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.

GLOBAL WARMING

Few people now question the reality of global warming and its effects on the world's climate. Many scientists (1) _____________the blame for recent natural disasters on the increase in the world's temperatures and are convinced that, more than ever before, the Earth is at risk from the forces of the wind, rain and sun. According to them, global warming is making extreme weather events, such as hurricanes and droughts, even more (2) _____________and causing sea levels all around the world to rise.

     Environmental groups are putting pressure on governments to take action to reduce the amount of carbon dioxide which is given (3) _____________by factories and power plants, thus attacking the problem at its source. They are in favor of more money being spent on research into solar, wind and wave energy devices, (4) _____________ could then replace existing power station.

Some scientists, (5) _____________, believe that even if we stopped releasing carbon dioxide and other gases into the atmosphere tomorrow, we would have to wait several hundred years to notice the results. Global warming, it seems, is to stay.

(3) _________

Read the text below and decide which answer (A,B,C, or D) best fits each space.
Postsecondary institutions and private schools are corporations under U.S. law.  They are approved to operate as non-profit, for-profit, or public corporations (1)  _______ education and training. Increasingly, state authorities are requiring  approved educational providers to apply (2) _______ and receive accreditation  as a condition of final and continued approval. 
As corporate entities, U.S. institutions are internally self-governing and are (3)  _______ to make property, facilities, equipment, and utilities transactions; make  their own personnel decisions; decide whom to admit to study and to graduate;  (4) _______ their own funds from outside sources; enter into contracts and  compete for grants; and do most of the other things that corporations do.  Institutions compete (5) _______ one another for students, research funding,  faculty, and other benefits. Public institutions may compete within the same  state or territory for budget appropriations. It is the corporate nature of  institutions and the competition within the system that (6) _______ Americans  to refer to the concept of the educational or academic marketplace - an important distinctive element of the way U.S. education is organized. 
Some institutions are governed (7) _______ under multi-campus arrangements.  These include most local public schools (governed by school districts) and many  state community college and university systems. Whether single- or multi campus, institutional corporations (8) _______ by boards of citizens, both  alumni and non- alumni, who are ultimately responsible for all operations. They  appoint senior (9) _______, such as principals, headmasters, presidents, and  deans; and approve the actions taken (10) ______ their name. 

3.....................

Read the following passage and mark the letter A, B, C, or D to indicate the correct word or phrase that best fits each the numbered blanks. 
At present, single-parent families ought to be of great focus, be recognized and supported as they are a growing family form and should not be an afterthought in family, economic and labor market policies. Single parent families should be (25) _______ considered and addressed in all family policy discussions and decisions. (26)________, home-care cash allowances, which are paid to a parent who abstains from employment to take care for her child at home, can have significant consequences encouraging lower levels of female employment among single-parent families, (27)________ in turn results in higher childhood poverty. In this regard, work-life balance policies and workplace practices also need to (28)________ a single-parent perspective, for example, the impact of non-standard work hours when childcare is not available.
The provision of educational and skill-building opportunities and affordable quality day care become even more urgent in families with single parents. Such families should have a higher priority and subsidized access to childcare facilities. Governmental agencies should be established (29)________ child support payment from non-resident parents in case of conflicts, disagreements or delayed payments, e.g., after a divorce or separation.

In this regard, work-life balance policies and workplace practices also need to (28)________ a single-parent perspective, for example, the impact of non-standard work hours when childcare is not available.

Read the text below and decide which answer (A,B,C, or D) best fits each space.
MY FIRST JOB

When I was 19, I (58) …….. out of my university course and ended up getting a job in a local travel agent’s. I’d seen the (59) …….. for the job in local paper. It said they wanted someone with a nice (60) …….. and a friendly (61) …….. .I thought the job might be an (62) …….. to send people to interesting places and to see some of the world myself. (63) …….. , it turned out to be a bit of a joke. I arrived at work on the first day with a positive (64) …….., ready to work and learn about new places. I spent that morning and every morning for the first three months filling (65)…….. forms and making coffee for the rest of the staff. (66) …….. I was hoping to be dealing with travel-hungry people with a good idea of where they wanted to go, the (67) …….. customer took ages to make their mind (68) …….. . It was amazing the number  of  customers  who  would  spend  ages  finding  the  perfect  destination  only  to have a change (69) …….. heart at the last moment. If we did organize the trip of a lifetime for someone, we rarely got thanks (70) …….. all our efforts. I now work in publishing (71) …….. a living, so these days I’m a customer in travel agencies. One thing I always keep (72) …….. mind is the need to say thank you.

61...................

Read the passage below and choose one correct answer for each question.

Books which give instructions on how to do things are very popular in the United States today. Thousands of these How-to books are useful: in fact, there are about four thousand books with titles that begin with the words 'How-to". One book may tell you how to earn more money, another may tell you how to save or spend it and another may explain how to give your money away. Many How-to books give advice on careers. They tell you how to choose a career and how to succeed in it. If you fail, however, you can buy the book “How to Turn Failure into Success”. If you would like to become very rich, you can buy the book “How to Make a Millionaire”. If you never make any money at all. you may need abook called “How to Live on Nothing”. One of the most popular types of books is one that helps you with personal problems. If you want to have a better love of life, you can read “How to Succeed in Love Every Minute of Your Life”. If you are tired of books on happiness,  you may prefer books which give step-by-step instructions on how to redecorate or enlarge a house. Why have How-to books become so popular? Probably because life has become so complex. Today people have far more time to use, more choices to make, and more problems to solve. How-to books help people deal with modern life.

From the first paragraph, we know How-to books are________.

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 36 to 40.
Vietnamese generally shake hands when greeting and parting. Using both hands shows respect as does a (36)_________ bow of the head. In rural areas, elderly people who do not extend their hand are greeted with a slight bow. Women are more likely to bow the head than to shake hands. Vietnamese names begin with the family name andare (37)_________ by a given name. People address one another by their given names,    but add a title that indicates their perceived relationship to the other person. These titles are family related rather than professional. Among colleagues, for example, the younger of the two might combine the given name with the title of - Anh(OlderBrother). A/n (38)_________ greeting combined with the given name and titleis “Xin chao” (Hello). Classifiers for gender and familiarity are also combined with the greeting. In formal meetings, business cards are sometimes exchanged on greeting.
Vietnamese have astrong (39)_________ of hospitality and feel embarrassed if they cannot show their guests  full respect by preparing for their arrival. Therefore, it is (40)_________ to visit someone without having been invited. Gifts are not required, but are appreciated. Flowers, incense, or tea may be appropriate gifts for the hosts. Hosts also appreciate a small gift for their children or elderly parents.
(37).................

Course numbers are an indication of which courses are to various categories of students at the University. Undergraduate courses with the numbers 100 or 200 are generally introductory courses appropriate for freshmen or sophomores, whereas courses with the numbers 300 or 400 often have prerequisites and are often to juniors and seniors only. Courses with the numbers 800 or above are open only to graduate students. ​Certain graduate courses, generally those devoted to introductory material, are numbered 400 for undergraduate students who qualify to take them and 600 for graduate students. Courses designed for students seeking a professional degree carry a 500 number for undergraduate students and a 700 number for graduate students. Courses numbered 99 or below are special interest courses that do not carry academic credit. If students elect to take a special interest course, it will not count toward the number of hours needed to complete graduation requirements.
Full - time undergraduate student is expected to take courses that total twelve to eighteen credit hours. A full-time graduate student is expected to take courses that total ten to sixteen credit hours. Student holding assistantships are expected to enroll for proportionately fewer hours. A part - time graduate may register for minimum of three credit hours. An overload, that is, more than the maximum number of hours, may be taken with the approval of an academic advisor. To register for an overload, students must submit the appropriate approval form when registering. Overloads above 24 hours will not be approved under any circumstances.

Which classification of students would be eligible to enroll in Mechanical Engineering 850?

Choose the word or phrase among A, B, C or D that best fits the blank space in the following passage:

"Many parents believe that they should begin to teach their children to read when they are (1)….. more than toddlers. This is fine if the child shows a real interest but (2)…… a child could be counter-productive if he isn’t ready. Wise parents will have a (3)….. attitude and take the lead from their child. What they should provide is a selection of (4)….. toys, books and other activities. Nowadays there is a plenty of good (5)….. available for young children, and of course, seeing plenty of books in use about the house will also (6)…..  them to read.
 Of course, books are no longer the only (7)….. of stories and information. There is also a huge range of videos, which can (8)…. And extend the pleasure a child finds in a book and are (9)… valuable in helping to increase vocabulary and concentration. Television gets a bad (10)…. as far as children are concerned, mainly because too many children spend too much time watching programmes not intended for their age group."

8. There is also a huge range of videos, which can (8)….

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.

   Telecommuting is a form of computer communication between employees’ homes and offices. For employees whose jobs involve sitting at a terminal or word processor entering data or typing reports, the location of the computer is of no consequence. If the machine can communicate over telephone lines, when the work is completed, employees can dial the office computer and transmit the material to their employers. A recent survey in USA Today estimates that there are approximately 8,7 million telecommuters. But although the numbers are rising annually, the trend does not appear to be as significant as predicted when Business Week published “The Portable

   Executive” as its cover story a few years ago. Why hasn’t telecommuting become more popular ?

   Clearly, change simply takes time. But in addition, there has been active resistance on the part of many managers. These executives claim that supervising the telecommuters in a large work force scattered across the country would be too difficult, or, at least, systems for managing them are not yet developed, thereby complicating the manager’s responsibilities.

   It is also true that employees who are given the option of telecommuting are reluctant to accept the opportunity. Most people feel that they need regular interaction with a group, and many are concerned that they will not have the same consideration for advancement if they are not more visible in the office setting. Some people feel that even when a space in their homes is set aside as a work area, they never really get away from the office.

It can be inferred from the passage that the author is ___________.

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.

   One day in 1924, five men who were camping in the Cascade Mountains of Washington saw a group of huge apelike creatures coming out of the woods. They hurried back to their cabin and locked themselves inside. While they were in, the creatures attacked them by throwing rocks against the walls of the cabin.

   After several hours, these strange hairy giants went back into the woods. After this incident the men returned to the town and told the people of their adventure. However, only a few people accepted their story. These were the people who remembered hearing tales about footprints of an animal that walked like a human being.

   The five men, however, were not the first people to have seen these creatures called Bigfoot. Long before their experience, local Native Americans were certain that a race of apelike animals had been living in the neighboring mountain for centuries. They called these creatures Sasquatch.

   In 1958, workmen, who were building a road through the jungles of Northern California often found huge footprints in the earth around their camp.

   Then in 1967, Roger Patterson, a man who was interested in finding Bigfoot went into the Northern California jungles with a friend. While riding, they were suddenly thrown off from their horses. Patterson saw a tall apelike animal standing not far away. He managed to shoot seven rolls of film of the hairy creature before the animal disappeared in the hushes. when Patterson's film was shown to the public, not many people believed his story.

   In another incident, Richard Brown, a music teacher and also an experienced hunter spotted a similar creature. He saw the animal clearly through the telescopic lens of his rifle. He said the creature looked more like a human than an animal.

   Later many other people also found deep footprints in the same area. In spite of regular reports of sightings and footprints, most experts still do not believe that Bigfoot really exists.

The BEST title for this passage would be

Read the following passage and choose the correct answer to each of the questions.

The word "robot" first appeared in a 1921 stage play by Czech writer Karel Capek. In the play, a man makes a machine that can think, which he calls a robot and which ends up killing its owner. In the 1940s, the American science fiction writer, Isaac Asimov, wrote a series of stories about robots and invented the term 'robotics', the science of robots. Meanwhile, in the real world, the first robots were developed by an engineer, Joseph F. Engelberger, and an inventor, George C. Devol. Together they started Unimation, a manufacturing company that produced the first real robot in 1961, called the Unimate. Robots of this type were installed at a General Motors automobile plant and proved to be a success. They worked reliably and saved money for General Motors, so other companies were soon acquiring robots as well.

These industrial robots were nothing like the terrifying creatures that can often be seen in science fiction films. In fact, these robots looked and behaved nothing like humans. They were simply pieces of computer-controlled machines, with metal "arms" or "hands". Since they were made of metal, they could perform certain jobs that were difficult or dangerous for humans, particularly jobs that involve high heat. And since robots were tireless and never got hungry, sleepy, or distracted, they were useful for tasks that would be tiring or boring for humans. Industrial robots have been improved over the years, and today they are used in many factories around the world. Though the use of robots has meant the loss of some jobs, at the same time other jobs have been created in the design, development, and production of the robots.

Outside of industry, robots have also been developed and put into use by governments and scientists in situations where humans might be in danger. For example, they can be sent in to investigate an unexploded bomb or an accident at a nuclear power plant. Researchers also use robots to collect samples of hot rocks or gases in active volcanoes. In space exploration, robots have performed many key tasks where humans could not be present, such as on the surface of Mars. In 2004, two robotic Rovers, small six-wheeled computerized cars, were sent to Mars.

What does the word they in paragraph 2 refer to?

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word(s) for each of the blanks from 41 to 45.
The United States has many different types of families. While most American families are traditional,(41)_________ a father, mother and one or more children, 22 percent of all American families in 1998 were headed by one parent, usually a woman. In a few families in the United States, there are no children. These childish couples may believe that they would not make good parents; they may want freedom from the (42)_________ of childbrearing or, perhaps they (43)_________ physically able to have children. Other families in the United States have one adult (44)_________ a stepparent. A stepmother or stepfather is a       person who joins a family by marrying a father or mother Americans tolerate and accept these different types of families. In the United States, people have the right to privacy and Americans do not believe in telling other Americans what type of family group they must belong to. They respect each other’s (45) _________ regarding family groups. Families are very important to Americans.
(44)...................

Choose the letter A, B, C or D to answer these following questions:
If you want to prepare yourself for great achievement and have more to contribute to your education or your work, try reading more books. Pick up some of the interestingly informative books and search for well-researched material that can help you grow. 
We should encourage our children to read more books and spend less time watching TV. Some people have commented that this is inconsistent. "Why is the written word a superior way to get information than television?" That is an interesting point of view worth further exploration. Reading is a skill that is in much greater demand than the demand for watching TV. There are no jobs that require a person to be able to watch TV but reading is an integral part of many jobs. The written word is an incredibly flexible and efficient way of communication. You can write something down and, in no time, it can be sent to many different people. Not only that, we can digest vast amounts of information through reading in a very short time. A good reader can acquire more information in reading for two hours than someone watching TV can acquire in a full day. You are able to gain a lot of information quickly because you are a fast reader with good comprehension skills. It will save you massive amounts of time and you will be able to assimilate vast quantities of information.

What are the benefits of becoming good readers?

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.

   Marianne Moore (1887-1972) once said that her writing could be called poetry only because there was no other name for it. Indeed her poems appear to be extremely compressed essays that happen to be printed in jagged lines on the page. Her subjects were varied: animals, laborers, artists, and the craft of poetry. From her general reading came quotations that she found striking or insightful. She included these in her poems, scrupulously enclosed in quotation marks, and sometimes identified in footnotes. Of this practice, she wrote, "Why many quotation marks?" I am asked ... When a thing has been so well that it could not be said better, why paraphrase it? Hence, my writing is, if not a cabinet of fossils, a kind of collection of flies in amber." Close observation and concentration on detail and the methods of her poetry.

   Marianne Moore grew up in Kirkwood, Missouri, near St. Lois. After graduation from Bryn Mawr College in 1909, she taught commercial subjects at the Indian School in Carlisle, Pennsylvania. Later she became a librarian in New York City. During the 1920’s she was editor of

   The Dial, an important literary magazine of the period. She lived quietly all her life, mostly in Brooklyn, New York. She spent a lot of time at the Bronx Zoo, fascinated by animals. Her admiration of the Brooklyn Dodgers-before the team moved to Los Angeles-was widely known.

   Her first book of poems was published in London in 1921 by a group of friends associated with the Imagist movement. From that time on her poetry has been read with interest by succeeding generations of poets and readers. In 1952 she was awarded the Pulitzer Prize for her Collected Poems. She wrote that she did not write poetry for money or fame. To earn a living is needful, but it can be done in routine ways. One writes because one has a burning desire to objectify what it is indispensable to one's happiness to express.

The word "succeeding" is closest to ______.

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
An important point to remember if you like spending time out in the open air is that the human head doesn't work very well outdoors if it becomes too hot, cold or wet. That‟s why a hat is a  good investment, whenever you are planning to go out and about. Surprisingly, a single waterproof hat with a brim will do the (16)       adequately in most conditions.
In cold climates, the problem is that the head is (17)           heat all the time. As much as fifty to sixty per cent of your body‟s heat is lost through the head and neck, (18)      on which scientist  you believe. Clearly this heat loss needs to be prevented, but it‟s important to remember that hats don‟t actually keep you warm, they simply stop heat escaping.
Just as important is the need to protect your neck from the effects of bright sunlight, and the brim of your hat will do this. If you prefer a baseball cap, (19)       buying one that has a drop down tail at the back to stop your neck getting sunburnt.
And in wet weather  (20)         ,  hats are often more practical than  pooling up the hood of your waterproof coat because when you turn your head, the hat goes with you, whereas the hood usually does not.
(19)..........................

Read the following passage and mark the letter A, B, C or D on your answer sheet to indicate the correct word for each of the blanks from 36 to 40.
Vietnamese generally shake hands when greeting and parting. Using both hands shows respect as does a (36)_________ bow of the head. In rural areas, elderly people who do not extend their hand are greeted with a slight bow. Women are more likely to bow the head than to shake hands. Vietnamese names begin with the family name andare (37)_________ by a given name. People address one another by their given names,    but add a title that indicates their perceived relationship to the other person. These titles are family related rather than professional. Among colleagues, for example, the younger of the two might combine the given name with the title of - Anh(OlderBrother). A/n (38)_________ greeting combined with the given name and titleis “Xin chao” (Hello). Classifiers for gender and familiarity are also combined with the greeting. In formal meetings, business cards are sometimes exchanged on greeting.
Vietnamese have astrong (39)_________ of hospitality and feel embarrassed if they cannot show their guests  full respect by preparing for their arrival. Therefore, it is (40)_________ to visit someone without having been invited. Gifts are not required, but are appreciated. Flowers, incense, or tea may be appropriate gifts for the hosts. Hosts also appreciate a small gift for their children or elderly parents.
(40).................

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.

   Marianne Moore (1887-1972) once said that her writing could be called poetry only because there was no other name for it. Indeed her poems appear to be extremely compressed essays that happen to be printed in jagged lines on the page. Her subjects were varied: animals, laborers, artists, and the craft of poetry. From her general reading came quotations that she found striking or insightful. She included these in her poems, scrupulously enclosed in quotation marks, and sometimes identified in footnotes. Of this practice, she wrote, "Why many quotation marks?" I am asked ... When a thing has been so well that it could not be said better, why paraphrase it? Hence, my writing is, if not a cabinet of fossils, a kind of collection of flies in amber." Close observation and concentration on detail and the methods of her poetry.

   Marianne Moore grew up in Kirkwood, Missouri, near St. Lois. After graduation from Bryn Mawr College in 1909, she taught commercial subjects at the Indian School in Carlisle, Pennsylvania. Later she became a librarian in New York City. During the 1920’s she was editor of

   The Dial, an important literary magazine of the period. She lived quietly all her life, mostly in Brooklyn, New York. She spent a lot of time at the Bronx Zoo, fascinated by animals. Her admiration of the Brooklyn Dodgers-before the team moved to Los Angeles-was widely known.

   Her first book of poems was published in London in 1921 by a group of friends associated with the Imagist movement. From that time on her poetry has been read with interest by succeeding generations of poets and readers. In 1952 she was awarded the Pulitzer Prize for her Collected Poems. She wrote that she did not write poetry for money or fame. To earn a living is needful, but it can be done in routine ways. One writes because one has a burning desire to objectify what it is indispensable to one's happiness to express.

Which of the following can be inferred about Moore's poems?

Many of the most damaging and life-threaling types of weather-torrential rains, severe thunderstorms, and tornadoes-begin quickly, strike suddenly, and dissipate rapidly, devastating small regions while leaving neighboring areas untouched. One such event, a tornado, struck the northeastern section of Edmonton, Alberta, in July 1987. Total damages from the tornado exceeded $250 million, the highest ever for any Canadian storm. Conventional computer models of the atmosphere have limited value in predicting short-live local storms like the Edmonton tornado, because the available weather data are generally not detailed enough to allow computers to discern the subtle atmospheric changes that precede these storms. In most nations, for example, weather balloon observations are taken just once every twelve hours at locations typically separated by hundreds of miles. With such limited data, conventional forecasting models do a much better job predicting general weather conditions over large regions than they do forecasting specific local events.
Until recently, the observation-intensive approach needed for accurate, very short range forecasts, or “Nowcasts”, was not feasible. The cost of equipping and operating many thousands of conventional weather stations was prohibitively high, and the difficulties involved in rapidly collecting and processing the raw weather data from such a network were insurmountable. Fortunately, scientific and technological advances have overcome most of these problems. Radar systems, automated weather instruments, and satellites are all capable of making detailed, nearly continuous observation over large regions at a relatively low cost. Communications satellites can transmit data around the world cheaply and instantaneously, and modern computers can quickly compile and analyzing this large volume of weather information. Meteorologists and computer scientists now work together to design computer programs and video equipment capable of transforming raw weather data into words, symbols, and vivid graphic displays that forecasters can interpret easily and quickly. As meteorologists have begun using these new technologies in weather forecasting offices, Nowcasting is becoming a reality.

With which of the following statements is the author most likely to agree?

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.

Imagine you are buying an apple in a supermarket. Which do you choose, one with a small bro or one without? Be honest - you'd go for the apple (1) _________looks perfect. Supermarkets do this too on a much larger scale when buying fruit and vegetables from farmers. And what (2) ______of the on with marks on them? They are thrown away. So are the ones that are a funny shape or size.

(3) _______ reason for waste is that people buy more food than they can eat and supermarkets de everything they can to encourage this, for example with offers like 'Buy one, get one free'. Developed countries waste about 650 million tons of food each year and so do developing countries. (4) _____the waste happens for very different reasons. As the world's population grows, this problem will only (5) _________ so we need to take action urgently.

(Adapted from Navigate)

(3) ________

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.

   Marianne Moore (1887-1972) once said that her writing could be called poetry only because there was no other name for it. Indeed her poems appear to be extremely compressed essays that happen to be printed in jagged lines on the page. Her subjects were varied: animals, laborers, artists, and the craft of poetry. From her general reading came quotations that she found striking or insightful. She included these in her poems, scrupulously enclosed in quotation marks, and sometimes identified in footnotes. Of this practice, she wrote, "Why many quotation marks?" I am asked ... When a thing has been so well that it could not be said better, why paraphrase it? Hence, my writing is, if not a cabinet of fossils, a kind of collection of flies in amber." Close observation and concentration on detail and the methods of her poetry.

   Marianne Moore grew up in Kirkwood, Missouri, near St. Lois. After graduation from Bryn Mawr College in 1909, she taught commercial subjects at the Indian School in Carlisle, Pennsylvania. Later she became a librarian in New York City. During the 1920’s she was editor of

   The Dial, an important literary magazine of the period. She lived quietly all her life, mostly in Brooklyn, New York. She spent a lot of time at the Bronx Zoo, fascinated by animals. Her admiration of the Brooklyn Dodgers-before the team moved to Los Angeles-was widely known.

   Her first book of poems was published in London in 1921 by a group of friends associated with the Imagist movement. From that time on her poetry has been read with interest by succeeding generations of poets and readers. In 1952 she was awarded the Pulitzer Prize for her Collected Poems. She wrote that she did not write poetry for money or fame. To earn a living is needful, but it can be done in routine ways. One writes because one has a burning desire to objectify what it is indispensable to one's happiness to express.

Where did Moore spend most of her adult life?

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, hydrosen, 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.

Bioluminescence is described as all of the following EXCEPT ________.