying that “in such an actively carnivorous creature as a stoat or weasel, \[color change\] is aggressive as well, rendering the animal inconspicuous to its prey.” we’re not told anything in the passage that would support the assertion that it would make the animal warmer, or that would support any of the other answer choices.
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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.
What can we infer preceded this paragraph?
In order to infer what likely “preceded,” or came before, this passage, we should take at what the passage is talking about right when it starts. The passage’s first sentence says, “The examples of protective resemblance so far quoted are mostly permanent adaptations to one particular sort of surrounding.” The “so far quoted” means so far said or provided and tells us that the writer has been talking about “examples of protective resemblance.” This means that the writer most likely discussed “animals that defend themselves by looking like things in a stable environment” in the part of the book that comes right before the passage.
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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.
Based on the passage, what can we infer about the weasel?
The weasel is mentioned in two places in the passage, both in the passage’s last paragraph, both reproduced here:
“But in winter, the entire coat \[of the stoat\], 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.”
What does the passage tell us about the weasel? Well, we can infer that it is in some way like the stoat, because the passage says “A similar example is afforded by the weasel” right after describing how the stoat’s fur changes color. We are also told that it is carnivorous, but this is not an inference we have to make, and it doesn’t relate to any of the answer choices. The best answer choice is “Like the stoat, it also changes its coat color.” This captures the specific similarity between the stoat and weasel being discussed when the author writes, “A similar example is afforded by the weasel.”
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Adapted from Cassell’s Natural History by Francis Martin Duncan (1913)
The penguins are a group of birds inhabiting the southern ocean, for the most part passing their lives in the icy waters of the Antarctic seas. Like the ratitae, penguins have lost the power of flight, but the wings are modified into swimming organs and the birds lead an aquatic existence and are scarcely seen on land except in the breeding season. They are curious-looking creatures that appear to have no legs, as the limbs are encased in the skin of the body and the large flat feet are set so far back that the birds waddle along on land in an upright position in a very ridiculous manner, carrying their long narrow flippers held out as if they were arms. When swimming, penguins use their wings as paddles while the feet are used for steering.
Penguins are usually gregarious—in the sea, they swim together in schools, and on land, assemble in great numbers in their rookeries. They are very methodical in their ways, and on leaving the water, the birds always follow well-defined tracks leading to the rookeries, marching with much solemnity one behind the other in soldierly order.
The largest species of penguins are the king penguin and the emperor penguin, the former being found in Kerguelen Land, the Falklands, and other southern islands, and the latter in Victoria Land and on the pack ice of the Antarctic seas. As they are unaccustomed from the isolation of their haunts to being hunted and persecuted by man, emperor penguins are remarkably fearless, and Antarctic explorers invading their territory have found themselves objects of curiosity rather than fear to the strange birds who followed them about as if they were much astonished at their appearance.
The emperor penguin lays but a single egg and breeds during the intense cold and darkness of the Antarctic winter. To prevent contact with the frozen snow, the bird places its egg upon its flat webbed feet and crouches down upon it so that it is well covered with the feathers. In spite of this precaution, many eggs do not hatch and the mortality amongst the young chicks is very great.
What can you infer is “the ratitae," underlined in the first paragraph?
The ratitae is mentioned in the paragraph’s first passage, when the author writes, “Like the ratitae, penguins have lost the power of flight, but the wings are modified into swimming organs and the birds lead an aquatic existence and are scarcely seen on land except in the breeding season.” In analyzing this, it’s important to ask: to what part of the sentence is “Like the ratitae” specifically referring? It is referring to the fact that “penguins have lost the power of flight.” Thus, the comparison being made here is that both the ratitae and the penguins “have lost the power of flight.” Therefore, we can infer that “the ratitae” is “a type of flightless bird.”
You may have picked out “a bird that lives in Antarctica” based on the information that precedes the comparison or “a bird that swims” based on the information that follows it. However, neither of these comparisons are being made in the passage: it is specifically the fact that both the ratitae and penguins “have lost the power of flight” that is being stated. Nothing in the passage suggests that “the ratitae” is “a bone found in most birds’ skeletons” or “a type of fish.”
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Adapted from Cassell’s Natural History by Francis Martin Duncan (1913)
The penguins are a group of birds inhabiting the southern ocean, for the most part passing their lives in the icy waters of the Antarctic seas. Like the ratitae, penguins have lost the power of flight, but the wings are modified into swimming organs and the birds lead an aquatic existence and are scarcely seen on land except in the breeding season. They are curious-looking creatures that appear to have no legs, as the limbs are encased in the skin of the body and the large flat feet are set so far back that the birds waddle along on land in an upright position in a very ridiculous manner, carrying their long narrow flippers held out as if they were arms. When swimming, penguins use their wings as paddles while the feet are used for steering.
Penguins are usually gregarious—in the sea, they swim together in schools, and on land, assemble in great numbers in their rookeries. They are very methodical in their ways, and on leaving the water, the birds always follow well-defined tracks leading to the rookeries, marching with much solemnity one behind the other in soldierly order.
The largest species of penguins are the king penguin and the emperor penguin, the former being found in Kerguelen Land, the Falklands, and other southern islands, and the latter in Victoria Land and on the pack ice of the Antarctic seas. As they are unaccustomed from the isolation of their haunts to being hunted and persecuted by man, emperor penguins are remarkably fearless, and Antarctic explorers invading their territory have found themselves objects of curiosity rather than fear to the strange birds who followed them about as if they were much astonished at their appearance.
The emperor penguin lays but a single egg and breeds during the intense cold and darkness of the Antarctic winter. To prevent contact with the frozen snow, the bird places its egg upon its flat webbed feet and crouches down upon it so that it is well covered with the feathers. In spite of this precaution, many eggs do not hatch and the mortality amongst the young chicks is very great.
We can infer from the passage that penguins probably eat __________ because the passage tells us that __________.
We can narrow down our answer choices by considering which of the options for the second blank the passage actually tells us. This allows us to eliminate the answer choices containing “penguins are carnivorous and hunt in groups” and “penguins are slow in the water.” Deciding between the remaining three answer choices, it doesn’t make sense that penguins would eat “polar bears” because they “are unafraid of explorers”—the second part of the answer may suggest that penguins are bold, and from this we might infer that penguins might try to fight and eat a polar bear, but it’s unlikely that would end well; the reverse is true. It is also doesn’t make sense that penguins would eat “microscopic sea creatures” because “the emperor penguin only lays one egg at a time”—these ideas are unrelated. This leaves us with the correct answer, the idea that penguins probably eat “fish” because “penguins live most of their lives in the water.” This makes sense; if penguins spend most of their lives in the water, they probably eat something that is found in the water, and fish are found in the water.
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Adapted from "Some Strange Nurseries" by Grant Allen in A Book of Natural History (1902, ed. David Starr Jordan)
Many different types of animals employ one of two strategies in raising their young. Certain animals, called “r-strategists,” turn out thousands of eggs with reckless profusion, but they let them look after themselves, or be devoured by enemies, as chance will have it. Other animals, called “K-strategists,” take greater pain in the rearing and upbringing of the young. Large broods indicate an “r” life strategy; small broods imply a “K” life strategy and more care in the nurture and education of the offspring. R-strategists produce eggs wholesale, on the off chance that some two or three among them may perhaps survive an infant mortality of ninety-nine per cent, so as to replace their parents. K-strategists produce half a dozen young, or less, but bring a large proportion of these on an average up to years of discretion.
Which of the following is suggested by the passage's wording?
Twice in the passage, when the author discusses r-strategists, he refers to them laying eggs. This first happens in the second sentence ("Certain animals, called 'r-strategists,' turn out thousands of eggs with reckless profusion"), and later in the fifth sentence ("R-strategists produce eggs wholesale"). Based on the author's wording, we can correctly assume that many r-strategists reproduce by laying eggs. None of the other answer choices are supported by the passage: nothing suggests that the author pursues biology as a hobby instead of a career; the fact that relative numbers of r-strategists and K-strategists are not discussed in the passage makes it impossible to assert that "most animals abandon their young to fend for themselves" or that "K-strategist animals are in short supply"; and nothing about environmental effects is discussed or suggested either, so "it would benefit the environment to ensure the survival of the entire brood of r-strategists" cannot be the correct answer either.
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Adapted from "Birds’ Nests" by John Burroughs in A Book of Natural History (1902, ed. David Starr Jordan)
The rarest of all nests is that of the eagle, because the eagle is the rarest of all birds. Indeed, so seldom is the eagle seen, that its presence always seems accidental. It appears as if merely pausing on the way, while bound for some distant unknown region. One September, while a youth, I saw the ring-tailed eagle, an immense bird, the sight of which filled me with awe. It lingered about the hills for two days. Some young cattle, a two year-old colt, and half a dozen sheep were at pasture on a high ridge that led up to the mountain, and in plain view of the house. On the second day, this dusky monarch was seen flying about above them. Presently he began to hover over them, after the manner of a hawk watching for mice. He then with extended legs let himself slowly down upon them, actually grappling the backs of the young cattle, and frightening the creatures so that they rushed about the field in great consternation; and finally, as he grew bolder and more frequent in his descents, the whole herd broke over the fence, and came tearing down to the house “like mad.” It did not seem to be an assault with intent to kill, but was, perhaps, a stratagem resorted to in order to separate the herd and expose the lambs, which hugged the cattle very closely. When he occasionally alighted upon the oaks that stood near, the branch could be seen to sway and bend beneath him. Finally, as a rifleman started out in pursuit of him, he launched into the air, set his wings, and sailed away southward. A few years afterward, in January, another eagle passed through the same locality, alighting in a field near some dead animal, but tarried briefly.
What can you most reasonably infer about the author?
You can reasonably infer that the author is “an avid bird watcher.” This is because he seems familiar with the specific type of eagles that he has observed, and also because he is out and about wandering around frequently enough to observe and carefully track two eagles. He also seems to know, from experience, that eagles are the rarest of all birds. There is nothing to suggest he is “not religious,” or is writing for the first time. Its possible he is “a natural woodsman,” but requires a great deal more inference than the correct answer. The idea that he has a “fear of riflemen” is not supported by the text.
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Adapted from "The Man-Like Apes" by T. H. Huxley in A Book of Natural History (1902, ed. David Starr Jordan)
The orangutan is found only in Sumatra and Borneo, and is common in either of these islands—in both of which it occurs always in low, flat plains, never in the mountains. It loves the densest and most sombre of the forests, which extend from the seashore inland, and thus is found only in the eastern half of Sumatra, where alone such forests occur, though, occasionally, it strays over to the western side. On the other hand, it is generally distributed through Borneo, except in the mountains, or where the population is dense. In favorable places the hunter may, by good fortune, see three or four in a day.
Except in the pairing time, the old males usually live by themselves. The old females and the immature males, on the other hand, are often met with in twos and threes, and the former occasionally have young with them, though the pregnant females usually separate themselves, and sometimes remain apart after they have given birth to their offspring. The young orangs seem to remain unusually long under their mother’s protection, probably in consequence of their slow growth. While climbing, the mother always carries her young against her bosom, the young holding on by the mother’s hair. At what time of life the orangutan becomes capable of propagation, and how long the females go with young is unknown, but it is probable that they are not adult until they arrive at ten or fifteen years of age. A female which lived for five years at Batavia had not attained one-third the height of the wild females. It is probable that, after reaching adult years, they go on growing, though slowly, and that they live to forty or fifty years. The Dyaks tell of old orangs that have not only lost all their teeth, but which find it so troublesome to climb that they maintain themselves on windfalls and juicy herbage.
The “Dyaks” are most probably __________.
In context, the author says “The Dyaks tell of old orangs that have not only lost all their teeth, but which find it so troublesome to climb that they maintain themselves on windfalls and juicy herbage.” The excerpt suggests that some people, called the “Dyaks,” have some sort of lengthy experience and knowledge of the behavior and lifetimes of orangutans, suggesting deep familiarity with these creatures. From this you can infer that “Dyaks” are most probably “indigenous people of Borneo or Sumatra.” And, indeed, this is a name given to a group of indigenous people from Borneo.
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Adapted from "Birds’ Nests" by John Burroughs in A Book of Natural History (1902, ed. David Starr Jordan)
The woodpeckers all build in about the same manner, excavating the trunk or branch of a decayed tree, and depositing the eggs on the fine fragments of wood at the bottom of the cavity. Though the nest is not especially an artistic work, requiring strength rather than skill, yet the eggs and the young of few other birds are so completely housed from the elements, or protected from their natural enemies—the jays, crows, hawks, and owls. A tree with a natural cavity is never selected, but one which has been dead just long enough to have become soft and brittle throughout. The bird goes in horizontally for a few inches, making a hole perfectly round and smooth and adapted to his size, then turns downward, gradually enlarging the hole, as he proceeds, to the depth of ten, fifteen, twenty inches, according to the softness of the tree and the urgency of the mother bird to deposit her eggs. While excavating, male and female work alternately. After one has been engaged fifteen or twenty minutes, drilling and carrying out chips, it ascends to an upper limb, utters a loud call or two, when its mate soon appears, and, alighting near it on the branch, the pair chatter and caress a moment; then the fresh one enters the cavity and the other flies away.
What can you infer about male and female woodpeckers from this passage?
In the concluding lines of this passage, the author talks about how “while excavating, male and female work alternately.” He also says, “the pair chatter and caress a moment; then the fresh one enters the cavity and the other flies away.” The key word for answering this question is “caress.” It means touch and stroke with affection. From the sum of this information, you can reasonably infer that woodpeckers “have a close and intimate bond.”
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Adapted from "How Animals Spend the Winter" by W. S. Blatchley in A Book of Natural History (1902, ed. David Starr Jordan)
One of the greatest problems that each of the living forms about us has had to solve, during the years of its existence on earth, is how best to perpetuate its kind during that cold season that once each year, in our temperate zone, is bound to come. Many are the solutions to this problem. Each form of life has, as it were, solved it best to suit its own peculiar case, and to the earnest student of Nature there is nothing more interesting than to pry into these solutions and note how varied, strange, and wonderful they are.
To fully appreciate some of the facts mentioned below it must be borne in mind that there is no such thing as “spontaneous generation” of life. Every cell is the offspring of a pre-existing cell. Hence every weed that next season will spring up and provoke the farmer’s ire, and every insect that will then make life almost intolerable for man or beast, exists throughout the winter in some form.
Beginning with the earthworms and their kindred, we find that at the approach of winter they burrow deep down where the icy breath of the frost never reaches, and there they live, during the cold season, a life of comparative quiet. That they are exceedingly sensitive to warmth, however, may be proven by the fact that when a warm rain comes some night in February or March, thawing out the crust of the earth, the next morning reveals in our dooryards the mouths of hundreds of the pits or burrows of these primitive tillers of the soil, each surrounded by a little pile of pellets, the castings of the active artisans of the pits during the night before.
If we will get up before dawn on such a morning we can find the worms crawling actively about over the surface of the ground, but when the first signs of day appear they seek once more their protective burrows, and only an occasional belated individual serves as a breakfast for the early birds.
Which of these can you most reasonably infer about this passage?
It is very difficult to make any inferences of these kinds from this passage. Although the author talks about earthworms a lot, there is nothing to suggest he could be described as a “dedicated lover of earthworms.” There is also no evidence to suggest this was written in another language, nor by an American. However, there is one small piece of evidence that tells you this is almost certainly part of a longer passage about the same subject. When transitioning from the manner in which animals are able to survive the winter to a specific example of the earthworm, the author suggests that the earthworm is going to be the first of many examples. He says “Beginning with the earthworms and their kindred." The key word here is “beginning.” If he were just to talk about earthworms it would become a redundant phrase, and because in this excerpt he only talks about earthworms, we can infer this is part of a longer passage. The idea that it is part of a debate about the nature of life requires further inference because although the essay is somewhat persuasive in nature, it does not specifically refute any points.
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Adapted from "The Greatest Sea-Wave Ever Known" by R. A. Proctor in Wonders of Earth, Sea, and Sky (1902, ed. Edward Singleton Holden)
It was at Arequipa, at the foot of the lofty volcanic mountain Misti, that the most terrible effects of the great earthquake were experienced. Within historic times, Misti has poured forth no lava streams, but that the volcano is not extinct is clearly evidenced by the fact that in 1542 an enormous mass of dust and ashes was vomited forth from its crater. On August 13th, 1868, Misti showed no signs of being disturbed. So far as the volcanic neighbor was concerned, the forty-four thousand inhabitants of Arequipa had no reason to anticipate the catastrophe which presently befell them.
At five minutes past five, an earthquake shock was experienced, which, though severe, seems to have worked little mischief. Half a minute later, however, a terrible noise was heard beneath the earth; a second shock more violent than the first was felt, and then began a swaying motion, gradually increasing in intensity. In the course of the first minute, this motion had become so violent that the inhabitants ran in terror out of their houses into the streets and squares. In the next two minutes, the swaying movement had so increased that the more lightly built houses were cast to the ground, and the flying people could scarcely keep their feet. "And now," says Von Tschudi, "there followed during two or three minutes a terrible scene. The swaying motion changed into fierce vertical upheaval. The subterranean roaring increased in the most terrifying manner; then were heard the heart-piercing shrieks of the wretched people, the bursting of walls, the crashing fall of houses and churches, while over all rolled thick clouds of a yellowish-black dust, which, had they been poured forth many minutes longer, would have suffocated thousands." Although the shocks had lasted but a few minutes, the whole town was destroyed. Not one building remained uninjured, and there were few that did not lie in shapeless heaps of ruins.
What can be reasonably inferred about Von Tschudi?
When describing the immediate effects and impact of the volcanic eruption, the author of this passage turns to Von Tschudi’s description of events. This should suggest to us two things: firstly, that the author is not an expert on the situation and is writing about this eruption as an introduction to something else. Also, and more importantly, it should suggest that Von Tschudi is “considered an expert on the disaster at Arequipa.” If his analysis is being quoted in another scholarly paper, he must be thought of as an expert. It might be reasonably to infer, from Von Tschudi’s thorough description, that he was living in Arequipa at the time or was born and raised there; however, there is insufficient evidence to reliably determine this. Answering with these two answers requires a good deal more inference than the correct answer.
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Adapted from “Comets” by Camille Flammarion in Wonders of Earth, Sea, and Sky (1902, ed. Edward Singleton Holden)
The history of a comet would be an instructive episode of the great history of the heavens. In it could be brought together the description of the progressive movement of human thought, as well as the astronomical theory of these extraordinary bodies. Let us take, for example, one of the most memorable and best-known comets, and give an outline of its successive passages near the Earth. Like the planetary worlds, comets belong to the solar system, and are subject to the rule of the Star King. It is the universal law of gravitation which guides their path; solar attraction governs them, as it governs the movement of the planets and the small satellites. The chief point of difference between them and the planets is that their orbits are very elongated, and instead of being nearly circular, they take the elliptical form. In consequence of the nature of these orbits, the same comet may approach very near the sun, and afterwards travel from it to immense distances.
Thus, the period of the Comet of 1680 has been estimated at three thousand years. It approaches the sun, so as to be nearer to it than our moon is to us, whilst it recedes to a distance 853 times greater than the distance of the Earth from the sun. On the 17th of December, 1680, it was at its perihelion—that is, at its greatest proximity to the sun; it is now continuing its path beyond the Neptunian orbit. Its velocity varies according to its distance from the solar body. At its perihelion it travels thousands of leagues per minute; at its aphelion it does not pass over more than a few yards.
Its proximity to the Sun in its passage near that body caused Newton to think that it received a heat twenty-eight thousand times greater than that we experience at the summer solstice, and that this heat being two thousand times greater than that of red-hot iron, an iron globe of the same dimensions would be fifty thousand years entirely losing its heat. Newton added that in the end, comets will approach so near the sun that they will not be able to escape the preponderance of its attraction, and that they will fall one after the other into this brilliant body, thus keeping up the heat which it perpetually pours out into space. Such is the deplorable end assigned to comets by the author of the Principia, an end which makes De la Brétonne say to Rétif: "An immense comet, already larger than Jupiter, was again increased in its path by being blended with six other dying comets. Thus displaced from its ordinary route by these slight shocks, it did not pursue its true elliptical orbit; so that the unfortunate thing was precipitated into the devouring centre of the Sun." "It is said," added he, "that the poor comet, thus burned alive, sent forth dreadful cries!"
Who can you infer is the author of Principia?
Contextual clues in the third paragraph should help you determine that the author of the Principia is “Newton.” The author of this passage says “Such is the deplorable end assigned to comets by the author of the Principia," and he says this immediately after a long discussion of the research and conclusions reached by Newton on the demise of the very large comet under discussion throughout the passage. The key here is to identify the correct clues, and ignore the confusing mention of “De la Brétonne” and “Rétif” immediately after the mention of the Principia.
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Adapted from A Catechism of Familiar Things: Their History and the Events Which Led to Their Discovery by the Benziger Brothers (1881)
Potatoes grew wild in Peru, a country of South America, from where they were transplanted to other parts of the American continent, and afterwards to Europe. The honor of introducing this useful vegetable into England is divided between Sir Francis Drake, in 1580, and Sir Walter Raleigh, in 1586, some crediting it to the former, and others to the latter. It is certain they were obtained from Virginia in the time of Raleigh; they were grown only in the gardens of the nobility, and were considered a great delicacy. They now constitute a crucial article of food in most of the countries of Europe and America; in Ireland, they have long furnished nearly four-fifths of the entire food of the people.
What might we determine about the significance of the potato in Irish history?
Many of these answer choices are in fact true, but only one is supported by the information included in this passage. The correct answer is that the potato “fed a large percentage of the population for a long time.” This is shown by the author when he says, “in Ireland, they have long furnished nearly four-fifths of the entire food of the people.” “Furnished,” in this context, means provided for.
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