Danh sách câu hỏi ( Có 86,238 câu hỏi trên 1,725 trang )

  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. ENGLISH SEVENTH MEETING “SAN ANDREAS FAULT” The San Andreas Fault line is a fracture at the congruence of two major plates of the Earth’s crust, one of which support most of the North American continent, and the other of which underlies the coast of California and part of the ocean floor of the Pacific Ocean. The fault originates about six hundred miles south of the Gulf of California, runs north in an irregular line along the western coast to San Francisco, and continues north for about two hundred more miles before angling off into the ocean. In places, the trace of the fault is marked by a trench, or, in geological terms, a rift, and a small ponds dot the landscape. Its western side always move north in relation to its eastern side. The total net slip along the San Andreas Fault and the length of time it has been active are matters of conjecture, but it has been estimated that, during the past fifteen million years, coastal California along the San Andreas Fault has moved about 190 miles in a northwesterly direction with respect to the North American plate. Although the movement along the fault averages only a few inches a year, it is intermittent and variable. Some segments of the fault do not have move at all for long periods of time, building up tremendous pressure that must be released. For this reason, tremors are not unusual along the San Andreas Fault, some of which are classified as major earthquakes. Also for this reason, small tremors are interpreted as safe, since they are understood to be pressure that releases without causing much damage. It is worth noting that the San Andreas Fault passes uncomfortably close to several major metropolitan areas, including Los Angeles and San Francisco. In addition, the San Andreas Fault has created smaller fault systems, many of which underlie the smaller towns and cities along the California coast. For this reason, Californians have long anticipated the recurrence of what they refer to as “the Big One”, a chain reaction of destructive earthquakes that would measure near 8 on the Richter scale, similar in intensity to those that occurred in 1857 and 1906. Such a quake would wreak devastating effects on the life and property in the region. Unfortunately, as pressure continues to build along the fault, the likelihood of such an earthquake increases substantially. What is the author’s main purpose in the passage?  

Xem chi tiết 733 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 word or phrase that best fits each of the numbered blanks. THE HISTORY OF WRITING The development of writing (30) _______ a huge difference to the world and might see it as the beginning of the media. Pieces of pottery with marks on that are probably numbers have been discovered in China (31) _______ date from around 4000 BC. Hieroglyphics and other forms of "picture writing" developed in the area around Mesopotamia (modern-day Iraq), where the ancient Sumerian civilization was based, from around 3300 BC onwards. However, the first (32) _______ alphabet was used by the Phoenicians around 1050 BC. Their alphabet had 22 letters and it is estimated that it lasted for 1000 years. The first two signs were called "aleph" and "beth", which in Greek became "alpha" and "beta", which gave us the modern word "alphabet". The modern European alphabet is based on the Greek and spread (33) _______ other European countries under the Romans. A number of changes took place as time passed. The Romans added the letter G, and the letter J and V were unknown to people in Shakespeare's time. If we (34) _______ the history of punctuation, we also find some interesting facts. The Romans used to write quaesto at the end of a sentence in order to show that it was a Question. They started to write Qo in place of the whole word, and then put the Q above the o. In the end, that became the question mark "?" Điền vào ô trống 34

Xem chi tiết 767 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 word or phrase that best fits each of the numbered blanks. THE HISTORY OF WRITING The development of writing (30) _______ a huge difference to the world and might see it as the beginning of the media. Pieces of pottery with marks on that are probably numbers have been discovered in China (31) _______ date from around 4000 BC. Hieroglyphics and other forms of "picture writing" developed in the area around Mesopotamia (modern-day Iraq), where the ancient Sumerian civilization was based, from around 3300 BC onwards. However, the first (32) _______ alphabet was used by the Phoenicians around 1050 BC. Their alphabet had 22 letters and it is estimated that it lasted for 1000 years. The first two signs were called "aleph" and "beth", which in Greek became "alpha" and "beta", which gave us the modern word "alphabet". The modern European alphabet is based on the Greek and spread (33) _______ other European countries under the Romans. A number of changes took place as time passed. The Romans added the letter G, and the letter J and V were unknown to people in Shakespeare's time. If we (34) _______ the history of punctuation, we also find some interesting facts. The Romans used to write quaesto at the end of a sentence in order to show that it was a Question. They started to write Qo in place of the whole word, and then put the Q above the o. In the end, that became the question mark "?" Điền vào ô trống 33

Xem chi tiết 3.3 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 word or phrase that best fits each of the numbered blanks. THE HISTORY OF WRITING The development of writing (30) _______ a huge difference to the world and might see it as the beginning of the media. Pieces of pottery with marks on that are probably numbers have been discovered in China (31) _______ date from around 4000 BC. Hieroglyphics and other forms of "picture writing" developed in the area around Mesopotamia (modern-day Iraq), where the ancient Sumerian civilization was based, from around 3300 BC onwards. However, the first (32) _______ alphabet was used by the Phoenicians around 1050 BC. Their alphabet had 22 letters and it is estimated that it lasted for 1000 years. The first two signs were called "aleph" and "beth", which in Greek became "alpha" and "beta", which gave us the modern word "alphabet". The modern European alphabet is based on the Greek and spread (33) _______ other European countries under the Romans. A number of changes took place as time passed. The Romans added the letter G, and the letter J and V were unknown to people in Shakespeare's time. If we (34) _______ the history of punctuation, we also find some interesting facts. The Romans used to write quaesto at the end of a sentence in order to show that it was a Question. They started to write Qo in place of the whole word, and then put the Q above the o. In the end, that became the question mark "?" Điền vào ô trống 32

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 43 to 50.   In addition to improved physical health, sport plays a primarily positive role in youth development, including improved academic achievement, higher self- esteem, fewer behavioural problems, and better psychosocial development. Many studies focus on the effects of sport on the five “C’ s” - competence, confidence, connections, character, and caring The many facets of playing sport - the discipline of training, learning teamwork, following the leadership of coaches and captains, learning to lose - provide lifelong skills for athletes.   The literature on youth sport stresses the positive effects of participation in learning the important life skills of goal setting and time management combined with enjoyment; the development of a strong sense of morality; and the development of an appreciation of diversity. Studies have shown that children and youth participating in sport, when compared to peers who do not play sport, exhibit higher grades, expectations, and attainment; greater personal confidence and self-esteem; greater connections with school — that is, greater attachment and support from adults; stronger peer relationships; more academically oriented friends; greater family attachment and more frequent interactions with parents; more restraint in avoiding risky behaviour; and greater involvement in volunteer work.   Sport provides opportunities for children and youth to engage in valuable and positive relationships with adults. Thus, it is a missed opportunity for children who are “gated” - or not included in sport - during early stages of childhood because they are less well behaved than other children. These children are being prevented from participating in the very thing that could help them learn to control and regulate their behaviour. Sport provides an opportunity for children to safely navigate and negotiate between right and wrong as they learn to interact with peers and adults. Research by Taliaferro et al. suggests that playing sport can even protect against suicide risk in youth. Compared to nonathletes, male athletes exhibit lower levels of hopelessness and suicidal ideation. Young males involved in multiple sports seem to gamer even more protection in this regard. Similar results were found for girls. Research on the role of exercise in adults confirms that it improves mood and alleviates many forms of depression. Bartko and Eccles found that youth who are highly involved in sport are more “psychologically resilient,” that is, better able to recover from problems. Eccles et al. found that sport participation protects young athletes against social isolation. (Adaptedfrom: Sport is a way of life, Sun Star Baguio, Jan 10, 2017)  According to the passage what is NOT increased by playing sports?      

Xem chi tiết 522 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 word or phrase that best fits each of the numbered blanks. THE HISTORY OF WRITING The development of writing (30) _______ a huge difference to the world and might see it as the beginning of the media. Pieces of pottery with marks on that are probably numbers have been discovered in China (31) _______ date from around 4000 BC. Hieroglyphics and other forms of "picture writing" developed in the area around Mesopotamia (modern-day Iraq), where the ancient Sumerian civilization was based, from around 3300 BC onwards. However, the first (32) _______ alphabet was used by the Phoenicians around 1050 BC. Their alphabet had 22 letters and it is estimated that it lasted for 1000 years. The first two signs were called "aleph" and "beth", which in Greek became "alpha" and "beta", which gave us the modern word "alphabet". The modern European alphabet is based on the Greek and spread (33) _______ other European countries under the Romans. A number of changes took place as time passed. The Romans added the letter G, and the letter J and V were unknown to people in Shakespeare's time. If we (34) _______ the history of punctuation, we also find some interesting facts. The Romans used to write quaesto at the end of a sentence in order to show that it was a Question. They started to write Qo in place of the whole word, and then put the Q above the o. In the end, that became the question mark "?" Điền vào ô trống 31

Xem chi tiết 636 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 word or phrase that best fits each of the numbered blanks. THE HISTORY OF WRITING The development of writing (30) _______ a huge difference to the world and might see it as the beginning of the media. Pieces of pottery with marks on that are probably numbers have been discovered in China (31) _______ date from around 4000 BC. Hieroglyphics and other forms of "picture writing" developed in the area around Mesopotamia (modern-day Iraq), where the ancient Sumerian civilization was based, from around 3300 BC onwards. However, the first (32) _______ alphabet was used by the Phoenicians around 1050 BC. Their alphabet had 22 letters and it is estimated that it lasted for 1000 years. The first two signs were called "aleph" and "beth", which in Greek became "alpha" and "beta", which gave us the modern word "alphabet". The modern European alphabet is based on the Greek and spread (33) _______ other European countries under the Romans. A number of changes took place as time passed. The Romans added the letter G, and the letter J and V were unknown to people in Shakespeare's time. If we (34) _______ the history of punctuation, we also find some interesting facts. The Romans used to write quaesto at the end of a sentence in order to show that it was a Question. They started to write Qo in place of the whole word, and then put the Q above the o. In the end, that became the question mark "?" Điền vào ô trống 30

Xem chi tiết 1.1 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 43 to 50.   In addition to improved physical health, sport plays a primarily positive role in youth development, including improved academic achievement, higher self- esteem, fewer behavioural problems, and better psychosocial development. Many studies focus on the effects of sport on the five “C’ s” - competence, confidence, connections, character, and caring The many facets of playing sport - the discipline of training, learning teamwork, following the leadership of coaches and captains, learning to lose - provide lifelong skills for athletes.   The literature on youth sport stresses the positive effects of participation in learning the important life skills of goal setting and time management combined with enjoyment; the development of a strong sense of morality; and the development of an appreciation of diversity. Studies have shown that children and youth participating in sport, when compared to peers who do not play sport, exhibit higher grades, expectations, and attainment; greater personal confidence and self-esteem; greater connections with school — that is, greater attachment and support from adults; stronger peer relationships; more academically oriented friends; greater family attachment and more frequent interactions with parents; more restraint in avoiding risky behaviour; and greater involvement in volunteer work.   Sport provides opportunities for children and youth to engage in valuable and positive relationships with adults. Thus, it is a missed opportunity for children who are “gated” - or not included in sport - during early stages of childhood because they are less well behaved than other children. These children are being prevented from participating in the very thing that could help them learn to control and regulate their behaviour. Sport provides an opportunity for children to safely navigate and negotiate between right and wrong as they learn to interact with peers and adults. Research by Taliaferro et al. suggests that playing sport can even protect against suicide risk in youth. Compared to nonathletes, male athletes exhibit lower levels of hopelessness and suicidal ideation. Young males involved in multiple sports seem to gamer even more protection in this regard. Similar results were found for girls. Research on the role of exercise in adults confirms that it improves mood and alleviates many forms of depression. Bartko and Eccles found that youth who are highly involved in sport are more “psychologically resilient,” that is, better able to recover from problems. Eccles et al. found that sport participation protects young athletes against social isolation. (Adaptedfrom: Sport is a way of life, Sun Star Baguio, Jan 10, 2017)  What is NOT mentioned as a factor contributing to lifelong skills for athletes?      

Xem chi tiết 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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. In the second paragraph, the author mentions sun tanning as an example of _______ 

Xem chi tiết 297 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 540 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 author views body building _______ .

Xem chi tiết 1.2 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 1.3 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 bold refers to _______ .

Xem chi tiết 626 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 phrase “wither away” in bold is closest in meaning to _______ .

Xem chi tiết 1.4 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 question from 18 to 25. The principle of use and disuse states that those parts of organisms' bodies that are used grown 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 dimish. By examining a man's body, we can tell which muscles he uses and which he doesn't. We may even be able to guess his profession or his reaction. 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 and rickets. 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 1.6 K lượt xem 5 năm trước