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Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 39: The word “it” refers to:

A. a plant

B. an animal

C. bioluminescence

D. incandescence

1
21 tháng 9 2019

Đáp án C

Dịch nghĩa: Từ “it” để cập đến

A. một loài cây

B. một loài động vật

C. sự phát quang sinh học

D. sự cháy

Giải thích: Đọc câu đầu bài viết: “Light from a living plant or animal is called biolumines - cence, or cold light, to distinguish it from incandescence. . .” - “Ánh sáng từ một loài động hay thực vật còn sống được gọi là sự phát quang sinh học, hay ánh sáng lạnh, để phân biệt nó với sự cháy...”

25 tháng 8 2018

Đáp án: C

7 tháng 10 2019

Đáp án: B

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 36: Which of the following is the main topic of the passage?

A. Cold light

B. Luciferase

C. Primitive plants and animals

D. Earth’s atmosphere

1
22 tháng 2 2019

Đáp án A

Dịch nghĩa: Chủ đề chính của bài viết là gì?

A. Ánh sáng lạnh

B. Luciferase

C. Thực vật và động vật nguyên thủy

D. Khi hậu trên trái đất

Giải thích: Ta thấy đoạn văn chủ yếu nói về bioluminescence (sự phát quang sinh học) hay còn gọi là cold light (ánh sáng lạnh)

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 42: The paragraph following the passage most probably discuss ______.

A. incandescence in prehistoric plants and animals

B. incandescence in modern plants and animals

C. bioluminescence in prehistoric plants and animals

D. bioluminescence in modern plants and animals

1
4 tháng 1 2020

Đáp án D

Dịch nghĩa: Đoạn văn tiếp theo bài viết có thể nói về

A. sự cháy trong động thực vật tiền sử

B. sự cháy trong động thực vật đương đại

C. sự phát quang sinh học trong động thực vật tiền sử

D. sự phát quang sinh học trong động thực vật đương đại

Giải thích: Câu cuối bài viết: “...but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey” - “nhưng một số loài động thực vật nguyên thủy vẫn tiếp tục sử dụng ánh sáng với những chức năng mới như tìm bạn đời hay hấp dẫn con mồi.”

=> Có thể hiểu đoạn văn tiếp theo sẽ tiếp tục thảo luận về sự phát quang sinh học của những loài sinh vật này trong thời hiện đại.

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 40: Where in the passage does the author explain how living light occurs?

A. Line 3-4

B. Line 5-7

C. Line 8-l0

D. Line 10-12

1
21 tháng 2 2018

Đáp án B

Dịch nghĩa: Ở đâu trong đoạn văn tác giả giải thích ánh sáng tự nhiên tồn tại như thế nào?

A. Dòng 3-4

B. Dòng 5-7

C. Dòng 8-10

D. Dòng 10-12

Giải thích: Thông tin nằm ở dòng 5-7 đoạn văn: “Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required” - “Ánh sáng sống diễn ra khi luciferin và oxy kết hợp với sự có mặt của luciferase. Trong một số ít trường hợp, phổ biến nhất đối với đom đóm, cần một chất hóa học khác là ATP.”

=> Có thể thấy trong 2 câu này tác giả đã giải thích quá trình hình thành của ánh sáng sống.

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 41: Bioluminescence is described as all of the following EXCEPT ______.

A. a complex chemicals process

B. an adaptation of early plants and animals to the environment

C. a form of cold light

D. a poisonous substance

1
16 tháng 11 2018

Đáp án D

Dịch nghĩa: Sự phát quang sinh học được miêu tả như tất cả những điều sau NGOẠI TRỮ _______.

A. một quá trình hóa học phức tạp

B. một sự thích ứng của những loài động thực vật tiền sử với môi trường

C. một dạng ánh sáng lạnh

D. một chất có độc

Giải thích: Ta thấy các đáp án còn lại đều được nói đến như những đặc tính của sự phát quang sinh học:

A. Đoạn 1: “Although bioluminescence is a relatively complicated process, it can be reduced to simple terms” - “Mặc dù sự phát quang sinh học là một quá trình tương đối phức tạp, nó có thể được giảm xuống đến những khái niệm đơn giản.”

B. Đoạn cuối: “It is speculated that millions of years ago, all life may have produced light to survive” - “Người ta đoán rằng hàng triệu năm về trước, toàn bộ sự sống có thể đã phải tạo ra ánh sáng để sinh tồn.”

C. Câu đầu bài viết: “Light from a living plant or animal is called bioluminescence, or cold light...” - “Ánh sáng từ một loài động vật hay thực vật còn sống được gọi là sự phát quang sinh học, hay ánh sáng lạnh. . .”

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question 37: According to the author, why has bioluminescence continued in modern plants and animals?

A. For survival

B. For attracting prey

C. For producing heat

D. For burning excess oxygen

1
26 tháng 8 2018

Đáp án B

Dịch nghĩa: Theo tác giả, tại sao sự phát quang sinh học lại tiếp diễn đối với thực và động vật hiện đại?

A. Để sinh tồn

B. Để hấp dẫn con mồi

C. Để sản sinh nhiệt

D. Để đốt cháy oxy thừa

Giải thích: Thông tin nằm ở “. . .but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey” - “nhưng một số loài động thực vật nguyên thủy vẫn tiếp tục sử dụng ánh sáng với những chức năng mới như tìm bạn đời hay hấp dẫn con mồi.”

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. It is estimated that by 2050 more than two-thirds of the world's population will live in cities, up from about 54 percent today. While the many benefits of organized and efficient cities are well understood, we need to recognize that this rapid, often unplanned urbanization brings risks of profound social instability, risks to critical...
Đọc tiếp

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.
 
It is estimated that by 2050 more than two-thirds of the world's population will live in cities, up from about 54 percent today. While the many benefits of organized and efficient cities are well understood, we need to recognize that this rapid, often unplanned urbanization brings risks of profound social instability, risks to critical infrastructure, potential water crises and the potential for devastating spread of disease. These risks can only be further exacerbated as this unprecedented transition from rural to urban areas continues.
How effectively these risks can be addressed will increasingly be determined by how well cities are governed. The increased concentration of people, physical assets, infrastructure and economic activities mean that the risks materializing at the city level will have far greater potential to disrupt society than ever before.
Urbanization is by no means bad by itself. It brings important benefits for economic, cultural and societal development. Well managed cities are both efficient and effective, enabling economies of scale and network effects while reducing the impact on the climate of transportation. As such, an urban model can make economic activity more environmentally-friendly. Further, the proximity and diversity of people can spark innovation and create employment as exchanging ideas breeds new ideas.
But these utopian concepts are threatened by some of the factors driving rapid urbanization. For example, one of the main factors is rural-urban migration, driven by the prospect of greater employment opportunities and the hope of a better life in cities. But rapidly increasing population density can create severe problems, especially if planning efforts are not sufficient to cope with the influx of new inhabitants. The result may, in extreme cases, be widespread poverty. Estimates suggest that 40% of the world's urban expansion is taking place in slums, exacerbating socio-economic disparities and creating unsanitary conditions that facilitate the spread of disease.
The Global Risks 2015 Report looks at four areas that face particularly daunting challenges in the face of rapid and unplanned urbanization: infrastructure, health, climate change, and social instability. In each of these areas we find new risks that can best be managed or, in some cases, transferred through the mechanism of insurance.
Question 36: The word “that" in paragraph 4 refers to __________.
​A. urban expansion ​​B. socio-economic disparities
​C. disease  ​D. unsanitary conditions
Question 37:According to paragraph 3, what is one of the advantages of urbanization?
​A. It minimizes risks for economic, cultural and societal development.
​B. It makes water supply system both efficient and effective.  
​C. Weather and climate in the city will be much improved.
​D. People may come up with new ideas for innovation.
Question 38:Which statement is TRUE, according to the passage?
​A. Urbanization brings important benefits for development as well.
​B. 54% of the world's population will live in cities by 2050.
​C. Risks cannot be addressed effectively no matter how well cities are governed.
​D. Rapidly increasing population density can help solve poverty.
Question 39: The word "addressed" in paragraph 2 is closest in meaning to _________.
​A. aimed at ​B. dealt with ​C. added to ​D. agreed on
Question 40: What can be inferred from the passage?
​A. Poverty may be a foregone conclusion of unplanned urbanization.
​B. Diseases are caused by people migrating to cities.  
​C. Urbanization can solve the problem of environmental pollution in cities.
​D. The increasing number of people in cities can create more employment.
Question 41: Which is the most suitable title for the passage?
​A. The Risks of Rapid Urbanization in Developing Countries
​B. Infrastructure and Economic Activities in Cities
​C. The Global Risks 2015 Report on Developing Urban Areas
​D. Rapid Urbanization Put Cities in Jeopardy
Question 42: The word “spark” in paragraph 3 is closest in meaning to ___________.
​A. need ​B. start ​C. encourage ​D. design

1
17 tháng 6 2021

Question 36: The word “that" in paragraph 4 refers to __________.
​A. urban expansion ​​B. socio-economic disparities
​C. disease  ​D. unsanitary conditions
Question 37:According to paragraph 3, what is one of the advantages of urbanization?
​A. It minimizes risks for economic, cultural and societal development.
​B. It makes water supply system both efficient and effective.  
​C. Weather and climate in the city will be much improved.
​D. People may come up with new ideas for innovation.
Question 38:Which statement is TRUE, according to the passage?
​A. Urbanization brings important benefits for development as well.
​B. 54% of the world's population will live in cities by 2050.
​C. Risks cannot be addressed effectively no matter how well cities are governed.
​D. Rapidly increasing population density can help solve poverty.
Question 39: The word "addressed" in paragraph 2 is closest in meaning to _________.
​A. aimed at ​B. dealt with ​C. added to ​D. agreed on
Question 40: What can be inferred from the passage?
​A. Poverty may be a foregone conclusion of unplanned urbanization.
​B. Diseases are caused by people migrating to cities.  
​C. Urbanization can solve the problem of environmental pollution in cities.
​D. The increasing number of people in cities can create more employment.
Question 41: Which is the most suitable title for the passage?
​A. The Risks of Rapid Urbanization in Developing Countries
​B. Infrastructure and Economic Activities in Cities
​C. The Global Risks 2015 Report on Developing Urban Areas
​D. Rapid Urbanization Put Cities in Jeopardy
Question 42: The word “spark” in paragraph 3 is closest in meaning to ___________.
​A. need ​B. start ​C. encourage ​D. design

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42. Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed....
Đọc tiếp

Read the following passage and mark the letter A, B, C or D to indicate the correct answer to each of the questions from 36 to 42.

Light from a living plant or animal is called bioluminescence, or cold light, to distinguish it from incandescence or heat-generating light. Life forms could not produce incandescent light without being burned. Their light is produced in chemicals combining in such a way that little or no measurable heat is produced, and the life forms generating it are unharmed. Although bioluminescence is a relatively complicated process, it can be reduced to simple terms. Living light occurs when luciferin and oxygen combine in the presence of luciferase. In a few cases, fireflies the most common, an additional compound called ATP is required.

The earliest recorded experiments with bioluminescence in the late 1800s are attributed to Raphael Dubois, who extracted a luminous fluid from a clam, observing that it continued to glow in the test tube for several minutes. He named the substance luciferin, which means “the bearer of life”. In further research, Dubois discovered that several chemicals were required for bioluminescence to occur. In his notes, it was recorded that a second important substance, which he called luciferase, was always present. In later study of small, luminous sea creatures, Newton Harley concluded that luciferin was composed of carbon, hydrogen, and oxygen, which are the building blocks of all living cells. He also proved that there are a variety of luciferin and luciferase, specific to the plants and animals that produce them.

Much remains unknown, but many scientists who are studying bioluminescence now believe that the origin of the phenomenon may be traced to a time when there was no oxygen in the Earth’s atmosphere. When oxygen was gradually introduced to the atmosphere, it was actually poisonous to life forms, plants and animals produced light to use up the oxygen in a gradual but necessary adaptation. It is speculated that millions of years ago, all life may have produced light to survive. As the millennia passed, life forms on Earth became tolerant of, and finally dependent on oxygen, and the adaptation that produced bioluminescence was no longer necessary, but some primitive plants and animals continued to use the light for new functions such as mating or attracting prey.

Question38: The word “primitive” is closest meaning to ______.

A. very old

B. very large

C. very important

D. very common

1
24 tháng 3 2017

Đáp án A

Dịch nghĩa: Từ “primitive” gần nghĩa nhất với _______.

A. rất nhiều tuổi

B. rất lớn

C. rất quan trọng

D. rất phổ biến

Giải thích: be primitive: rất lâu đời, nguyên thủy = very old

22 tháng 4 2019

Đáp án: D