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Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.The word ‘susceptible’ could be best replaced by _____.

Xem chi tiết 598 lượt xem 5 năm trước

Read the following passage and mark the letter A,B,C or D on your answer sheet to indicate the correct answer to each of the questions from 25 to 34Historically parents have played a major role in choosing marriage partners for their children, andthe custom continues in the world’s developing countries today. Parental influence is greatest when the parents have a large stake in whom their child marries. Traditionally, marriage has been regarded as an alliance between two families, rather than just between the two individuals. Aristocratic families could enhance their wealth or acquire royal titles through a child’s marriage. Marriage was also used as a way of sealing peace between former enemies, whether they were kings or feuding villagers.The most extreme form of parental influence is an arranged marriage in which the bride and groom have no say at all. For instance, in traditional Chinese practice, the bride and groom meet for the first time on their wedding day. In some upper-caste Hindu marriages, children are betrothed at a very young age and have no voice in the decision. In a less extreme form of arranged marriage, parents may do the matchmaking, but the young people can veto the choice. Some small cultures scattered around the world have what social scientists call preferential marriage. In this system, the bride or groom is supposed to marry a particular kind of person—for example, a cousin on the mother’s or father’s side of the family.In many traditional societies, marriage typically involved transfers of property from the parents to their marrying children or from one set of parents to the other. These customs persist in some places today and are part of the tradition of arranged marriages. For example, in some cultures the bride’s parents may give property (known as a dowry) to the new couple. The practice of giving dowries has been common in countries such as Greece, Egypt, India, and China from ancient times until the present. It was also typical in European societies in the past. Although the giving of dowries has been part of the norms of marriage in these cultures, often only those people with property could afford to give a dowry to the young couple.Families use dowries to attract a son-in-law with desirable qualities, such as a particularly bright manfrom a poor but respectable family or a man with higher status but with less money than the bride’s family has. In societies in which the giving of dowries is customary, families with many daughters can become impoverished by the costs of marriage. For this reason, in Europe in earlier times some families sent “extra” daughters to convents. In India and China, where it is expected that every woman will marry, families have sometimes tried to limit the number of daughters born to them.Which of the following could be the most suitable title for the whole passage?

Xem chi tiết 3.8 K lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.The author suggests that melanin _____.

Xem chi tiết 422 lượt xem 5 năm trước

Read the passage, then choose the best answer by circling the letter A, B, C or D ( 15p ): In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater.   Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs.   Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.    The adaptation process described in the article was completed……………….

Xem chi tiết 411 lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.It can be inferred from the passage that the principle of use and disuse enables organisms to _____.

Xem chi tiết 775 lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.From the passage, it can be inferred that the author views body building _____.

Xem chi tiết 348 lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.According to the passage, men who body build_____.

Xem chi tiết 424 lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.The word ‘Those’ in line 3 refers to _____.

Xem chi tiết 2.1 K lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C, or D on your answer sheet to indicate the correct answer to each of the questions from 36 to 42.The principle of use and disuse states that those parts of organisms’ bodies that are used grow larger. Those parts that are not tend to wither away. It is an observed fact that when you exercise particular muscles, they grow. Those that are never used diminish. By examining a man’s body, we can tell which muscles he uses and which he does not. We may even be able to guess his profession or his recreation. Enthusiasts of the ‘body-building’ cult make use of the principle of use and disuse to ‘build’ their bodies, almost like a piece of sculpture, into whatever unnatural shape is demanded by fashion in this peculiar minority culture. Muscles are not the only parts of the body that respond to use in this kind of way. Walk barefoot and you acquire harder skin on your soles. It is easy to tell a farmer from a bank teller by looking at their hands alone. The farmer’s hands are horny, hardened by long exposure to rough work. The teller’s hands are relatively soft.The principle of use and disuse enables animals to become better at the job of surviving in their world, progressively better during their lifetime as a result of living in that world. Humans, through direct exposure to sunlight, or lack of it, develop a skin color which equips them better to survive in the particular local conditions. Too much sunlight is dangerous. Enthusiastic sunbathers with very fair skins are susceptible to skin cancer. Too little sunlight, on the other hand, leads to vitamin-D deficiency. The brown pigment melanin which is synthesized under the influence of sunlight, makes a screen to protect the underlying tissues from the harmful effects of further sunlight. If a suntanned person moves to a less sunny climate, the melanin disappears, and the body is able to benefit from what little sun there is. This can be represented as an instance of the principle of use and disuse: skin goes brown when it is “used’, and fades to white when it is not.What does the passage mainly discuss?

Xem chi tiết 4.3 K lượt xem 5 năm trước

Read the passage, then choose the best answer by circling the letter A, B, C or D ( 15p ): In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater.   Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs.   Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.   The seashore was a barrier for descendants of fish-type because ………………… 

Xem chi tiết 1 K lượt xem 5 năm trước

Read the following passage and choose A, B, C, or D to indicate the correct word or phrase that best fits each of the following blanks. Fill in the appropriate word in question 35For Nigel Portman, a love of travelling began with what’s called a ‘gap year’. In common with many other British teenagers, he chose to take a year out before (31)____ to study for his degree. After doing various jobs to raise some money, he left home to gain some experience of life in different cultures, visiting America and Asia. The more adventurous the young person, the (32)_____ the challenge they are likely to set themselves for the gap year, and for some, like Nigel, it can result in a thirst for adventure. Now that his university course has (33)______ to an end, Nigel is just about to leave on a three-year trip that will take him all around the world. What’s more, he plans to make the whole journey using only means of transport which are powered by natural energy. In other words, he’ll be (34)______ mostly on bicycles and his own legs; and when there’s an ocean to cross, he won’t be taking a short cut by climbing aboard a plane, he’ll be joining the crew of a sailing ship instead. As well as doing some mountain climbing and other outdoor pursuits along the way, Nigel hopes to (35)______ on to the people he meets the environmental message that lies behind the whole idea. 

Xem chi tiết 2.8 K lượt xem 5 năm trước

Read the following passage and choose A, B, C, or D to indicate the correct word or phrase that best fits each of the following blanks. Fill in the appropriate word in question 34For Nigel Portman, a love of travelling began with what’s called a ‘gap year’. In common with many other British teenagers, he chose to take a year out before (31)____ to study for his degree. After doing various jobs to raise some money, he left home to gain some experience of life in different cultures, visiting America and Asia. The more adventurous the young person, the (32)_____ the challenge they are likely to set themselves for the gap year, and for some, like Nigel, it can result in a thirst for adventure. Now that his university course has (33)______ to an end, Nigel is just about to leave on a three-year trip that will take him all around the world. What’s more, he plans to make the whole journey using only means of transport which are powered by natural energy. In other words, he’ll be (34)______ mostly on bicycles and his own legs; and when there’s an ocean to cross, he won’t be taking a short cut by climbing aboard a plane, he’ll be joining the crew of a sailing ship instead. As well as doing some mountain climbing and other outdoor pursuits along the way, Nigel hopes to (35)______ on to the people he meets the environmental message that lies behind the whole idea.

Xem chi tiết 501 lượt xem 5 năm trước

Read the following passage and choose A, B, C, or D to indicate the correct word or phrase that best fits each of the following blanks. Fill in the appropriate word in question 33For Nigel Portman, a love of travelling began with what’s called a ‘gap year’. In common with many other British teenagers, he chose to take a year out before (31)____ to study for his degree. After doing various jobs to raise some money, he left home to gain some experience of life in different cultures, visiting America and Asia. The more adventurous the young person, the (32)_____ the challenge they are likely to set themselves for the gap year, and for some, like Nigel, it can result in a thirst for adventure. Now that his university course has (33)______ to an end, Nigel is just about to leave on a three-year trip that will take him all around the world. What’s more, he plans to make the whole journey using only means of transport which are powered by natural energy. In other words, he’ll be (34)______ mostly on bicycles and his own legs; and when there’s an ocean to cross, he won’t be taking a short cut by climbing aboard a plane, he’ll be joining the crew of a sailing ship instead. As well as doing some mountain climbing and other outdoor pursuits along the way, Nigel hopes to (35)______ on to the people he meets the environmental message that lies behind the whole idea.

Xem chi tiết 1.8 K lượt xem 5 năm trước

Read the passage, then choose the best answer by circling the letter A, B, C or D ( 15p ): In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater.   Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs.   Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.   Animals found desert living possible only……………………. 

Xem chi tiết 862 lượt xem 5 năm trước

Read the following passage and choose A, B, C, or D to indicate the correct word or phrase that best fits each of the following blanks. Fill in the appropriate word in question 32For Nigel Portman, a love of travelling began with what’s called a ‘gap year’. In common with many other British teenagers, he chose to take a year out before (31)____ to study for his degree. After doing various jobs to raise some money, he left home to gain some experience of life in different cultures, visiting America and Asia. The more adventurous the young person, the (32)_____ the challenge they are likely to set themselves for the gap year, and for some, like Nigel, it can result in a thirst for adventure. Now that his university course has (33)______ to an end, Nigel is just about to leave on a three-year trip that will take him all around the world. What’s more, he plans to make the whole journey using only means of transport which are powered by natural energy. In other words, he’ll be (34)______ mostly on bicycles and his own legs; and when there’s an ocean to cross, he won’t be taking a short cut by climbing aboard a plane, he’ll be joining the crew of a sailing ship instead. As well as doing some mountain climbing and other outdoor pursuits along the way, Nigel hopes to (35)______ on to the people he meets the environmental message that lies behind the whole idea.

Xem chi tiết 593 lượt xem 5 năm trước

Read the following passage and choose A, B, C, or D to indicate the correct word or phrase that best fits each of the following blanks. Fill in the appropriate word in question 31For Nigel Portman, a love of travelling began with what’s called a ‘gap year’. In common with many other British teenagers, he chose to take a year out before (31)____ to study for his degree. After doing various jobs to raise some money, he left home to gain some experience of life in different cultures, visiting America and Asia. The more adventurous the young person, the (32)_____ the challenge they are likely to set themselves for the gap year, and for some, like Nigel, it can result in a thirst for adventure. Now that his university course has (33)______ to an end, Nigel is just about to leave on a three-year trip that will take him all around the world. What’s more, he plans to make the whole journey using only means of transport which are powered by natural energy. In other words, he’ll be (34)______ mostly on bicycles and his own legs; and when there’s an ocean to cross, he won’t be taking a short cut by climbing aboard a plane, he’ll be joining the crew of a sailing ship instead. As well as doing some mountain climbing and other outdoor pursuits along the way, Nigel hopes to (35)______ on to the people he meets the environmental message that lies behind the whole idea.

Xem chi tiết 1.6 K lượt xem 5 năm trước

Read the passage, then choose the best answer by circling the letter A, B, C or D ( 15p ): In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater.   Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs.   Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.   An example of an amphibian's incomplete adaptation to land life is…………………….. 

Xem chi tiết 575 lượt xem 5 năm trước

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct answer to each of the questions .         All mammals feed their young. Beluga whale mothers, for example, nurse their calves for some twenty months, until they are about to give birth again and their young are able to find their own food. The behavior of feeding of the young is built into the reproductive system. It is a nonelective part of parental care and the defining feature of a mammal, the most important thing that mammals-- whether marsupials, platypuses, spiny anteaters, or placental mammals -- have in common.But not all animal parents, even those that tend their offspring to the point of hatching or birth, feed their young. Most egg-guarding fish do not, for the simple reason that their young are so much smaller than the parents and eat food that is also much smaller than the food eaten by adults. In reptiles, the crocodile mother protects her young after they have hatched and takes them down to the water, where they will find food, but she does not actually feed them. Few insects feed their young after hatching, but some make other arrangement, provisioning their cells and nests with caterpillars and spiders that they have paralyzed with their venom and stored in a state of suspended animation so that their larvae might have a supply of fresh food when they hatch.            For animals other than mammals, then, feeding is not intrinsic to parental care. Animals add it to their reproductive strategies to give them an edge in their lifelong quest for descendants. The most vulnerable moment in any animal's life is when it first finds itself completely on its own, when it must forage and fend for itself. Feeding postpones that moment until a young animal has grown to such a size that it is better able to cope. Young that are fed by their parents become nutritionally independent at a much greater fraction of their full adult size. And in the meantime those young are shielded against the vagaries of fluctuating of difficult-to-find supplies. Once a species does take the step of feeding its young, the young become totally dependent on the extra effort. If both parents are removed, the young generally do not surviveThe word "shielded" in line 22 is closest in meaning to

Xem chi tiết 449 lượt xem 5 năm trước

Read the passage, then choose the best answer by circling the letter A, B, C or D ( 15p ): In the very distant geological past, all animals were aquatic. The very first vertebrates or animals with backbones, of which we have any fossil record, lived in water. These vertebrates, the fish, were adapted to underwater living. Their streamlined bodies were covered with scales to reduce surface friction: they had muscular tails so that they could swim swiftly in such a dense medium as water; and they were endowed with gills for breathing underwater.   Descendants of fish-type ancestors crossed the seashore barrier and accommodated themselves to life on land. As amphibians, they possessed limbs instead of fins and lungs instead of gills. But they never became completely free of the bonds that tied them to the water; even today many amphibians return to the water to lay their eggs.   Millions of years after the first clumsy amphibians crawled over the land, newer types of land dwellers appeared, these animals give rise to the present-day reptiles and mammals. They were completely converted for land dwelling, with bodies and biological activities far different from those of fish. With these special adaptations, mammals have been able to colonize the woods and meadows, the deserts and high mountains, often far removed from the sea.   The passage suggests that the first amphibians used their limbs to………….. 

Xem chi tiết 1 K lượt xem 5 năm trước