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Navajo Art

The Navajo, a Native American people living in the southwestern United States, live in small scattered settlements. In many respects, such as education, occupation, and leisure activities, their life is like that of other groups that contribute to the diverse social fabric of North American culture in the twenty-first century. At the same time, they have retained some traditional cultural practices that are associated with particular art forms. For example, the most important traditional Navajo rituals include the production of large floor paintings. These are actually made by pouring thin, finely controlled streams of colored sands or pulverized vegetable and mineral substances, pollen, and flowers in precise patterns on the ground. The largest of these paintings may be up to 5.5 meters in diameter and cover the entire floor of a room. Working from the inside of the design outward, the Navajo artist and his assistants will sift the black, white, bluish-gray, orange, and red materials through their fingers to create the finely detailed imagery. The paintings and chants used in the ceremonies are directed by well-trained artists and singers who enlist the aid of spirits who are impersonated by masked performers. The twenty-four known Navajo chants can be represented by up to 500 sand paintings. These complex paintings serve as memory aids to guide the singers during the performance of the ritual songs, which can last up to nine days.

The purpose and meaning of the sand paintings can be explained by examining one of the most basic ideals of Navajo society, embodied in their word hozho (beauty or harmony, goodness, and happiness). It coexists with hochxo ("ugliness," or "evil," and "disorder") in a world where opposing forces of dynamism and stability create constant change. When the world, which was created in beauty, becomes ugly and disorderly, the Navajo gather to perform rituals with songs and make sand paintings to restore beauty and harmony to the world. Some illness is itself regarded as a type of disharmony. Thus, the restoration of harmony through a ceremony can be part of a curing process.

Men make sand paintings that are accurate copies of paintings from the past. The songs sung over the paintings are also faithful renditions of songs from the past. By recreating these arts, which reflect the original beauty of creation, the Navajo bring beauty to the present world. As relative newcomers to the Southwest, a place where their climate, neighbors, and rulers could be equally inhospitable, the Navajo created these art forms to affect the world around them, not just through the recounting of the actions symbolized, but through the beauty and harmony of the artworks themselves. The paintings generally illustrate ideas and events from the life of a mythical hero, who, after being healed by the gods, gave gifts of songs and paintings. Working from memory, the artists re-create the traditional form of the image as accurately as possible.

The Navajo are also world-famous for the designs on their woven blankets. Navajo women own the family flocks, control the shearing of the sheep, the carding, the spinning, and dying of the thread, and the weaving of the fabrics. While the men who make faithful copies of sand paintings from the past represent the principle of stability in Navajo thought, women embody dynamism and create new designs for every weaving they make. Weaving is a paradigm of the creativity of a mythic ancestor named Spider Woman who wove the universe as a cosmic web that united earth and sky. It was she who，according to legend, taught Navajo women how to weave. As they prepare their materials and weave. Navajo women imitate the transformations that originally created the world. Working on their looms, Navajo weavers create images through which they experience harmony with nature. It is their means of creating beauty and thereby contributing to the beauty, harmony,and healing of the world. Thus, weaving is a way of seeing the world and being part of it.

Paragraph 1

The Navajo, a Native American people living in the southwestern United States, live in small scattered settlements. In many respects, such as education, occupation, and leisure activities, their life is like that of other groups that contribute to the diverse social fabric of North American culture in the twenty-first century. At the same time, they have retained some traditional cultural practices that are associated with particular art forms. For example, the most important traditional Navajo rituals include the production of large floor paintings. These are actually made by pouring thin, finely controlled streams of colored sands or pulverized vegetable and mineral substances, pollen, and flowers in precise patterns on the ground. The largest of these paintings may be up to 5.5 meters in diameter and cover the entire floor of a room. Working from the inside of the design outward, the Navajo artist and his assistants will sift the black, white, bluish-gray, orange, and red materials through their fingers to create the finely detailed imagery.The paintings and chants used in the ceremonies are directed by well-trained artists and singers who enlist the aid of spirits who are impersonated by masked performers. The twenty-four known Navajo chants can be represented by up to 500 sand paintings. These complex paintings serve as memory aids to guide the singers during the performance of the ritual songs, which can last up to nine days.

1. The word “precise” is closest in meaning to

A. colorful

B. exact

C. delicate

D. complex

2. The word “enlist" in the passage is closest in meaning to

A. assist

B. require

C. describe

D. recruit

3. What can be inferred from paragraph 1 about the Navajo ritual chants?

A. There is a large number of them.

B. Each of them corresponds to a particular sand painting.

C. They are difficult to remember.

D. They do not take long to perform

4. According to paragraph 1, all of the following are true of many important Navajo rituals EXCEPT:

A. They involve the creation of large, detailed images.

B. They include performers whose faces are covered.

C. They take place indoors.

D. They are performed without elaborate planning.

Paragraph 2

The purpose and meaning of the sand paintings can be explained by examining one of the most basic ideals of Navajo society, embodied in their word hozho (beauty or harmony, goodness, and happiness). It coexists with hochxo ("ugliness," or "evil," and "disorder") in a world where opposing forces of dynamism and stability create constant change. When the world, which was created in beauty, becomes ugly and disorderly, the Navajo gather to perform rituals with songs and make sand paintings to restore beauty and harmony to the world. Some illness is itself regarded as a type of disharmony. Thus, the restoration of harmony through a ceremony can be part of a curing process.

5. It can be inferred from the discussion of illness and curing in paragraph 2 that

A. the Navajo consider illness to always have a supernatural cause

B. rituals involving songs and sand paintings may be used to treat an illness

C. when a Navajo is ill, ugly and disorderly sand paintings are made

D. after a serious illness, a Navajo will take part in a ceremony

Paragraph 3

Men make sand paintings that are accurate copies of paintings from the past. The songs sung over the paintings are also faithful renditions of songs from the past. By recreating these arts, which reflect the original beauty of creation, the Navajo bring beauty to the present world. As relative newcomers to the Southwest, a place where their climate, neighbors, and rulers could be equally inhospitable, the Navajo created these art forms to affect the world around them, not just through the recounting of the actions symbolized, but through the beauty and harmony of the artworks themselves. The paintings generally illustrate ideas and events from the life of a mythical hero, who, after being healed by the gods, gave gifts of songs and paintings. Working from memory, the artists re-create the traditional form of the image as accurately as possible.

6. The word “faithful” in the passage is closest in meaning to

A. modern

B. accurate

C. wonderful

D. simplified

7. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A. The Navajo used the symbolism and beauty of their works of art to improve their life in an often inhospitable environment.

B. The ideas the Navajo hold about symbolism and beauty were influenced by their inhospitable climate, neighbors, and rulers.

C. When they first arrived in the Southwest, the Navajo produced symbolic art forms that promoted harmony.

D. In their works of art, the Navajo emphasized beauty and harmony that can be found even under the most inhospitable circumstances.

8. According to paragraph 3, which of the following is often the subject of Navajo sand paintings?

A. The landscape of the Southwest

B. Traditional Navajo practices

C. Historical events that occurred in the Southwest

D. The lives of heroes in traditional Navajo stories

Paragraph 4

The Navajo are also world-famous for the designs on their woven blankets. Navajo women own the family flocks, control the shearing of the sheep, the carding, the spinning, and dying of the thread, and the weaving of the fabrics. While the men who make faithful copies of sand paintings from the past represent the principle of stability in Navajo thought, women embody dynamism and create new designs for every weaving they make. Weaving is a paradigm of the creativity of a mythic ancestor named Spider Woman who wove the universe as a cosmic web that united earth and sky. It was she who，according to legend, taught Navajo women how to weave. As they prepare their materials and weave. Navajo women imitate the transformations that originally created the world. Working on their looms, Navajo weavers create images through which they experience harmony with nature. It is their means of creating beauty and thereby contributing to the beauty, harmony, and healing of the world. Thus, weaving is a way of seeing the world and being part of it.

9. Paragraph 4 supports which of the following statements about Navajo weavers and weaving?

A. Navajo women oversee all aspects of wool production and weaving.

B. The wool used for blankets comes from different sheep than does the wool used for other purposes.

C. Navajo weavers have used some of the same designs for hundreds of years.

D. Weaving is done primarily for use in rituals.

10. The word “ancestor” in the passage is closest in meaning to

A. relative from an earlier generation

B. person who established a particular tradition in a society

C. hero from ancient times

D. person who once made important contributions to a social group or culture

11. Why does the author discuss “a mythic ancestor”?

A. To show how Navajo ideas of weaving have changed over time

B. To explain why the Navajo principle of stability is more clearly represented in their weavings than in their sand paintings

C. To emphasize the role of naturally occurring weaving materials in the creative weavings of the Navajo

D. To help explain the significance of weaving in Navajo culture

12. According to paragraph 4, Navajo weavers imitate

A. traditional weaving patterns

B. patterns used in sand paintings

C. the activities through which the world was created

D. images from nature

13. Look at the four squares [■]] that indicate where the following sentence could be added to the passage.

Since this purpose is limited to the context of the ritual, the paintings are destroyed when the ritual is completed.

Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

The Navajo, a Native American people living in the southwestern United States, live in small scattered settlements. In many respects, such as education, occupation, and leisure activities, their life is like that of other groups that contribute to the diverse social fabric of North American culture in the twenty-first century. At the same time, they have retained some traditional cultural practices that are associated with particular art forms. For example, the most important traditional Navajo rituals include the production of large floor paintings. These are actually made by pouring thin, finely controlled streams of colored sands or pulverized vegetable and mineral substances, pollen, and flowers in precise patterns on the ground. The largest of these paintings may be up to 5.5 meters in diameter and cover the entire floor of a room. Working from the inside of the design outward, the Navajo artist and his assistants will sift the black, white, bluish-gray, orange, and red materials through their fingers to create the finely detailed imagery. [■] The paintings and chants used in the ceremonies are directed by well-trained artists and singers who enlist the aid of spirits who are impersonated by masked performers. [■] The twenty-four known Navajo chants can be represented by up to 500 sand paintings. [■] These complex paintings serve as memory aids to guide the singers during the performance of the ritual songs, which can last up to nine days. [■]

14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selected THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.

To review the passage, click View Text.

Navajo art is fundamentally connected to aspects of Navajo ritual and belief.

Answer Choices

A. Navajo sand paintings are an expression of the close relationship between nature and the spiritual world in Navajo culture

B. Sand paintings, which help participants in rituals recall traditional chants, are part of ceremonies

designed to restore beauty and harmony.

C. Whereas Navajo sand paintings are associated with male deities. Navajo weaving involves representations of female figures such as Spider Woman.

D. Individual Navajo sand paintings typically embody the principles of harmony and disorder.

E. Sand paintings, which are created by Navajo men, are faithful re-creations of earlier works and as such represent the principle of stability.

F. In Navajo culture, weaving is a female art and is associated with creativity and change.

 

Climate of Venus

Earth has abundant water in its oceans but very little carbon dioxide in its relatively thin atmosphere. By contrast, Venus is very dry and its thick atmosphere is mostly carbon dioxide. The original atmospheres of both Venus and Earth were derived at least in part from gases spewed forth, or outgassed, by volcanoes. The gases that emanate from present-day volcanoes on Earth, such as Mount Saint Helens, are predominantly water vapor, carbon dioxide, and sulfur dioxide. These gases should therefore have been important parts of the original atmospheres of both Venus and Earth. Much of the water on both planets is also thought to have come from impacts from comets, icy bodies formed in the outer solar system.

In fact, water probably once dominated the Venusian atmosphere. Venus and Earth are similar in size and mass, so Venusian volcanoes may well have outgassed as much water vapor as on Earth, and both planets would have had about the same number of comets strike their surfaces. Studies of how stars evolve suggest that the early Sun was only about 70 percent as luminous as it is now, so the temperature in Venus’ early atmosphere must have been quite a bit lower. Thus water vapor would have been able to liquefy and form oceans on Venus. But if water vapor and carbon dioxide were once so common in the atmospheres of both Earth and Venus, what became of Earth’s carbon dioxide? And what happened to the water on Venus?

The answer to the first question is that carbon dioxide is still found in abundance on Earth, but now, instead of being in the form of atmospheric carbon dioxide, it is either dissolved in the oceans or chemically bound into carbonate rocks, such as the limestone and marble that formed in the oceans. If Earth became as hot as Venus, much of its carbon dioxide would be boiled out of the oceans and baked out of the crust. Our planet would soon develop a thick, oppressive carbon dioxide atmosphere much like that of Venus.

To answer the question about Venus’ lack of water, we must return to the early history of the planet. Just as on present-day Earth, the oceans of Venus limited the amount of atmospheric carbon dioxide by dissolving it in the oceans and binding it up in carbonate rocks. But being closer to the Sun than Earth is, enough of the liquid water on Venus would have vaporized to create a thick cover of water vapor clouds. Since water vapor is a greenhouse gas, this humid atmosphere—perhaps denser than Earth’s present-day atmosphere, but far less dense than the atmosphere that envelops Venus today—would have efficiently trapped heat from the Sun. At first, this would have had little effect on the oceans of Venus. Although the temperature would have climbed above 100° C, the boiling point of water at sea level on Earth, the added atmospheric pressure from water vapor would have kept the water in Venus’ oceans in the liquid state.

This hot and humid state of affairs may have persisted for several hundred million years. But as the Sun’s energy output slowly increased over time, the temperature at the surface would eventually have risen above 374°C. Above this temperature, no matter what the atmospheric pressure. Venus’ oceans would have begun to evaporate, and the added water vapor in the atmosphere would have increased the greenhouse effect. This would have made the temperature even higher and caused the oceans to evaporate faster, producing more water vapor. That, in turn, would have further intensified the greenhouse effect and made the temperature climb higher still.

Once Venus’ oceans disappeared, so did the mechanism for removing carbon dioxide from the atmosphere. With no oceans to dissolve it, outgassed carbon dioxide began to accumulate in the atmosphere, intensifying the greenhouse effect even more Temperatures eventually became high

enough to" bake out” any carbon dioxide that was trapped in carbonate rocks. This liberated carbon dioxide formed the thick atmosphere of present-day Venus. Over time, the rising temperatures would have leveled off, solar ultraviolet radiation having broken down atmospheric water vapor molecules into hydrogen and oxygen. With all the water vapor gone, the greenhouse effect would no longer have accelerated.

Paragraph 1

Earth has abundant water in its oceans but very little carbon dioxide in its relatively thin atmosphere. By contrast, Venus is very dry and its thick atmosphere is mostly carbon dioxide. The original atmospheres of both Venus and Earth were derived at least in part from gases spewed forth, or outgassed, by volcanoes. The gases that emanate from present-day volcanoes on Earth, such as Mount Saint Helens, are predominantly water vapor, carbon dioxide, and sulfur dioxide. These gases should therefore have been important parts of the original atmospheres of both Venus and Earth. Much of the water on both planets is also thought to have come from impacts from comets, icy bodies formed in the outer solar system.

1. According to paragraph 1, in what major respect are Venus and Earth different from each other?

A. Whether carbon dioxide v/as present in their original atmospheres

B. How thin their original atmospheres were

C. What their present-day atmospheres mainly consist of

D. How long ago they first developed an atmosphere

2. Why does the author mention "present-day volcanoes on Earth"?

A. To provide an example of an important difference between present-day Venus and present-day Earth

B. To help explain why Earth's atmosphere still contains traces of sulfur dioxide but Venus' does not

C. To indicate one source of information about the likely composition of the original atmospheres of Venus and Earth

D. To account for the fact that Earth’s water supply no longer comes primarily from impacting comets

Paragraph 2

In fact, water probably once dominated the Venusian atmosphere. Venus and Earth are similar in size and mass, so Venusian volcanoes may well have outgassed as much water vapor as on Earth, and both planets would have had about the same number of comets strike their surfaces. Studies of how stars evolve suggest that the early Sun was only about 70 percent as luminous as it is now, so the temperature in Venus’ early atmosphere must have been quite a bit lower. Thus water vapor would have been able to liquefy and form oceans on Venus. But if water vapor and carbon dioxide were once so common in the atmospheres of both Earth and Venus, what became of Earth’s carbon dioxide? And what happened to the water on Venus?

3. According to paragraph 2, what is one reason for thinking that at one time, there were significant amounts of water on Venus?

A. Because of Venus’ size and mass, its volcanoes probably produced much more water vapor than

volcanoes on Earth did.

B. The low temperature of Venus' early atmosphere can be explained only by the presence of water.

C. The presence of carbon dioxide in a planet's atmosphere is an indicator of water on that planet.

D. Venus probably was struck by roughly as many comets as Earth was.

4. The word “luminous” in the passage is closest in meaning to

A. dense

B. bright

C. large

D. active

Paragraph 3

The answer to the first question is that carbon dioxide is still found in abundance on Earth, but now, instead of being in the form of atmospheric carbon dioxide, it is either dissolved in the oceans or chemically bound into carbonate rocks, such as the limestone and marble that formed in the oceans. If Earth became as hot as Venus, much of its carbon dioxide would be boiled out of the oceans and baked out of the crust. Our planet would soon develop a thick, oppressive carbon dioxide atmosphere much like that of Venus.

5. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A. The first question to be answered is how Earth’s atmospheric carbon dioxide either got dissolved in the oceans or got chemically bound into carbonate rocks.

B. The fact that Earth’s abundant carbon dioxide is more often found in carbonate rock than dissolved in the oceans is the answer to the first question.

C. Earth still has abundant carbon dioxide, but instead of being in the atmosphere it is now dissolved in the oceans or chemically bound into ocean rocks.

D. The formation of limestone and marble used up the carbon dioxide that was dissolved in Earth’s oceans so that only carbon dioxide in atmospheric form remained.

Paragraph 4

To answer the question about Venus’ lack of water, we must return to the early history of the planet. Just as on present-day Earth, the oceans of Venus limited the amount of atmospheric carbon dioxide by dissolving it in the oceans and binding it up in carbonate rocks. But being closer to the Sun than Earth is, enough of the liquid water on Venus would have vaporized to create a thick cover of water vapor clouds. Since water vapor is a greenhouse gas, this humid atmosphere—perhaps denser than Earth’s present-day atmosphere, but far less dense than the atmosphere that envelops Venus today—would have efficiently trapped heat from the Sun. At first, this would have had little effect on the oceans of Venus. Although the temperature would have climbed above 100° C, the boiling point of water at sea level on Earth, the added atmospheric pressure from water vapor would have kept the water in Venus’ oceans in the liquid state.

6. According to paragraph 4, what is one factor that kept the amount of carbon dioxide in the

atmosphere of early Venus relatively low?

A. The presence of water vapor clouds

B. The presence of oceans

C. Rapidly increasing temperatures at ground level

D. Low atmospheric pressures

Paragraph 6

Once Venus’ oceans disappeared, so did the mechanism for removing carbon dioxide from the atmosphere. With no oceans to dissolve it, outgassed carbon dioxide began to accumulate in the atmosphere, intensifying the greenhouse effect even more Temperatures eventually became high enough to" bake out” any carbon dioxide that was trapped in carbonate rocks. This liberated carbon dioxide formed the thick atmosphere of present-day Venus. Over time, the rising temperatures would have leveled off, solar ultraviolet radiation having broken down atmospheric water vapor molecules into hydrogen and oxygen. With all the water vapor gone, the greenhouse effect would no longer have accelerated.

7. The phrase “mechanism for” in the passage is closest in meaning to

A. means of

B. importance of

C. need for

D. benefits of

Paragraph 5

This hot and humid state of affairs may have persisted for several hundred million years. But as the Sun’s energy output slowly increased over time, the temperature at the surface would eventually have risen above 374°C. Above this temperature, no matter what the atmospheric pressure. Venus’ oceans would have begun to evaporate, and the added water vapor in the atmosphere would have increased the greenhouse effect. This would have made the temperature even higher and caused the oceans to evaporate faster, producing more water vapor. That, in turn, would have further intensified the greenhouse effect and made the temperature climb higher still.

8. The word “persisted” in the passage is closest in meaning to

A. improved

B. continued

C. weakened

D. evolved

9. According to paragraph 5, what happens when temperatures rise above 374°C?

A. Atmospheric pressure begins to decrease.

B. Water vapor disappears from the atmosphere.

C. Water evaporates regardless of atmospheric pressure.

D. More energy is required to evaporate a given volume of water.

Paragraph 6

Once Venus’ oceans disappeared, so did the mechanism for removing carbon dioxide from the atmosphere. With no oceans to dissolve it, outgassed carbon dioxide began to accumulate in the atmosphere, intensifying the greenhouse effect even more Temperatures eventually became high enough to" bake out” any carbon dioxide that was trapped in carbonate rocks. This liberated carbon dioxide formed the thick atmosphere of present-day Venus. Over time, the rising temperatures would have leveled off, solar ultraviolet radiation having broken down atmospheric water vapor molecules into hydrogen and oxygen. With all the water vapor gone, the greenhouse effect would no longer have accelerated.

10. According to paragraph 6, extremely high temperatures increased the amount of carbon dioxide in Venus’ atmosphere by

A. increasing the rate which carbon dioxide was outgassed

B. baking out carbon dioxide from carbonate rocks

C. creating additional water vapor

D. replacing the previous mechanisms for removing carbon dioxide with less effective ones

11. The passage supports the idea that the basic reason that Venus and Earth are now so different from each other is that

A. early Venus had more frequent volcanic outgassing than early Earth did

B. early Venus had far less liquid water than early Earth did

C. volcanic activity stopped relatively early on Venus but continued on Earth

D. Venus is closer to the Sun than Earth is

Paragraph 5

12. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

This cycle of rising temperatures following an increase in greenhouse gases is known as the

runaway greenhouse effect.

Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

This hot and humid state of affairs may have persisted for several hundred million years. But as the Sun’s energy output slowly increased over time, the temperature at the surface would eventually have risen above 374°C. [■] Above this temperature, no matter what the atmospheric pressure. Venus’ oceans would have begun to evaporate, and the added water vapor in the atmosphere would have increased the greenhouse effect. [■] This would have made the temperature even higher and caused the oceans to evaporate faster, producing more water vapor. [■] That, in turn, would have further intensified the greenhouse effect and made the temperature climb higher still. [■]

13. Directions: Select from the seven phrases below the 2 phrases that correctly characterize early

Venus and the 3 phrases that correctly characterize present-day Venus. Drag each phrase you select into the appropriate column of the table. Two of the phrases will NOT be used. This question is worth 3 points.

Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.

To review the passage, click VIEW TEXT.

Early Venus

Present-day Venus

Answer Choices

A. High percentage of water vapor in the atmosphere

B. Carbon dioxide present only in atmospheric form

C. An atmosphere quite similar to that of early Earth

D. Very dense but relatively cool atmosphere

E. Completely covered with water

F. Complete absence of surface water

G. Essentially stable temperatures

Amphibian Thermoregulation

In contrast to mammals and birds, amphibians are unable to produce thermal energy through their metabolic activity, which would allow them to regulate their body temperature independent of the surrounding or ambient temperature. However, the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature. While amphibians are poor thermoregulators, they do exercise control over their body temperature to a limited degree.

Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail. The tolerance range in body temperature represents the range of temperatures within which a species can survive. One species of North American newt is still active when temperatures drop to -2°C while one South American frog feels comfortable even when temperatures rise to 41°C—the highest body temperature measured in a free-ranging amphibian. Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of -6°C with approximately one-third of their body fluids frozen. The other tissues are protected because they contain the frost-protective agents glycerin or glucose Additionally, in many species the tolerance boundaries are flexible and can change as a result of acclimatization (long-term exposure to particular conditions).

Frog species that remain exposed to the sun despite high diurnal (daytime) temperatures exhibit some fascinating modifications in the skin structure that function as morphological adaptations. Most amphibian skin is fully water permeable and is therefore not a barrier against evaporation or solar radiation. The African savanna frog Hyperolius viridiflavus stores guanine crystals in its skin, which enable it to better reflect solar radiation, thus providing protection against overheating. The tree frog Phyllomedusa sauvagei responds to evaporative losses with gland secretions that provide a greasy film over its entire body that helps prevent desiccation (dehydration).

However, behavior is by far the most important factor in thermoregulation. The principal elements in behavioral thermoregulation are basking (heliothermy), heat exchange with substrates such as rock or earth (thigmothermy), and diurnal and annual avoidance behaviors, which include moving to shelter during the day for cooling and hibernating or estivating (reducing activity during cold or hot weather, respectively) Heliothermy is especially common among frogs and toads: it allows them to increase their body temperature by more than 10°C. The Andean toad Bufo spinulosus exposes itself immediately after sunrise on moist ground and attains its preferred body temperature by this means, long before either ground or air is correspondingly warmed. A positive side effect of this approach is that it accelerates the digestion of the prey consumed overnight, thus also accelerating growth. Thigmothermy is a behavior present in most amphibians, although pressing against the ground serves a dual purpose: heat absorption by conductivity and water absorption through the skin. The effect of thigmothermy is especially evident in the Andean toad during rainfall: its body temperature corresponds to the temperature of the warm earth and not to the much cooler air temperature.

Avoidance behavior occurs whenever physiological and morphological adaptations are insufficient to maintain body temperature within the vital range. Nocturnal activity in amphibians with low tolerance for high ambient temperatures is a typical thermoregulatory behavior of avoidance. Seasonal avoidance behavior is extremely important in many amphibians. Species

whose habitat lies in the temperate latitudes are confronted by lethal low temperatures in winter, while species dwelling in semi- and regions are exposed to long dry, hot periods in summer.

In amphibians hibernation occurs in mud or deep holes away from frost. North of the Pyrenees Mountains, the natterjack toad offers a good example of hibernation, passing the winter dug deep into sandy ground. Conversely, natterjacks in southern Spain remain active during the mild winters common to the region and are instead forced into inactivity during the dry, hot summer season. Summer estivation also occurs by burrowing into the ground or hiding in cool, deep rock crevasses to avoid desiccation and lethal ambient temperature. Amphibians are therefore hardly at mercy of ambient temperature, since by means of the mechanisms described above they are more than )exercise some control over their body temperature.

paragraph 1

In contrast to mammals and birds, amphibians are unable to produce thermal energy through their metabolic activity, which would allow them to regulate their body temperature independent of the surrounding or ambient temperature. However, the idea that amphibians have no control whatsoever over their body temperature has been proven false because their body temperature does not always correspond to the surrounding temperature While amphibians are poor thermoregulators, they do exercise control over their body temperature to a limited degree.

1.According to paragraph 1, what indicates that amphibians have some control over their body temperature?

A. Amphibians can regulate their metabolic rates to generate energy.

B. Amphibians use the same means of thermoregulation as mammals and birds do.

C. The body temperature of amphibians sometimes differs from the temperature of their surroundings.

D. The body temperature of amphibians is independent of their metabolic activity.

paragraph 2

Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail. The tolerance range in body temperature represents the range of temperatures within which a species can survive. One species of North American newt is still active when temperatures drop to -2°C while one South American frog feels comfortable even when temperatures rise to 41°C—the highest body temperature measured in a free-ranging amphibian Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of -6°C with approximately one-third of their body fluids frozen. The other tissues are protected because they contain the frost-protective agents glycerin or glucose Additionally, in many species the tolerance boundaries are flexible and can change as a result of acclimatization (long-term exposure to particular conditions)

2.Why does the author mention a “South American frog” species in the passage?

A. To make the point that an amphibian’s temperature tolerance depends on a number of factors

B. To indicate how precise the range of body temperatures is for certain amphibians

C. To contrast its ability to adapt to that of the North American newt

D. To help illustrate the range of environmental conditions to which amphibians have adapted

3. According to paragraph 2, what allows some North American frog and toad species to survive in ambient temperatures well below freezing?

A. Their internal body temperatures never fall below -6°C.

B. They do not remain at temperatures below freezing for very long periods of time.

C. Their tolerance boundaries are flexible

D. Some of their body tissues contain substances that prevent freezing.

paragraph 3

Frog species that remain exposed to the sun despite high diurnal (daytime) temperatures exhibit some fascinating modifications in the skin structure that function as morphological adaptations. Most amphibian skin is fully water permeable and is therefore not a barrier against evaporation or solar radiation. The African savanna frog Hyperolius viridiflavus stores guanine crystals in its skin, which enable it to better reflect solar radiation, thus providing protection against overheating The tree frog Phyllomedusa sauvagei responds to evaporative losses with gland secretions that provide a greasy film over its entire body that helps prevent desiccation (dehydration).

4. “Phyllomedusa sauvager ” is mentioned as an example of a frog with an adaptation that

A. protects its glandular system

B. helps reduce its secretions

C. increases the amount of solar radiation that its skin can reflect

D. modifies its skin structure to protect against the drying effects of the sun

paragraph 4

However, behavior is by far the most important factor in thermoregulation. The principal elements in behavioral thermoregulation are basking (heliothermy), heat exchange with substrates such as rock or earth (thigmothermy), and diurnal and annual avoidance behaviors, which include moving to shelter during the day for cooling and hibernating or estivating (reducing activity during cold or hot weather, respectively) Heliothermy is especially common among frogs and toads: it allows them to increase their body temperature by more than 10°C. The Andean toad Bufo spinulosus exposes itself immediately after sunrise on moist ground and attains its preferred body temperature by this means, long before either ground or air is correspondingly warmed. A positive side effect of this approach is that it accelerates the digestion of the prey consumed overnight, thus also accelerating growth Thigmothermy is a behavior present in most amphibians, although pressing against the ground serves a dual purpose heat absorption by conductivity and water absorption through the skin The effect of thigmothermy is especially evident in the Andean toad during rainfall its body temperature corresponds to the temperature of the warm earth and not to the much cooler air temperature.

5. Paragraph 4 mentions each of the following as an example of behavioral thermoregulation EXCEPT

A. pressing against the ground

B. speeding up of the metabolism

C. reducing activity during the summer

D. adjusting exposure to the sun

6. The “Andean toad Bufo spinulosus” illustrates which of the following behavioral modifications?

A. Heliothermy and thigmothermy

B. Diurnal avoidance behavior

C. Absorbing heat from the air

D. Moving to shelter during the summer

7. The word “attains” in the passage is closest in meaning to

A. raises

B. lowers

C. reaches

D. regulates

8. The phrase “this approach” in the passage refers to

A gradually increasing body temperature by 10°C

B. basking as soon as the sun comes up

C. waiting for the ground and air to warm

D. keeping body temperature above the temperature of the air

paragraph 5

Avoidance behavior occurs whenever physiological and morphological adaptations are insufficient to maintain body temperature within the vital range Nocturnal activity in amphibians with low tolerance for high ambient temperatures is a typical thermoregulatory behavior of avoidance. Seasonal avoidance behavior is extremely important in many amphibians. Species whose habitat lies in the temperate latitudes are confronted by lethal low temperatures in winter, while species dwelling in semi- and regions are exposed to long dry, hot periods in summer.

9. According to paragraph 5, why is avoidance behavior important for some amphibians?

A. Amphibians’ habitats are areas where temperatures vary from day to day.

B. Amphibians have less tolerance for high ambient temperatures than for low ambient temperatures.

C. Amphibians lack adequate physiological adaptations for dealing with ambient temperatures.

D. Amphibians cannot protect themselves from the extreme summer heat by being active only at night.

10. The word “dwelling” in the passage is closest in meaning to

A. arriving

B. originating

C. evolving

D. living

paragraph 6

In amphibians hibernation occurs in mud or deep holes away from frost North of the Pyrenees Mountains, the natterjack toad offers a good example of hibernation, passing the winter dug deep into sandy ground. Conversely, natterjacks in southern Spain remain active during the mild winters common to the region and are instead forced into inactivity during the dry, hot summer season. Summer estivation also occurs by burrowing into the ground or hiding in cool, deep rock crevasses to avoid desiccation and lethal ambient temperature. Amphibians are therefore hardly at mercy of ambient temperature, since by means of the mechanisms described above they are more than exercise some control over their body temperature.

11. In paragraph 6, which of the following can be inferred from the discussion of the natterjack?

A. Amphibians have greater tolerance for heat than for cold.

B. Desiccation is not a threat to amphibians

C. Both hibernation and estivation may serve as avoidance behaviors depending on the climate

D. Some species of amphibians are active only in the spring and in the fall

12. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A. Thus, although amphibians use the various mechanisms described above, they have hardly any control of their body temperature

B. Thus, by the mechanisms described above, amphibians are quite capable of controlling their body temperature to survive extreme ambient temperatures.

C. Thus, unless they can use the mechanisms described above, amphibians are at the mercy of ambient temperatures.

D. Thus, the mechanisms described above give amphibians control over much more than just their body temperature

13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

On the other hand, amphibians in very hot climates use secretions from the mucus glands to decrease their temperature through evaporative cooling on the skin.

Where would the sentence best fit? Click on square [■] to add the sentence to the passage.

Physiological adaptations can assist amphibians in colonizing habitats where extreme conditions prevail. The tolerance range in body temperature represents the range of temperatures within which a species can survive. One species of North American newt is still active when temperatures drop to -2°C while one South American frog feels comfortable even when temperatures measured to 41°C—the highest body temperature measured in a free-ranging amphibian. [■] Recently it has been shown that some North American frog and toad species can survive up to five days with a body temperature of -6°C with approximately one-third of their body fluids frozen. [■] The other tissues are protected because they contain the frost-protective agents glycerin or glucose. [■] Additionally, in many species the tolerance boundaries are flexible

and can change as a result of acclimatization (long-term exposure to particular conditions).[■]

14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selected THREE answer choices that express the most important ideas in the passage.Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage.This question is worth 2 points.

Drag your choices to the spaces where they belong. To review the passage, click on View Text.

A number of factors may help account for the difference in biodiversity between low and high latitudes.

Answer Choices

A. Frogs, which survive temperature ranges from as low as -2°C to as high as 41°C, are evidence that amphibians are independent of ambient temperatures

B. Amphibians can increase their body temperature by exposing themselves to the sun (heliothermy) and by pressing against the ground (thigmothermy).

C. Avoidance behaviors, such as sheltering from the sun, as well as estivation and hibernation，help amphibians control their body temperature.

D. Physical adaptations offer amphibians a number of ways to protect against extreme or dangerous climate conditions.

E. Sunrise is the time when some amphibian species have the greatest need for thermoregulatory mechanisms.

F. Hibernation always involves digging deep holes in mud or sand, whereas estivation sometimes involves nothing more than hiding in deep rock crevasses

 

Trade and Early State Formation

Bartering was a basic trade mechanism for many thousands of years; often sporadic and usually based on notions of reciprocity, it involved the mutual exchange of commodities or objects between individuals or groups. Redistribution of these goods through society lay in the hands of chiefs, religious leaders, or kin groups. Such redistribution was a basic element in chiefdoms. The change from redistribution to formal trade—often based on regulated commerce that perhaps involved fixed prices and even currency—was closely tied to growing political and social complexity and hence to the development of the state in the ancient world.

In the 1970s, a number of archaeologists gave trade a primary role in the rise of ancient states. British archaeologist Colin Renfrew attributed the dramatic flowering of the Minoan civilization on Crete and through the Aegean to intensified trading contacts and to the impact of olive and vine cultivation on local communities. As agricultural economies became more diversified and local food supplies could be purchased both locally and over longer distances, a far-reaching economic interdependence resulted. Eventually, this led to redistribution systems for luxuries and basic commodities, systems that were organized and controlled by Minoan rulers from their palaces. As time went on, the self-sufficiency of communities was replaced by mutual dependence. Interest in long-distance trade brought about some cultural homogeneity from trade and gift exchange, and perhaps even led to piracy. Thus, intensified trade and interaction, and the flowering of specialist crafts, in a complex process of positive feedback, led to much more complex societies based on palaces, which were the economic hubs of a new Minoan civilization.

Renfrew’s model made some assumptions that are now discounted. For example, he argued that the introduction of domesticated vines and olives allowed a substantial expansion of land under cultivation and helped to power the emergence of complex society. Many archaeologists and paleobotanists now question this view, pointing out that the available evidence for cultivated vines and olives suggests that they were present only in the later Bronze Age. Trade, nevertheless, was probably one of many variables that led to the emergence of palace economies in Minoan Crete.

American archaeologist William Rathje developed a hypothesis that considered an explosion in long-distance exchange a fundamental cause of Mayan civilization in Mesoamerica. He suggested that the lowland Mayan environment was deficient in many vital resources, among them obsidian, salt, stone for grinding maize, and many luxury materials. All these could be obtained from the nearby highlands, from the Valley of Mexico, and from other regions, if the necessary trading networks came into being. Such connections, and the trading expeditions to maintain them, could not be organized by individual villages. The Maya lived in a relatively uniform environment, where every community suffered from the same resource deficiencies. Thus, argued Rathje, long--distance trade networks were organized through local ceremonial centers and their leaders. In time, this organization became a state, and knowledge of its functioning was exportable, as were pottery, tropical bird feathers, specialized stone materials, and other local commodities.

Rathje’s hypothesis probably explains part of the complex process of Mayan state formation, but it suffers from the objection that suitable alternative raw materials can be found in the lowlands. It could be, too, that warfare became a competitive response to population growth and to the increasing scarcity of prime agricultural land, and that it played an important role in the emergence of the Mayan states.

Now that we know much more about ancient exchange and commerce, we know that, because

no one aspect of trade was an overriding cause of cultural change or evolution in commercial practices, trade can never be looked on as a unifying factor or as a primary agent of ancient civilization. Many ever-changing variables affected ancient trade, among them the demand for goods. There were also the logistics of transportation, the extent of the trading network, and the social and political environment. Intricate market networks channeled supplies along well-defined routes. Authorities at both ends might regulate the profits fed back to the source, providing the incentive for further transactions. There may or may not have been a market organization. Extensive long-distance trade was a consequence rather than a cause of complex societies.

Paragraph 1

Bartering was a basic trade mechanism for many thousands of years; often sporadic and usually based on notions of reciprocity, it involved the mutual exchange of commodities or objects between individuals or groups. Redistribution of these goods through society lay in the hands of chiefs, religious leaders, or kin groups. Such redistribution was a basic element in chiefdoms. The change from redistribution to formal trade—often based on regulated commerce that perhaps involved fixed prices and even currency—was closely tied to growing political and social complexity and hence to the development of the state in the ancient world.

1. The word "notions" in the passage is closest in meaning to

A. ideas

B. rules

C. degrees

D. traditions

2. According to paragraph 1, what development occurred as political and social complexity increased?

A. The prices of most commodities rose.

B. Formal trade emerged.

C. Chiefs became more powerful

D. Bartering became the preferred means of trade.

Paragraph 2

In the 1970s, a number of archaeologists gave trade a primary role in the rise of ancient states. British archaeologist Colin Renfrew attributed the dramatic flowering of the Minoan civilization on Crete and through the Aegean to intensified trading contacts and to the impact of olive and vine

cultivation on local communities. As agricultural economies became more diversified and local food supplies could be purchased both locally and over longer distances, a far-reaching economic interdependence resulted. Eventually, this led to redistribution systems for luxuries and basic commodities, systems that were organized and controlled by Minoan rulers from their palaces. As time went on, the self-sufficiency of communities was replaced by mutual dependence. Interest in long-distance trade brought about some cultural homogeneity from trade and gift exchange, and perhaps even led to piracy. Thus, intensified trade and interaction, and the flowering of specialist crafts, in a complex process of positive feedback, led to much more complex societies based on palaces, which were the economic hubs of a new Minoan civilization.

3. The word “diversified” in the passage is closest in meaning to

A. organized

B. selective

C. varied

D. efficient

4. According to paragraph 2, which of the following controlled the systems of redistribution of goods in ancient Crete?

A. Local community leaders

B. Olive growers

C. Minoan rulers

D. Long-distance traders

5. According to paragraph 2, Renfrew believed that one effect of long-distance trade in the Aegean was

A. a greater effort to control piracy

B. greater cultural similarity throughout the region

C. a decline in local olive production

D. a decline in the use of luxuries for gift exchanges

Paragraph 3

Renfrew’s model made some assumptions that are now discounted. For example, he argued that the introduction of domesticated vines and olives allowed a substantial expansion of land under cultivation and helped to power the emergence of complex society. Many archaeologists and paleobotanists now question this view, pointing out that the available evidence for cultivated vines and olives suggests that they were present only in the later Bronze Age. Trade, nevertheless, was probably one of many variables that led to the emergence of palace economies in Minoan Crete.

6. According to paragraph 3, what was a major problem with Renfrew’s model?

A. He overlooked the fact that only the Minoan palaces had access to domesticated vines and olives.

B. He wrongly assumed that the introduction of domesticated vines and olives led to the cultivation of more land.

C. Trade in domesticated plants was much more important to the emergence of Minoan palace economies than he thought.

D. Domesticated vines and olives do not appear to have been available as early as he thought

Paragraph 4

American archaeologist William Rathje developed a hypothesis that considered an explosion in long-distance exchange a fundamental cause of Mayan civilization in Mesoamerica. He suggested that the lowland Mayan environment was deficient in many vital resources, among them obsidian, salt, stone for grinding maize, and many luxury materials. All these could be obtained from the nearby highlands, from the Valley of Mexico, and from other regions, if the necessary trading networks came into being. Such connections, and the trading expeditions to maintain them, could not be organized by individual villages. The Maya lived in a relatively uniform environment, where every community suffered from the same resource deficiencies. Thus, argued Rathje, long--distance trade networks were organized through local ceremonial centers and their leaders. In time, this organization became a state, and knowledge of its functioning was exportable, as were pottery, tropical bird feathers, specialized stone materials, and other local commodities.

7. According to paragraph 4, which of the following was true about ancient Mayan communities?

A. They each created their own separate trading networks with communities in the nearby highlands.

B. They all had many luxury materials that they were able to trade for resources that they lacked.

C. They all needed to obtain a number of important materials through trade with other regions.

D. They all gradually reduced their trading activities with communities in the Valley of Mexico and developed trading networks with other regions.

8. What can be inferred from the fact that the Maya lived in a “relatively uniform environment”?

A. The communities could not obtain resources they lacked by trading with each other.

B. The communities’ ceremonial centers were all organized in much the same way.

C. Increased competition between the communities to export their local commodities expanded commercial networks beyond the nearby highlands.

D. Different communities tended to specialize in the production of different commodities.

Paragraph 5

Rathje’s hypothesis probably explains part of the complex process of Mayan state formation, but it suffers from the objection that suitable alternative raw materials can be found in the lowlands. It could be, too, that warfare became a competitive response to population growth and to the increasing scarcity of prime agricultural land, and that it played an important role in the emergence of the Mayan states.

Paragraph 4

American archaeologist William Rathje developed a hypothesis that considered an explosion in long-distance exchange a fundamental cause of Mayan civilization in Mesoamerica. He suggested that the lowland Mayan environment was deficient in many vital resources, among them obsidian, salt, stone for grinding maize, and many luxury materials. All these could be obtained from the nearby highlands, from the Valley of Mexico, and from other regions, if the necessary trading networks came into being. Such connections, and the trading expeditions to maintain them, could not be organized by individual villages. The Maya lived in a relatively uniform environment, where every community suffered from the same resource deficiencies. Thus, argued Rathje, long-

-distance trade networks were organized through local ceremonial centers and their leaders. In time, this organization became a state, and knowledge of its functioning was exportable, as were pottery, tropical bird feathers, specialized stone materials, and other local commodities.

9. The word “prime” in the passage is closest in meaning to

A. low-lying

B. easily accessible

C. unused

D. high-quality

10. What is the role of paragraph 5 in relation to paragraph 4?

A. It restates the hypothesis presented in paragraph 4 and reinforces it with further evidence.

B. It presents evidence that the hypothesis discussed in paragraph 4 confuses cause and effect.

C. It presents a critical assessment of the hypothesis presented in paragraph 4.

D. It explains how the hypothesis discussed in paragraph 4 was initially formulated.

Paragraph 6

Now that we know much more about ancient exchange and commerce, we know that, because no one aspect of trade was an overriding cause of cultural change or evolution in commercial practices, trade can never be looked on as a unifying factor or as a primary agent of ancient civilization. Many ever-changing variables affected ancient trade, among them the demand for goods. There were also the logistics of transportation, the extent of the trading network, and the social and political environment. Intricate market networks channeled supplies along well-defined routes. Authorities at both ends might regulate the profits fed back to the source, providing the incentive for further transactions. There may or may not have been a market organization. Extensive long-distance trade was a consequence rather than a cause of complex societies.

11. Which of the sentences below best expresses the essential information in the highlighted sentence in the passage? Incorrect choices change the meaning in important ways or leave out essential information.

A. We now know that ancient trade cannot be considered a main factor in the rise of civilization, because no one aspect of it caused change in culture or commercial practices.

B. We now know that the growth of civilization was an important factor in causing cultural change and in improving commercial practices.

C. We now know much more about how ancient trade and commerce led to cultural changes and the evolution of commercial practices.

D. We now know much more about the main factors and agents that led to ancient civilization, because we know what aspects of trade affected culture and commercial practices.

12. According to paragraph 6, all of the following statements about trade in ancient civilizations are true EXCEPT:

A. The spread of trade was influenced by many variables, none of which was the main cause.

B. Political conditions were more important than demand for goods in the development of trade.

C. Some markets had clearly established trading routes.

D. The regulation of profits provided incentives for future trade.

13. Look at the four squares [■] that indicate where the following sentence could be added to the passage.

But demand for locally unobtainable resources was clearly only a part of the story.

Where would the sentence best fit? Click on a square [■] to add the sentence to the passage.

Now that we know much more about ancient exchange and commerce, we know that, because no one aspect of trade was an overriding cause of cultural change or evolution in commercial practices, trade can never be looked on as a unifying factor or as a primary agent of ancient civilization. [■] Many ever-changing variables affected ancient trade, among them the demand for goods. [■] There were also the logistics of transportation, the extent of the trading network, and the social and political environment. [■] Intricate market networks channeled supplies along well-defined routes. [■] Authorities at both ends might regulate the profits fed back to the source, providing the incentive for further transactions. There may or may not have been a market organization. Extensive long-distance trade was a consequence rather than a cause of complex societies.

14. Directions: An introductory sentence for a brief summary of the passage is provided below. Complete the summary by selecting the THREE answer choices that express the most important ideas in the passage. Some sentences do not belong in the summary because they express ideas that are not presented in the passage or are minor ideas in the passage. This question is worth 2 points.

Drag your answer choices to the spaces where they belong. To remove an answer choice, click on it.

To review the passage, click VIEW TEXT.

Various attempts have been made to explore the role that trade played in the rise of ancient states.

Answer Choices

A. Barter, a basic trade mechanism that involved the direct exchange of goods or services, depended on a high degree of social complexity.

B. It was only in the 1970s that most archaeologists began to realize that the long-distance trade typical of Minoan communities varied significantly from that of lowland Mayan communities.

C. Renfrew and Rathje are recognized today for having correctly analyzed the basic relationship between trade and the emergence of states, even though they were wrong about many details.

D. Renfrew suggested that an organized state emerged in Minoan Crete because of intensified trade,

but current views indicate that trade was probably only one of many variables.

E. Rathje's hypothesis that long-distance trade led to the emergence of a Mayan state has been objected to, and it is argued that other factors such as warfare may have played an important role too.

F. Current views indicate that trade was not the most important agent of ancient civilization and that long-distance trade was a result rather than a cause of complex societies.

 

托福TPO阅读41答案

阅读一:1-5.BDCDB 6-10.BADAA 11-13.DCD 14.BEF

阅读二:1-5.CCDBC 6-10.BABCB 11-13.BDD 14.AC-BEG

阅读三:1-5.ABCCB 6-10.DCADC 11-13.ABB 14.DEF

 

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