Solution & Explanation for TOEFL iBT Reading Practice Test 21 from Delta’s Key to the Next Generation TOEFL Test – Six Practice Tests for the iBT by Nancy Gallagher
1. B The passage does not state that an unbroken prairie now exte
2. B During the last century, large parts of the prairie have been converted to agricultural use. Clues: One hundred years ago, the Great Plains grasslands were one vast, unbroken prairie. Much of the prairie is now farmland…. (1.1)
3. D Alien means imported in this context. Clues:…virtually all the major native grasses have been replaced by alien species. Imported grasses have replaced the original, native grasses. (1.4)
4. B The prairie potholes owe their origins mainly to the glaciers that melted at the end of the last Ice Age. Clues: They were formed during the most recent Ice Age…. When the Ice Age ended around ago, the retreating glaciers created about 25 million depressions…. (1.1)
5. D Today these small wetlands still cover the prairies…is paraphrased in …the small ponds remain; …although much of the landscape… has been transformed to cropland and grassland for grazing is paraphrased in Even though a large portion of the prairies is used for crops and grazing…. (1.7)
6. A Dot means cover in this context. Clues: Today these small wetlands still cover the prairies…; …the seasonal wetlands that dot portions of Minnesota, Iowa…. (1.4)
7. B The author’s purpose is to emphasize the area’s value as a breeding ground for ducks. Clues: …serves as an important breeding area for more than 500 bird species, including large numbers of migrating shorebirds and waterfowl; Every spring, birds arrive in great numbers…to mate in the seasonal wetlands…; Prairie pothole country produces half of North America ‘s 35 to 40million ducks. …(1.6)
8. D A carbon sink removes carbon dioxide naturally from the atmosphere. Clue: …a vast carbon sink: a natural sponge that absorbs carbon dioxide emissions from cars, factories, and power plants.(1.1)
9. C The referent of this is something that scientists have termed “carbon sequestration.” The previous sentence states that carbon dioxide is captured naturally and stored in trees, soil, and plants. Logic tells you that this refers to the capture and storage of carbon dioxide in trees, soil, and plants. (1.3)
10. A You can infer that carbon sequestration in the prairie pothole region depends on the land not being disturbed by agriculture. Clues: …prairie potholes hold an average of 2.5 tons of carbon per acre per year when not being farmed;…if the entire pothole region in the United States and Canada were to stop being farmed, the region would store about 400 million tons of carbon over 10 years…. (1.5)
11. C Offset means counteract in this context. Clues: …the region would store about 400 million tons of carbon over 10 years—the equivalent of taking almost 4 million cars off the road. Thus, preserving the potholes could be a way to offset greenhouse gas emissions that are warming the planet. The prefix counter- = against; preserving the potholes would act against greenhouse gases such as carbon dioxide. (1.4)
12. A In the added sentence, Today is a time expression that logically follows One hundred years ago in the previous sentence. In the added sentence, however is a transition that shows contrast between the Great Plains grasslands were one vast, unbroken prairie in the previous sentence and the original grassland associations of plants and animals have been almost completely destroyed in the added sentence. (1.8)
13. B, C, E Key information: Much of the prairie is now farmland…dominated by monocultures of cereal grains; In areas given over to grazing lands…virtually all the major native grasses have been replaced by alien species; An important feature of the northern Great Plains grasslands is the presence of millions of glacial depressions that are now small ponds known as prairie potholes; …serves as an important breeding area for more than 300 bird species…; … the prairie pothole region is potentially a vast carbon sink…. Answer (A) is not mentioned; answers (D) and (F) are minor ideas. (1.9)
14. B The author makes the point that monarchs did not have real power but were symbols of national unity. Clues: …while monarchs remained symbols of national unity, real power had passed to constitutional assemblies. (1.1)
15. A Survived means remained in this context. Clues: At the start of the twentieth century, monarchs ruled over most of the world, but by the middle of the century, only a handful remained; …while monarchs remained symbols of national unity…; It lasted longer in the few small states…; the stem -vzv- = alive. (1.4)
16. B The referent of The term is something that applies to a broad group of states with a parliamentary or representative political tradition. The subject of the previous sentence is liberal democracy. Logic tells you that The term refers to liberal democracy. (1.3)
17. A The author’s purpose is to contrast two concepts of where political authority rests. In liberal democracies, political authority rests in the people acting through elected representatives. In people’s democracies, political authority rests in the Communist party. Clues: Liberal democracies differ from… in which the Communist party holds the ultimate authority. (1.6)
18. C Pattern means model in this context. Clues: …some form of liberal democracy…; …with the executive power vested in a cabinet responsible to the parliament…. The passage describes various forms or models of democracies: people’s democracies, parliamentary democracies, and presidential democracies. (1.4)
19. D The passage mentions a bill of rights stated in a constitution as a limit on state control. Clues: The liberal democratic state claimed the right to control every aspect of human life…except where limits on state control were directly stated in a bill of rights in a democratic constitution…. (1.1)
20. D Every democratic state changed during the twentieth century in the way that state activity expanded to promote the well being of the people. Clues: The expansion of state activity and extension of state services involved a new view of legislation and its role in society. The passing of laws came to be seen as a way to promote the well being of the people.(1.1)
21. C In these cases, some form of totalitarian dictatorship emerged… is paraphrased in Totalitarian dictatorships took over some democracies…;… replacing popular sovereignty with the total power of the state is paraphrased in … took over some democracies with the idea that the state, not the people, held all power. (1.7)
22. B The authority of the people through elected representatives is not a characteristic of authoritarian governments; it is a characteristic of liberal democracies. All of the other answers are given: …a system that prohibited parties opposed to the regime…; …a head of state or leader with exceptional powers…;… a bureaucratic administration that was in no way subject to popular control. (1.2)
23. A You can infer that the author believes there was a general movement away from monarchy toward democracy, with some cases of authoritarian rule. Clues: In most states where monarchical authority was removed, some form of liberal democracy took its place; The trend toward liberal democracy continued throughout the century, but at various times there was also a tendency toward a revival of authoritarian rule. (1.5)
24. D In the added sentence, for example is a transition that introduces the example of the British Parliament passing more laws in the first half of the twentieth century than in all its previous history. This example develops the idea that the number of new laws increased immensely, mentioned in the previous sentence. (1.8)
25. A, E Monarchy: …a monarch, whose right to rule is generally hereditary and lifelong; Monarchy survived as a form in Europe only where the king or queen functioned as the symbolic head of a parliamentary state….
B, F Liberal Democracy: …an elected executive is responsible to the will of the people as a whole; The doctrine that all of the people had effective authority, or sovereignty, became the basis for the functioning of democratic states. This doctrine of popular sovereignty….
D Dictatorship: …some form of totalitarian dictatorship emerged, replacing popular sovereignty with the total power of the state;
…a head of state or leader with exceptional powers, with a party to support him. Answers (C) and (G) are not mentioned. (1.10)
26. B The author’s purpose is to emphasize the close connection between smell and the brain. Clues:
Smell is the most direct of all the senses; The olfactory nerve, which manages the perception of smells, is essentially an extension of the brain; …a direct link from receptors at the top of the nose to the portion of the brain…. (1.6)
27. A Detects means notices in this context. Clues: ..receptors at the top of the nose…; …olfactory system detects certain airborne chemicals that enter the nose…; …chemical information…. The prefix de- = from. The olfactory system notices information from chemicals that enter the nose. (1.4)
28. D The color of the olfactory region at the upper end of each nostril shows the strength of the ability to smell. Clues: The shade of yellow indicates the strength of the sense of smell…; Animals have a very strong sense of smell, so their olfactory regions are dark yellow to reddish brown…. (1.1)
29. B Diffuse means flow in this context. Clues: When an odorous substance enters the nose…; Odor molecules diffuse into this region…; …odor molecules float up into the nasal cavity…. (1.4)
30. C When the cilia of the olfactory receptor cells absorb odor molecules, the olfactory nerve sends impulses to the brain. Clues: Odor molecules diffuse into this region and are absorbed by the cilia of the olfactory receptor cells; The receptor cells alert the olfactory nerve, which sends impulses to the brain s olfactory bulb, or smell center. (1.1)
31. B Integrates means connects in this context. Clues: The limbic system of the brain integrates memory, emotion, and behavior; …a group of related….
The prefix inte-/inter- = between. The paragraph discusses how the brain makes connections between memory, emotion, and behavior. (1.4)
32. B The passage does not state that the scent is transmitted to the other sensory organs. All of the other answers are given: When we inhale a scent, receptors in the brain s limbic center compare the odor entering our nose to odors stored in our memory; …memories associated with those odors are stimulated;…it triggers powerful images and emotions. (1.2)
33. A The author’s purpose is to give examples of smells that can trigger memories and emotions. The smells of crayons and grass can call up memories of childhood. Clues: A smell can be overwhelmingly nostalgic because it triggers powerful images and
34. C What we see and hear may fade quickly in short-term memory… is paraphrased in …while sights and sounds may be held only briefly; … but what we smell is sent directly to long-term memory is paraphrased in Smells go straight to long-term memory…. (1.7)
35. C The referent of which is something that was presented both with and without scents. The sentence discusses a study in which children memorized a word list. Logic tells you that which refers to list. (1.3)
36. B You can infer that scents can strengthen the ability to hold new information in the memory. Clues:
Smells can…stimulate learning and retention; The children recalled words on the list more easily and with higher accuracy when the list was given with scents than without…. (1.5)
37. A In the added sentence, One of these structures refers to a group of related nervous system structures, mentioned in the previous sentence. The added sentence gives the example of central processing unit to develop the idea of a group of related nervous system structures. (1.8)
38. B, C, F Key information: The olfactory nerve provides a direct link from receptors at the top of the nose to the portion of the brain that controls memory, emotion, and behavior; The limbic system of the brain integrates memory, emotion…; …receptors in the brains limbic center compare the odor entering our nose to odors stored in our memory; …memories associated with those odors are stimulated.
Scent may be the strongest trigger of memory and emotions; Smells can increase alertness and stimulate learning and retention. Answers (A), (D) and (E) are minor ideas. (1.9)
39. A Maliciously means destructively in this context.
Clues: …sometimes maliciously but usually with results that are positive. But shows contrast, indicating that maliciously is the opposite of with results that are positive. The prefix mal- = bad. (1.4)
40. D When he plays tricks, he performs important cultural tasks that benefit humans… is paraphrased in …his tricks contribute positively to human culture; .. for this reason the trickster is a significant figure in world mythology is paraphrased in The trickster is an important mythological character because…. (1.7)
41. A The author’s purpose is to illustrate two different views of the trickster-hero. Clues: In different cultures, the trickster and the hero are combined in various ways. In Greek mythology…usually portrayed as an intellectual. In many Native American stories… usually more of a jokester or a prankster than an intellectual. (1.6)
42. C Pranks means mischievous acts in this context.
Clues: …one who tricks others…; …trickster…; …acts out ofpassion and impulse; …behavior…. (1.4)
43. C The referent of both is something for which the trickster is responsible. The sentence discusses good and evil. Logic tells you that both refers to good and evil. (1.3)
44. D Awareness of good and evil is not a trait of the trickster; in fact, the trickster knows neither good nor evil. All of the other answers are given: …the trickster is a god, spirit, human, or animal who breaks the rules…;…occasionally disguises himself in female form; …the greatest shapeshifter of all and can change into anything…; …superior to man because of his superhuman qualities…; …possesses some magical powers. (1.2)
45. B Native American stories with a trickster-hero are usually about the creation or transformation of the world. Clue: In Native American mythology, the majority of trickster myths concern the creation or transformation of the earth. (1.1)
46. C In the story about Raven, the trickster steals the sun from the gods. Clues: Raven knows the gods are protective of their possessions, so he devises a trick; .. .flies off carrying the ball of light in his beak. He hangs the ball—the sun—in the sky, bringing light to the world. (1.1)
47. B Savior means one who rescues others from harm in this context. Clues: …leads the human race to a new and better world; …whose great gift to humans is showing them new ways of knowing and doing. Savior is a noun form of the verb save. (1.4)
48. C You can infer that the author believes the trickster serves as an explanation for creation, change and renewal. Clues: …the majority of trickster myths concern the creation or transformation of the earth;
… there is darkness at the beginning of the world, so Raven decides he will find light; …the trickster is a savior whose great gift to humans is showing them new ways of knowing and doing. (1.5)
49. A The added sentence compares Raven and Coyote, developing the idea that Coyote s character is similar to that of Raven s, mentioned in the previous sentence. The added sentence introduces the idea of events that benefit humanity, which the next sentence develops with the example Coyote steals fire from a group of “fire beings ” and gives it to humans. (1.8)
50. B, E, G Raven: Raven is the greatest shapeshifter of all and can change into anything to get what he wants; …watches each day as the chief god’s daughter draws water from a nearby lake. He magically transforms himself into a pinyon seed and falls into the girl s drinking cup; … tricks the elder gods into revealing where they hide a shining ball of light; He hangs the ball—the sun—in the sky, bringing light to the world.
A, F Coyote: … Coyote wants to make human life more interesting, so he introduces sickness, sorrow, and death; …by causing the flood, Coyote leads the human race to a new and better world. Answers (C) and (D) describe neither Raven nor Coyote. (1.10)
51. C Furnished means provided in this context. Clues: …by providing meat, milk, and fertilizer…;… main source of animal protein…; …also furnished wool, leather, and land transport. (1.4)
52. C Small animals do not have the ability to pull a plow.
Clues: …livestock helped to feed more people…by pulling plows; … they also furnished wool, leather, and land transport; Many of these small animals provided food, clothing, or warmth. However, none of them pulled plows… none carried riders…. (1.1)
53. A You can infer that relatively few species of large mammals have the necessary characteristics for domestication. Clues: Humans have domesticated only a few species of large animals…; Early herding societies quickly domesticated all large mammal species that were suitable for domestication. (1.5)
54. D Early humans domesticated all suitable large mammal species within a few thousand years after farming and herding began. Clues: Early herding societies quickly domesticated all large mammal species that were suitable for domestication; … these species were domesticated.. .within the first few thousand years of the origins of farming-herding societies…. (1.1)
55. C Domesticated animals differ from their wild ancestors because animals’ evolutionary responses in captivity differ from those in the wild. Clues:
Truly domesticated animals differ in many ways from their wild ancestors. These differences result from.. .evolutionary responses of animals to the forces of natural selection operating in human environments rather than in wild environments. (1.1)
56. B A candidate for domestication must be primarily a herbivore… is paraphrased in Herbivorous animals are likely to be domesticated…; …because it takes less plant biomass to feed a plant eater than it does to feed a carnivore that consumes plant eaters is paraphrased in …because they eat less plant matter than what carnivores consume indirectly. (1.1)
57. D The author’s purpose is to give examples of animals that grow too slowly for domestication. Clues: A candidate must…also grow quickly. That eliminates gorillas and elephants…. (1.6)
58. C Disqualify means reject in this context. Clues: …certain qualities disqualify a wild animal for domestication; …cannot have…; …characteristics that eliminate…. The paragraph discusses characteristics that are not desirable for domestication; any of these qualities would reject an animal for domestication. (1.4)
59. A Panics means feels terror in this context. Clues:
The animal cannot be so nervous…; …react to danger from predators or humans…; …programmed for instant flight when they perceive danger. (1.4)
60. D You can infer that deer and antelope have not successfully been domesticated. Clues: The animal cannot be so nervous that it panics around humans; Some species are nervous, fast, and programmed for instant flight when they perceive danger; Most species of deer and antelope are of the former type…. (1.5)
61. B Unpredictable behavior is not a characteristic favorable to domestication. In fact, it is a quality that would disqualify an animal for domestication. All of the other answers are given: A candidate must not only weigh an average of over 100 pounds but also grow quickly;… candidates for domestication must be able to breed successfully in captivity;… living in a herd, maintaining a dominance hierarchy in the herd…. (1.2)
62. C The added sentence gives more information about
Eurasia, mentioned in the previous sentence. The added sentence introduces the idea of Eurasia having a great many large mammal species, which the next sentence develops further. (1.8)
63. A, D, E Key information: Large domestic animals became the societies’ main source of animal protein…; Early herding societies quickly domesticated all large mammal species that were suitable for domestication; To be domesticated, a wild species must possess several characteristics. A candidate for domestication must be primarily a herbivore…; Almost all domesticated large mammals are species whose wild ancestors share three social characteristics: living in a herd…. Answers (B) and (F) are minor ideas; answer (C) is not mentioned. (1.9)