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

"Before the 1960s, Singapore was essential a trading nation. Since (1)….. , it has developed a more (2)…. economy and has become an important financial, trade, and transportation center. Singapore has (3)….. banks, insurance, and finance companies, as (4) …..  as a stock exchange. Tourism is also important to the (5)…. of Singapore.
 There is (6)…. unemployment in Singapore. The country’s annual income per capita (per person) is one of the (7) …. in Asia. The government of Singapore plays a major role in the country’s economy. For example, it (8)….. what benefits, such as vacation time and sick leave, must be (9)….for workers by employers. It also operates an employment agency to help people find jobs, and it provides (10)…..  for retired workers."

1. Before the 1960s, Singapore was essential a trading nation. Since (1)….. , it has developed 

Since the dawn of time, people have found ways to communicate with one another. Smoke signals and tribal drums were some of the earliest forms of communication. Letters, carried by birds or by humans on foot or on horseback, made it possible for people to communicate larger amounts of information between two places. The telegram and telephone set the stage for more modern means of communication. With the invention of the cellular phone, communication itself has become mobile.
For you, a cell phone is probably just a device that you and your friends use to keep in touch with family and friends, take pictures, play games, or send text message. The definition of a cell phone is more specific: it is a hand- held wireless communication device that sends and receives signals by way of small special areas called cells.
Walkie - talkies, telephones and cell phones are duplex communication devices: They make it possible for two people to talk to each other. Cell phones and walkie- talkies are different from regular phones because they can be used in many different locations. A walkie- talkie is sometimes called a half- duplex communication device because only one person can talk at a time. A cell phone is a full- duplex device because it uses both frequencies at the same time. A walkie-talkie has only one channel. A cell phone has more than a thousand channels. A walkie- talkie can transmit and receive signals across a distance of about a mile. A cell phone can transmit and receive signals over hundreds of miles. In 1973, an electronic company called Motorola hired Martin Cooper to work on wireless communication. Motorola and Bell Laboratories (now AT& T) were in a race to invent the first portable communication device.
Martin Cooper won the race and became the inventor of the cell phone. On April 3, 1973, Cooper made the first cell phone call to his opponent at AT& T while walking down the streets of New York city. People on the sidewalks gazed at cooper in amazement. Cooper's phone was called A Motorola Dyna- Tac. It weighed a whopping 2.5 pounds (as compared to today's cell phones that weigh as little as 3 or 4 ounces)
After the invention of his cell phone, Cooper began thinking of ways to make the cell phone available to the general public. After a decade, Motorola introduced the first cell phone for commercial use. The early cell phone and its service were both expensive. The cell phone itself cost about $ 3, 500. In 1977, AT & T constructed a cell phone system and tried it out in Chicago with over 2, 000 customers. In 1981, a second cellular phone system was started in the Washington,D.C and Baltimore area. It took nearly 37 years for cell phones to become available for general public use. Today, there are more than sixty million cell phone customers with cell phones producing over thirty billion dollars per years.

The word “ they” in paragraph 2 refer to     .........

Choose the best answer: 
By the time we (1)________old age most of us have (2)________twenty years sleeping. Yet nobody knows why we do it. Most scientists believe that by resting our bodies, we allow time for(3) ________ maintenance work to be done. Any (4)________ that there is can be put right more quickly if energy isn’t being used up doing other things. Sleep is controlled by certain chemicals. These build up during the day, eventually reaching peaks that cause tiredness. We can control the effects of these chemicals to some extent. Caffeine helps to (5)________us awake while alcohol and some medicines make us sleepy. By using electrodes, scientists are able to (6)________what goes on in people’s heads while they sleep. They have (7)________ that when we first drop off everything slows down. The heart (8)________ more slowly and our breathing becomes shallow.
After about 90 minutes our eyes start to twitch and we go into what is called REM (Rapid Eye Movement) sleep, which is a (9)________that we’ve started to dream .You have dreams every night, even if you don’t remember them. There are many theories
about why we dream, none of them conclusive. A lot of people say they have to have eight hours’ sleep every night while others seem to (10)________on a lot less. One thing’s for sure – we all need some sleep. Going without it can have some very strange effects.

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:
Washington was the first city in history to be created solely for the purpose of governance. Following the Revolution, members of Congress had hotly debated the question of a permanent home for themselves and for those departments – the Treasury, the Patent Office and so on – which even the sketchiest of central governments would feel obliged to establish. In 1790, largely in order to put an end to congressional bickering, George Washington was charged with selecting a site for the newly designated federal district. Not much to anyone’s surprise but to the disappointment of many he chose a tract of land on the banks of the Potomac River, a few miles upstream from his beloved plantation Mount Vernon.
The District of Columbia was taken in part from Virginia and in part from Maryland. At the time it was laid out, its hundred square miles consisted of gently rolling hills, some under cultivation and the rest heavily wooded, with a number of creeks and much swampy land along the Potomac. There is now a section of Washington that is commonly referred to as Foggy Bottom; that section bore the same nickname a hundred and eighty years ago.
Two ports cities, Alexandria and Georgetown, flourished within sight of the new capital and gave it access by ship to the most important cities of the infant nation – Charleston, Baltimore, Philadelphia, New York, Newport, Salem and Portsmouth – and also to the far-off ports of England and the Continent.

The author implies that Georgetown was important in the eighteen century because it

Read the passage and choose the best answers:

Never say anything negative about past experiences, employers, or courses or professors. Always think of something positive about an experience and talk about that. You should also be __(1)__. If you are genuinely interested __(2)__ the job, let the interviewer know that.

One of the best ways to show you are keen on a job is to demonstrate that you have researched the organization prior to the interview. You can also __(3)__ interest by asking questions about the job, the organization, and its service and products. The best way to impress an employer is to ask questions that build your interview discussion. This shows you are interested and __(4)__ close attention to the interviewer. It is a good idea to prepare a few questions in advance, but an insightful comment based on your conversation can make an even stronger statement. At the __(5)__ of the interview, it is appropriate for you to ask when you may expect to hear from the employer.

__(4)__

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:
William Sydney Porter (1862-1910), who wrote under the pseudonym of O. Henry, was born in North Carolina. His only formal education was to attend his Aunt Lina’s school until the age of fifteen, where he developed his lifelong love of books. By 1881 he was a licensed pharmacist. However, within a year, on the recommendation of a medical colleague of his Father’s, Porter moved to La Salle County in Texas for two years herding sheep. During this time, Webster’s Unabridged Dictionary was his constant companion, and Porter gained a knowledge of ranch life that he later incorporated into many of his short stories. He then moved to Austin for three years, and during this time the first recorded use of his pseudonym appeared, allegedly derived from his habit of calling “Oh, Henry” to a family cat. In 1887, Porter married Athol Estes. He worked as a draftsman, then as a bank teller for the First National Bank.
In 1894 Porter founded his own humor weekly, the “Rolling Stone”, a venture that failed within a year, and later wrote a column for the Houston Daily Post. In the meantime, the First National Bank was examined, and the subsequent indictment of 1886 stated that Porter had embezzled funds. Porter then fled to New Orleans, and later to Honduras, leaving his wife and child in Austin. He returned in 1897 because of his wife’s continued ill-health, however she died six months later. Then, in 1898 Porter was found guilty and sentenced to five years imprisonment in Ohio. At the age of thirty five, he entered prison as a defeated man; he had lost his job, his home, his wife, and finally his freedom. He emerged from prison three years later, reborn as O. Henry, the pseudonym he now used to hide his true identity. He wrote at least twelve stories in jail, and after re-gaining his freedom, went to New York City, where he published more than 300 stories and gained fame as America’s favorite short Story writer. Porter married again in 1907, but after months of poor health, he died in New York City at the age of forty-eight in 1910. O. Henry’s stories have been translated all over the world.

The author implies which of the following is true?

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:
A term 'megalopolis' (or megacity) was first used by French geographer Jean Gottman to describe the north-eastern United States in 1961. The term is used more widely now and is defined as an urban area of more than 10 million inhabitants dominated by a low-density housing. In 1995 there were 14 megacities. By 2020 there could be 30.
Megacities are the result of the process of urbanization. After cities grew into crowded urban centres, people who could afford to move into suburbs at the edge of the city. When the suburbs in turn became crowded, people moved into villages and dormitory towns outside the city, but within commuting distance. In this way, for the first time since industrialisation, the countryside began to gain population, whereas cities lost their inhabitants. In the 1980s St Louis and Detroit in the America lost between 35 and 47 per cent of their populations and London lost 15 per cent in the 20 years to 1971.
However, this movement away from cities does not mean that the city is dying. In fact it is spreading. From the old city develops a metropolitan area with many low-level urban developments. When these metropolitan areas merge together, they form megacities which contain over 10 million people. The largest of these is in America, called Boswash - a region over 300 miles long from Boston in the north to Washington, DC in the south with more than 44 million people. There are emerging megalopolises in Britain centred around London and the south-east, in Germany in the industrial region of the Ruhr and Japan in the Tokyo-Osaka-Kyoto region.

Which is the best title for paragraph 3?

The protozoans, minute, aquatic creatures each of which consists of a single cell of protoplasm, constitute a classification of the most primitive forms of animal life. They are fantastically diverse, but three major groups may be identified on the basis of their motility. The Mastigophora have one or more long tails, which they use to project themselves forward. The Ciliata, which use the same basic means for locomotion as the Mastigophora, have a larger number of short tails. The Sarcodina, which include amoebae, float or row themselves about on their crusted bodies.
In addition to their form of movement, several other features discriminate among the three groups of protozoans. For example, at least two nuclei per cell have been identified in the Ciliata, usually a large nucleus that regulates growth but decomposes during reproduction, and a smaller one that contains the genetic code necessary to generate the large nucleus.
Protozoans are considered animals because, unlike pigmented plants to which some protozoans are otherwise almost identical, they do not live on simple organic compounds. Their cell demonstrates all of the major characteristics of the cells of higher animals.
Many species of protozoans collect into colonies, physically connected to each other and responding uniformly to outside stimulate. Current research into this phenomenon, along with investigations carried out with advanced microscopes may necessitate a redefinition of what constitutes protozoans, even calling into question the basic premise that they have only one cell. Nevertheless, with the current data available, almost 40,000 species of protozoans have been identified. No doubt, as the technology improves our methods of observation, better models of classification will be proposed.

Which of the following statements are NOT true of protozoans?

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:
The increase in international business and in foreign investment has created a need for executives with knowledge of foreign languages and skills in cross-culture communication. Americans, however, have not been well trained in either area and, consequently, have not enjoyed the same level of success in negotiation in an international arena as have their foreign counterpart.
Negotiating is the process of communicating back and forth for the purpose of reaching an agreement. It involves persuasion and compromise, but in order to participate in either one, the negotiators must understand the ways in which people are persuaded and how compromise is reached within the culture of the negotiation.
In many international business negotiations abroad, Americans are perceived as wealthy and impersonal. It often appears to the foreign negotiator that the American represents a large multimillion- dollar corporation that can afford to pay the price without bargaining further. The American negotiator’s role becomes that of an impersonal purveyor of information and cash, an image that succeeds only in undermining the negotiation.
In studies of American negotiators abroad, several traits have been indentified that may serve to confirm this stereotypical perception, while subverting the negotiator's position. Two traits in particular that cause cross-culture misunderstanding are directness and impatience on the part of American negotiator. Furthermore, American negotiators often insist on realizing short-term goals. Foreign negotiators, on the other hand, may value the relationship established between negotiators and may be willing to invest time in it for long-term benefits. In order to solidify the relationship, they may opt for indirect interactions without regard for the time involved in getting to know the other negotiator.
Clearly, perceptions and differences in values affect the outcomes of negotiations and the success of negotiators. For Americans to play a more effective role in international business negotiations, they must put forth more effort to improve cross-cultural understanding.

The American negotiator is described as all of the following EXCEPT ....................

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:
A gesture is an action that sends a message from one person to another without using words. We use gestures to communicate with others. There are some gestures that have completely different meaning depending on when and where they are used.
When an American wants to show that something is OK. or good, he raises his hand and makes a circle with his thumb and foreigners. The circle sign has only one meaning for him. He might be surprised to learn that in other countries it can mean something different. In Japan, for instance, it is the gesture for money. In France, it means 'zero' or 'worthless'. Such differences can lead to all kinds of misunderstanding when foreigners meet. But why is it that the same gesture has so many different meanings?
When some people want to show that something is exact or precise, they make a sign to show that they are holding something between the tips of their thumb and forefinger. Many people from all over the world do this when they want to make a specific point as they are speaking. People later started using this signal to mean 'exactly right' or 'perfect'. This was how the famous OK was bom.
In Japan, money means coins and coins are around. Therefore, making a round hand sign came to represent money. It is simple as that. The French sign for 'nothing' or 'worthless' also has a simple origin. This time the circle doesn't represent a coin, but nought. Nought equals zero, zero equals nothing, nothing equals worthless.

Which of the following statements is true?

It was the first photograph that I had ever seen, and it fascinated me. I can remember holding it at every angle in order to catch the flickering light from the oil lamp on the dresser. The man in the photograph was unsmiling, but his eyes were kind. I had never met him, but I felt that I knew him. One evening when I was looking at the photograph, as I always did before I went to sleep, I noticed a shadow across the man’s thin face. I moved the photograph so that the shadow lay perfectly around his hollow cheecks. How different he looked!
That night I could not sleep, thinking about the letter that I would write. First, I would tell him that I was eleven years old, and that if he had a little girl my age, she could write to me instead of him. I knew that he was a very busy man. Then I would explain to him the real purpose of my letter. I would tell him how wonderful he looked with the shadow that I had seen across his photograph, and I would most carefully suggest that he grow whiskers.
Four months later when I met him at the train station near my home in Westfield, New York, he was wearing a full beard. He was so much taller than I had imagined from my tiny photograph.
“Ladies and gentlemen,” he said, “I have no speech to make and no time to make it in. I appear before you that I may see you and that you may see me.” Then he picked me right up and kissed me on both cheeks. The whiskers scratched. “Do you think I look better, my little friend?” he asked me.
My name is Grace Bedell, and the man in the photograph was Abraham Lincoln.

From this passage, it may be inferred that...........

The Native American peoples of the north Pacific Coast created a highly complex maritime culture as they invented modes of production unique to their special environment. In addition to their sophisticated technical culture, they also attained one of the most complex social organizations of any nonagricultural people in the world.
In a division of labor similar to that of the hunting peoples in the interior and among foraging peoples throughout the world, the men did most of the fishing, and the women processed the catch. Women also specialized in the gathering of the abundant shellfish that lived closer to shore. They collected oysters, crabs, sea urchins, mussels, abalone, and clams, which they could gather while remaining close to their children. The maritime life harvested by the women not only provided food, but also supplied more of the raw materials for making tools than did fish gathered by the men. Of particular importance for the native tool than did the fish gathered by the men. Of particular made from the larger mussel shells, and a variety of cutting edges that could be made from other marine shells.
The women used their tools to process all of the fish and marine mammals brought in by the men. They cleaned the fish, and dried vast quantities of them for the winter. They sun-dried fish when practical, but in the rainy climate of the coastal area they also used smokehouses to preserve tons of fish and other seafood annually. Each product had its own peculiar characteristics that demanded a particular way of cutting or drying the meat, and each task required its own cutting blades and other utensils.
After drying the fish, the women pounded some of them into fish meal, which was an easily transported food used in soups, stews, or other dishes to provide protein and thickening in the absence of fresh fish or while on long trips. The women also made a cheese-like substance from a mixture of fish and roe by aging it in storehouses or by burying it in wooden boxes or pits lined with rocks and tree leaves.

The word “attained” is closest in meaning to ..........

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:
In the United States, friendship can be close, constant, intense, generous and real, yet fade away in a short time if circumstances change. Neither side feels hurt by this. Both may exchange Christmas greetings for a year or two, perhaps a few letters for a while - then no more. If the same two people meet again by chance, even years later, they pick up the friendship where they left off and are delighted.
In the United States, you can feel free to visit people's homes, share their holidays, or enjoy their lives without fear that they are taking on a lasting obligation. Do not hesitate to accept hospitality because you can’t give it in turn. No one will expect you to do so for they know you are far from home. Americans will enjoy welcoming you and be pleased if you accept their hospitality easily.
Once you arrived there, the welcome will be fun, warm, and real. Most visitors find themselves readily invited into many homes there. In some countries it is considered inhospitable to entertain at home, offering what is felt as only home cooked food, not doing something for your guests." It is felt that restaurant entertaining shows more respect and welcome. Or for other different reasons, such as crowded space, language difficulties, or family customs, outsiders are not invited into homes.
In the United States, both methods are used, but it is often considered friendlier to invite a person to one's home than to go to a public place, except in purely business relationship. So, if your host or hostess brings you home, do not feel that you are being shown inferior treatment.
Don't feel neglected if you do not find flowers awaiting you in your hotel room, either. Flowers are very expensive there; hotel delivery is uncertain; arrival times are delayed, changed or cancelled - so flowers are not customarily sent as a welcoming touch. Please do not feel unwanted! Outward signs vary in different lands; the inward welcome is what matters, and this will be real.

In the United States, friendship will    if circumstances change.

It's called 42 - the name taken from the answer to the meaning of life, from the science fiction series The Hitchhiker's Guide to the Galaxy. 42 was founded by French technology billionaire Xavier Niel, whose backing means there are no tuition fees and accommodation is free. Mr Niel and his co-founders come from the world of technology and start-ups, and they are trying to do to education what Facebook did to communication and Airbnb to accommodation.
Students at 42 are given a choice of projects that they might be set in a job as a software engineer - perhaps to design a website or a computer game. They complete a project using resources freely available on the Internet and by seeking help from their fellow students, who work alongside them in a large open-plan room full of computers. Another student will then be randomly assigned to mark their work.
The founders claim this method of learning makes up for shortcomings in the traditional education system, which they say encourages students to be passive recipients of knowledge. "Peer-to-peer learning develops students with the confidence to search for solutions by themselves, often in quite creative and ingenious ways."
Like in computer games, the students are asked to design and they go up a level by completing a project. They graduate when they reach level 21, which usually takes three to five years. And at the end, there is a certificate but no formal degree. Recent graduates are now working at companies including IBM, Amazon, and Tesla, as well as starting their own firms.
"The feedback we have had from employers is that our graduates are more apt to go off and find out information for themselves, rather than asking their supervisors what to do next," says Brittany Bir, chief operating officer of 42 in California and a graduate of its sister school in Paris. Ms Bir says 42's graduates will be better able to work with others and discuss and defend their ideas - an important skill in the “real world” of work. "This is particularly important in computer programming, where individuals are notorious for lacking certain human skills," she says. 
But could 42's model of teacher less learning work in mainstream universities? Brittany Bir admits 42's methods do not suit all students. "It suits individuals who are very disciplined and self-motivated, and who are not scared by having the freedom to work at their own pace," she says.

The author mentions “to design a website or a computer game” in paragraph 2 to illustrate ............

For a time, the Hubble telescope was the brunt of jokes and subject to the wrath of those who believed the U.S government had spent too much money on space projects that served no valid purpose. The Hubble was sent into orbit with a satellite by the Space Shuttle Discovery in 1990 amid huge hype and expectation. Yet after it was in position, it simply did not work. Because the primary mirror was misshapen, it was not until 1993 that the crew of the Shuttle Endeavor arrived like roadside mechanics, opened the hatch that was installed for the purpose, and replaced the defective mirror with a good one.

Suddenly, all that had originally been expected came true. The Hubble telescope was indeed the “window on the universe”, as it had originally been dubbed. When you look deep into space, you are actually looking back through time, because even though light travels at 186,000 miles a second, it requires time to get from one place to another. In fact, it is said that in some cases, the Hubble telescope is looking back eleven billion years to see galaxies already forming. The distant galaxies are speeding away from Earth, some travelling at the speed of light.

Hubble has viewed exploding stars such as the Eta Carinae, which clearly displayed clouds of gas and dust billowing outward from its poles at 1.5 million miles an hour. Prior to Hubble, it was visible from traditional telescopes on Earth, but its details were not as certainable. But now, the evidence of the explosion is obvious. The star still burns five million times brighter than the Sun and illuminates clouds from the inside.

Hubble has also provided a close look at black holes, which are described as comic drains. Gas and dust swirl around the drain and are slowly sucked in by the incredible gravity. It has also looked into an area that looked empty to the naked eye and, within a region the size of a grain of sand, located layer upon layer of galaxies, with each galaxy consisting of billions of stars.

The Hubble telescope was named after Edwin Hubble, a 1920s astronomer who developed a formula that expresses the proportional relationship of distances between clusters of galaxies and the speeds at which they travel. Astronomers use stars known as Cepheid variables to measure distances in space. These stars dim and brighten from time to time, and they are photographed over time and charted. All the discoveries made by Hubble have allowed astronomers to learn more about the formation of early galaxies.

The author states that the Hubble was not always popular because ............

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:
In young language learners, there is a critical period of time beyond which it becomes increasingly difficult to acquire a language. Children generally attain proficiency in their first language by the age of five and continue in a state of relative linguistic plasticity until puberty. [A] Neurolinguistic research has singled out the lateralization of the brain as the reason for this dramatic change from fluidity to rigidity in language function. Lateralization is the process by which the brain hemispheres become dominant for different tasks. The right hemisphere of the brain controls emotions and social functions, whereas the left hemisphere regulates the control of analytical functions, intelligence, and logic. [B] For the majority of adults, language functions are dominant on the left side of the brain. [C] Numerous studies have demonstrated that it is nearly impossible to attain a nativelike accent in a second language, though some adults have overcome the odds, after lateralization is complete. [D]
Cognitive development also affects language acquisition, but in this case adult learners may have some advantages over child learners. Small children tend to have a very concrete, here- and-now view of the world around them, but at puberty, about the time that lateralization is complete, people become capable of abstract thinking, which is particularly useful for language. Generally speaking, adults can profit from grammatical explanations, whereas children cannot. This is evidenced by the fact that children are rather unreceptive to correction of grammatical features and instead tend to focus on the meaning of  an utterance rather than its form. However, language learning theory suggests that for both adults and children, optimal language acquisition occurs in a meaning centered context. Though children have the edge over adult language learners with respect to attaining a nativelike pronunciation, adults clearly have an intellectual advantage which greatly facilitates language learning.

The word “critical” could best be replaced by     .

No educational medium better as means of spatial communication than the atlas. Atlases deal with such invaluable information as population distribution and density. One of the best, Pennycooke's World Atlas, has been widely accepted as a standard owing to the quality of its maps and photographs, which not only show various settlements but also portray them in a variety of scales. In fact, the very first map in the atlas is a cleverly designed population cartogram that projects the size of each country if geographical size were proportional to population. Following the proportional layout, a sequence of smaller maps shows the world’s population density, each country’s birth and death rates, population increase or decrease, industrialization, urbanization, gross national product in terms of per capita income, the quality of medical care, literacy, and language. To give readers a perspective on how their own country fits in with the global view, additional projections depict the world's patterns in nutrition, calorie and protein consumption, health care, number of physicians per unit of population, and life expectancy by region. Population density maps on a subcontinental scale, as well as political maps. Convey the diverse demographic phenomena of the world in a broad array of scales.

In the passage, the word “invaluable” is closet in meaning to ...........

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:
What unusual or unique biological train led to the remarkable diversification and unchallenged success of the ants for over 50 million years? The answer appears to be that they were the first group of predatory eusocial insects that both lived and foraged primarily in the soil and in rotting vegetation on the ground. Eusocial refers to a form of insect society characterized by specialization of tasks and cooperative care of the young; it is rare among insects. Richly organized colonies of the land made possible by eusociality enjoy several key advantages over solitary individuals.
Under most circumstances groups of workers are better able to forage for food and defend the nest, because they can switch from individual to group response and back again swiftly and according to need. When a food object or nest intruder is too large for one individual to handle, nestmates can be quickly assembled by alarm or recruitment signals. Equally important is the fact that the execution of multiple- step tasks is accomplished in a series-parallel sequence. That is, individual ants can specialize in particular steps, moving from one object (such as a larva to be fed) to another (a second larva to be fed). They do not need to carry each task to completion from start to finish - for example, to check the larva first, then collect the food, then feed the larva. Hence, if each link in the chain has many workers in attendance, a sense directed at any particular object is less likely to fail. Moreover, ants specializing in particular labor categories typically constitute a caste specialized by age or body form or both. There has been some documentation of the superiority in performance and net energetic yield of various castes for their modal tasks, although careful experimental studies are still relatively few.

What makes ants unusual in the company of eusocial insects is the fact that they are the only eusocial predators (predators are animals that capture and feed on other animals) occupying the soil and ground litter. The eusocial termites live in the same places as ants and also have wingless workers, but they feed almost exclusively on dead vegetation.

The task of feeding larvae is mentioned in the passage to demonstrate     .

It was the first photograph that I had ever seen, and it fascinated me. I can remember holding it at every angle in order to catch the flickering light from the oil lamp on the dresser. The man in the photograph was unsmiling, but his eyes were kind. I had never met him, but I felt that I knew him. One evening when I was looking at the photograph, as I always did before I went to sleep, I noticed a shadow across the man’s thin face. I moved the photograph so that the shadow lay perfectly around his hollow cheecks. How different he looked!
That night I could not sleep, thinking about the letter that I would write. First, I would tell him that I was eleven years old, and that if he had a little girl my age, she could write to me instead of him. I knew that he was a very busy man. Then I would explain to him the real purpose of my letter. I would tell him how wonderful he looked with the shadow that I had seen across his photograph, and I would most carefully suggest that he grow whiskers.
Four months later when I met him at the train station near my home in Westfield, New York, he was wearing a full beard. He was so much taller than I had imagined from my tiny photograph.
“Ladies and gentlemen,” he said, “I have no speech to make and no time to make it in. I appear before you that I may see you and that you may see me.” Then he picked me right up and kissed me on both cheeks. The whiskers scratched. “Do you think I look better, my little friend?” he asked me.
My name is Grace Bedell, and the man in the photograph was Abraham Lincoln.

What is the author’s main purpose in the passage?