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Living things include both the visible world of animals, plants, and fungi as well as the invisible world of bacteria and viruses. On a basic level, we can say that life is ordered. Organisms have an enormously complex organization. We're all familiar with the intricate systems of the basic unit of life, the cell. Life can also "work." Living creatures can take in energy from the environment. This energy, in the form of food, is transformed to maintain metabolic processes and for survival. Life grows and develops. This means more than just replicating or getting larger in size. Living organisms also have the ability to rebuild and repair themselves when injured. Life can reproduce. Think about the last time you accidentally stubbed your toe. Almost instantly, you moved back in pain. Finally, life can adapt and respond to the demands placed on it by the environment. There are three basic types of adaptations that can occur in higher organisms.
Reversible changes occur as a response to changes in the environment. Let's say you live near sea level and you travel to a mountainous area. You may begin to experience difficulty breathing and an increase in heart rate as a result of the change in altitude. These symptoms go away when you go back down to sea level. Body-related changes occur as a result of prolonged changes in the environment. Using there previous example, if you were to stay in the mountainous area for a long time, you would notice that your heart rate would begin to slow down and you would begin to breath normally. These changes are also reversible. Genotypic changes (caused by genetic mutation) take place within the genetic makeup of the organism and are not reversible. An example would be the development of resistance to pesticides by insects and spiders.

Which of the following is NOT a feature of life?

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In the late 1960’s, many people in North America turned their attention to environmental problems and new steel-and-glass skyscrapers were widely criticized. Ecologists pointed out that a cluster of tall buildings in a city often overburdens public transportation and parking lot capacities.
Skyscrapers are also lavish consumers, and waster, of electric power. In one recent year, the addition of 17 million square feet of skyscraper office space in New York City raised the peak daily demand for electricity by 120,-000 kilowatts- enough to supply the entire city of Albany, New York, for a day.
Glass-walled skyscrapers can be especially wasteful. The heat loss (or gain) through a wall of half-inch plate glass is more than ten times that through a typical masonry wall filled with insulation board. To lessen the strain on heating and air- conditioning equipment, builders of skyscrapers have begun to use double glazed panels of glass, and reflective glasses coated with silver or gold mirror films that reduce glare as well as heat gain. However, mirror-walled skyscrapers raise the temperature of the surrounding air and affect neighboring buildings.
Skyscrapers put a severe strain on a city’s sanitation facilities, too. If fully occupied, the two World Trade Center towers in New York City would alone generate 2.25 million gallons of raw sewage each year-as much as a city the size of Stamford, Connecticut, which has a population of more than 109,000.
Skyscrapers also interfere with television reception, block bird flyways, and obstruct air traffic. In Boston, in the late 1960’s some people even feared that shadows from skyscrapers would kill the grass on Boston Common.
Still, people continue to build skyscrapers for all the reasons that they have always built them – personal ambition, civic pride, and the desire of owners to have the largest possible amount of rentable space.

According to the passage, all of the following are mentioned as reasons for building skyscrapers EXCEPT

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Welcome to the Netherlands, a tiny country that only extends, at its broadest, 312 km north to  south, and 264 km east to west - (1) ......... the land area increases slightly each year as a result of continuous land reclamation and drainage. With a lot of heart and much to offer, ‘Holland,’ as it is (2).......known to most of us abroad - a name stemming from its once most prominent provinces - has more  going  on  per  kilometer  than  most  countries,  and  more  English-speaking  natives.  You’ll  be impressed by its (3).....cities and charmed by its countryside and villages, full of contrasts. From the exciting variety on offer, you could choose a romantic canal boat tour in Amsterdam, a Royal Tour by coach in The Hague, or a hydrofoil tour around the biggest harbour in the world - Rotterdam. In season you could visit the dazzling bulb fields, enjoy a full day on a boat, or take a bike tour through the pancake-flat countryside spiced with windmills. The possibilities are countless and the nationwide tourist office is on hand to give you information and help you (4)...... reservations.  You’ll  have (5)........language problems here, as the Dutch are true linguists and English is spoken here almost universally.
(5)...........................

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You might be surprised to know that bicycles have existed for less than two hundred years. Though the earliest comes from a sketch said to be from 1534 and attributed to Gian Giacomo, there are several early but unverified claims for the invention of the modem bicycle. No one is sure who invented this popular two- wheeled machine, but it was probably either the German Karl von Drais, in 1817, or the American W K Clarkson, in 1819. The early models didn't look much like the bicycles of today. The front wheel was much bigger than the back one, and also there weren't any pedals - riders had to move themselves forward by pushing their feet against the ground. Pedals finally arrived in the 1840s, and in 1879 an Englishman named Henry Lawson had the idea of connecting them to the back wheel with a chain. Gears, which made things much easier for those cycling uphill, first appeared in the 1890s.
There are now approximately one billion bicycles in the world - more than twice the total number of cars - and they are the main form of transport in some developing countries. They have to compete with cars on the streets of all the world’s cities, and the two forms of transport don't always mix well. In London in 2005, for example, over 300 cyclists were either killed or seriously injured in accidents involving cars. Even though bicycles are much more environmentally friendly than cars, most governments don't do much to encourage people to ride rather than drive. In China, which is famous for having a huge number of bicycles (about 200 million), the authorities in the city of Shanghai even banned cycling for a while in 2003.
Cycling is on the rise is the United Kingdom, and the number of annual journeys made by bike in London has increased 50% over the last five years. Experts say there is a mixture of reasons for this boom: concerns about the environment, the desire to keep fit, and also the fact that cycling is often not only cheaper but also quicker than travelling by car.
However, although one in three British adults owns a bicycle, they still don't use them nearly as much as they could. Bikes are used for a mere 2% of journeys in the UK, while the figure for the Netherlands is an impressive 27%.
Cycling is becoming more popular as a competitive sport, and the most famous race is of course the three-week Tour de France, which takes place every July. American Lance Armstrong won it every year from 1999 to 2005 - one of the greatest individual sporting achievements of all time.

Why didn't early bicycles look much like today's models?

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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 “unreceptive” is closest in meaning to     .

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Scientists have experimented with a new procedure for alleviating the damage caused by strokes. Strokes are frequently caused by a blood clot lodging in the tree of arteries in the head, choking the flow of blood. Some brain cells die as a direct result of the stroke, but others also die over several hours because the proteins spilling out of the first cells that die trigger a chemical chain reaction that kills the neighboring cells.
The current method of reducing the amount of damage is to give a clot dissolver, known as TPA, as soon as possible. But generally TPA is not given to the patient until he or she reaches the hospital, and it still does not immediately stop the damage.
The new technology, still in the research stage, involves chilling the area or the entire patient. It is already known that when an organ is cooled, damage is slowed. This is why sometimes a person who has fallen into an icy pond is not significantly harmed after being warmed up again. The biggest issue is the method of cooling. It is not feasible to chill the head alone. Doctors have chilled the entire body by wrapping the patient in cold materials, but extreme shivering was a problem.
The new idea is to cool the patient from the inside out. Several companies are studying the use of cold-tipped catheters, inserted into the artery in the groin and threaded up to the inferior vena cava, which is a large vein that supplies blood to the abdomen. The catheter is expected to cool the blood that flows over it, thus allowing cooler blood to reach the area of the stroke damage.
It is not expected that the cooling will be substantial, but even a slight decrease in temperature is thought to be helpful. In effect, the patient is given a kind of forced hypothermia. And doctors believe it is important to keep the patient awake so that they can converse with the patient in order to ascertain mental condition.
Studies continue to determine the most effective and least damaging means of cooling the patient in order to reduce this damage.

According to the passage, what causes a stroke?

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."

2. it has developed a more (2)…. economy and has become an important financial, trade, and transportation center. 

Read the following passage and choose the best answer for each blank.

Vietnam is considered a third world country, its people live (26) _____ poverty by the millions. After the (27) _____, Vietnam's economy remained dominated by small-scale production, low labor productivity, (28) _____, material and technological shortfalls, and insufficient food and (29) _____ goods. The Doi Moi reforms that were instated in 1986 have shed new light and added new features to the Vietnamese economy. (30) ____ Vietnamese Communist Party plays a leading role in establishing the foundations and principles of communism, mapping strategies for economic development, setting growth targets, and (31) _____ reforms. Doi Moi combined government planning with free-market incentives and (32) _____ the establishment of private businesses and foreign investment, including foreign-owned enterprises. By the late 1990s, the success of the business and agricultural reforms ushered in under Doi Moi was evident. (33) _____ than 30,000 private businesses had been created, and the economy was growing at an annual (34) _____ of more than 7 percent. Farming systems research and the international development projects are a source of new hope for the people of Vietnam. If these recent projects are successful and Doi Moi continues on its current path the Vietnamese people may (35) _____ a new standard of living. More reforms like Doi Moi need to take place in order to create a more stable Vietnamese future.

(30) _____

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“They told me I could never walk again. But when I listened to music, I forgot all about the pain. I found the strength I didn’t know I had.”Ninety-two-year-old Tina Goodman, who regained her ability to walk, thanks to music.
This is just one of the many stories in Fettaro’s book “The Healing Power of Music” . Fettaro tries to show just how important music is in our lives and how it can help us to be healthy and happy.
According to Fettaro, music can make sick people again. In fact, his book comes with a CD of recordings, each one specially designed to help with a number of health problems.
Fettaro, e well-known music therapist, promises that by reading his book, you will be able to develop the healing power of music in your life. He says this will help you fight headaches and back pain, as well as reduce stress, high blood pressure, and many other common illnesses.
Certainly, I accept that listening to certain types of music can help with particular problems, such as stress. I am also comfortable with Fettaro’s claim that by reading his book, you’ll be able to create a peaceful enviroment to help you relax in your home. I found the relaxation and breathing techniques very useful. Similarly his claim that music help you sleep better seems reasonable. Yet when he goes on to promise his music therapies will help cure depression and even cancer, he begins to sound a little bit unbelievable.
Nevertheless, for those of you who are interested in the power of music to heal, this is a great book to buy. It’s a thorough introduction to the history and practice of music therapy. Fettaro writes in a simple, easy to understand way and shows clearly how music can affect us positively. His basic message-that music can improve our lives-is well-presented and clear. It may even be true that certain techniques covered here can help some people recover from unpleasant health problems. However, his promises of “amazing results” seem impossible to justify.

Which word is similar to the word “justify”?

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Public holidays in the United Kingdom, commonly referred to as bank holidays, are days where most businesses and non – essential services are closed although an increasing number of retail businesses (especially the larger ones) do open on some of the public holidays. There are restrictions on trading on Sundays and Christmas Day. Four public holidays are common to all countries of the United Kingdom. These are: New Year's Day, the first Monday in May, Christmas Day, and Boxing Day. Some banks open on some bank holidays. In Scotland, while New Year's Day and Christmas Day are national holidays, other bank holidays are not necessarily public holidays, since the Scots instead observe traditional local customs and practice for their public holidays. In Northern Ireland, once again, bank holidays other than New Year's
Day and Christmas Day are not necessarily public holidays. Good Friday and Christmas Day are common law holidays, except in Scotland, where they are bank holidays. In Scotland the holiday on 1 January (or 2 January if 1 January is Sunday) is statutory, and 25 December is also a statutory holiday (or 26 December if Christmas Day falls on a Sunday). Boxing Day is a holiday traditionally celebrated  the day following Christmas Day, when servants and tradesmen would receive gifts, known as a "Christmas box", from their bosses or employers. Today, Boxing Day is the bank holiday that generally takes place on 26 December. And 28 December only is given if Boxing Day is Saturday.
Like Denmark, the United Kingdom has no national day holiday marked or celebrated for its formal founding date. Increasingly, there are calls for public holidays on the patron saints' days in England, Scotland and Wales. An online petition sent to the Prime Minister received 11,000 signatures for a public holiday in Wales on St. David's Day; the Scottish Parliament has passed a bill creating a public holiday  on St. Andrew's Day although it must be taken in place of another public holiday; campaigners in England are calling for a bank holiday on St. George's Day; and in Cornwall, there are calls for a public holiday on St. Piran's Day.

Bank holidays besides New Year's Day and Christmas Day are not public holidays in Scotland because    .

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   Before the mid-nineteenth century, people in the United States ate most foods only in season. Drying, smoking and salting could preserve meat for a short time, but the availability of fresh meat, like that of fresh milk, was very limited; there was no way to prevent spoilage. But in 1810, a French inventor named Nicolas Appert developed the cooking-and-sealing process of canning. And in the 1850’s an American named Gail Borden developed a means of condensing and preserving milk. Canned goods and condensed milk became more common during the 1860’s, but supplies remained low because cans had to be made by hand. By 1880, however, inventors had fashioned stamping and soldering machines that massproduced cans from tinplate. Suddenly all kinds of food could be preserved and bought at all times of the year.

   Other trends and inventions had also helped make it possible for Americans to vary their daily diets. Growing urban population created demand that encouraged fruit and vegetable farmers to raise more produce. Railroad refrigerator cars enabled growers and meat packers to ship perishables great distances and to preserve them for longer periods. Thus, by the 1890’s, northern city dwellers could enjoy southern and western strawberries, grapes, and tomatoes, previously available for a month at most, for up to six months of the year. In addition, increased use of iceboxes enabled families to store perishables. As easy means of producing ice commercially had been invented in the 1870’s, and by 1900 the nation had more than two thousand commercial ice plants, most of which made home deliveries. The icebox became afixture in most homes and remained so until the mechanized refrigerator replaced it in the 1920’s and 1930’s.

   Almost everyone now had a more diversified diet. Some people continued to eat mainly foods that were heavily in starches or carbohydrates, and not everyone could afford meat. Nevertheless, many families could take advantage of previously unavailable fruits, vegetables, and dairy products to achieve more varied fare.

The author implies that in the 1920’s and 1930’s home deliveries of ice _________ .

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The ocean bottom - a region nearly 2.5 times greater than the total land area of Earth - is a vast frontier that even today is largely unexplored and uncharted. Until about a century ago, the deep-ocean floor was completely inaccessible, hidden beneath waters averaging over 3,600 meters deep. Totally without light and subjected to intense pressures hundreds of times greater than at the Earth's surface, the deep-ocean bottom is a hostile environment to humans, in some ways as forbidding and remote as the void of outer space.
Although researchers have taken samples of deep-ocean rocks and sediments for over a century, the first detailed global investigation of the ocean bottom did not actually start until 1968, with the beginning ofthe National Science Foundation's Deep Sea Drilling Project (DSDP). Using techniques first developed for the offshore oil and gas industry, the DSDP's drill ship, the Glomar Challenger, was able to maintain a steady position on the ocean's surface and drill in very deep waters, extracting samples of sediments and rock from the ocean floor.
The Glomar Challenger completed 96 voyages in a 15-year research program that ended in November 1983. During this time, the vessel logged 600,000 kilometers and took almost 20,000 core samples of seabed sediments and rocks at 624 drilling sites around the world. The Glomar Challenger's core samples have allowed geologists to reconstruct what the planet looked like hundreds of millions of years ago and to calculate what it will probably look like millions of years in the future. Today, largely on the strength of evidence gathered during the Glomar Challenger's voyages, nearly all earth scientists agree on the theories of plate tectonics and continental drift that explain many of the geological processes that shape the Earth.
The cores of sediment drilled by the Glomar Challenger have also yielded information critical to understanding the world's past climates. Deep-ocean sediments provide a climatic record stretching back hundreds of millions of years, because they are largely isolated from the mechanical erosion and the intense chemical and biological activity that rapidly destroy much land-based evidence of past climates. This record has already provided insights into the patterns and causes of past climatic change - information that may be used to predict future climates.

How long did the Glomar Challenger conduct its research?

Interest is the sum charged for borrowing money for a fixed period of time. Principal is the term used for the money that is borrowed, and the rate of interest is the percent per year of the principal charged for its use. Most of the profits for a bank are derived from the interest that they charge for the use of their own or their depositor’s money.
All problems in interest may be solved by using one general equation that may be stated as follows:
Interest = Principal X Rate X Time
Any one of the four quantities – that is, interest, principal, rate, or time – may be found when the other three are known. The time is expressed in years. The rate is expressed as a decimal fraction. Thus, 6 percent interest means six cents charged for the use of $1 of principal borrowed for one year. Although the time may be less than, equal to, or greater than one year, most applications for loans are for periods of less than one year. For purpose of computing interest for short periods, the commercial year or 360 days is commonly used, but when large sums of money are involved, exact interest is computed on the basis of 365 days.

The word “fixed” in paragraph 1 is closest in meaning to..........

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.

The word “uniformly” in paragraph 4 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 word or phrase that best fits each of the numbered blanks
Choosing clothes can be difficult. Some people want to be fashionable, but they don’t want to look exactly like everybody else. Not all clothes are (1)........ for work or school, perhaps because they are not formal enough, or simply not comfortable. It is easy to buy the (2).......... size, and find that your trousers are too tight, especially if you are a little bit overweight. Very (3)........clothes make you feel slim, but when they have shrunk in the washing machine, then you have the same problem! If you buy light cotton clothes, then they might not be (4)........ enough for winter. If your shoes are not waterproof and if you aren’t (5)....... for the cold, you might look good, but feel terrible!
(1).................................

Choose the word which is stresses differently from the rest: efficient, communist, impatient, delicious

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

We won't have robot doctors for a long time, (1) ____ the human doctors we have now are beginning to learn on specialized artificial intelligence to help save time.

Google Deep Mind has just announced a partnership with University College London Hospital(UCLH) which will explore (2) ____ artificial intelligence to treat patients with head and neck cancers. The goal is to develop tools to automatically identify cancerous cells for radiology machines.

Currently, radiologists employ a manual process, called image (3) ____, to make CT and MRI scans and use them to create a map of the patient's anatomy with clear guidelines of where to direct the (4) ____.

Avoiding healthy areas of the head and neck requires that map to be extraordinarily detailed; typically it takes four hours to create. Google believes it can do the same job or better in one hour.

Deep Mind, Google's research arm, works primarily in deep learning, a form of artificial intelligence that learns to identify patterns from looking at large amount of data. In this case, DeepMind researchers will (5) ____ access to anonymized radiology scans from up to 700 former UCLH patients, and then feed them into (6) ____ that would process the scans to learn the visual difference between healthy and cancerous tissue.

The partnership will (7) ____ researchers to train their algorithms with highly-specialized, high- quality data, which theoretically will enable the algorithm to (8) ____ at a higher rate of success than if they had been using publicly available scans.

For those concerned about machines making health (9) ____ decisions, UCLH made it clear in a statement to the newspaper Guardian that clinicians will be in complete control of diagnoses and treatment.

DeepMind isn't the first care. Samsung Medison, the South Korean (10) ____ company's medical device arm, recently released an ultrasound machine that uses deep learning to quickly recommend whether breast tissue is cancerous or benign. The machine's algorithm was trained on 9,000 breast tissue scans, and is pending FDA approval in the US.

(5) ____

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Vitamins, taken in tiny doses, are a major group of organic compounds that regulate the mechanisms by which the body converts food into energy. They should not be confused with minerals, which are inorganic in their makeup. Although in general the naming of vitamins followed the alphabetical order of their identification, the nomenclature of individual substances may appear to be somewhat random and disorganized. Among the 13 vitamins known today, five are produced in the body. Because the body produces sufficient quantities of some but not all vitamins, they must be supplemented in the daily diet. Although each vitamin has its specific designation and cannot be replaced by another compound, a lack of one vitamin can interfere with the processing of another. When a lack of even one vitamin in a diet is continual, a vitamin deficiency may result.
The best way for an individual to ensure a necessary supply of vitamins is to maintain a balanced diet that includes a variety of foods and provides adequate quantities of all the compounds. Some people take vitamin supplements, predominantly in the form of tablets. The vitamins in such supplements are equivalent to those in food, but an adult who maintains a balanced diet does not need a daily supplement. The ingestion of supplements is recommended only to correct an existing deficiency due to unbalanced diet, to provide vitamins known to be lacking in a restricted diet, or to act as a therapeutic measure in medical treatment. Specifically, caution must be exercised with fat-soluble substances, such as vitamins A and D, because, taken in gigantic doses, they may present a serious health hazard over a period of time.

The author implies that foods

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.

Where do protozoans probably live?

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Cyclones in India, hurricanes in the Caribbean - severe weather events make news headlines almost weekly. Yet even in Britain, which has comparatively few climate extremes, the country is still governed by weather. If it’s pouring with rain the British might stay indoors or go to the cinema; if it’s fine they’ll have a picnic.
Most people nervously study the weather forecast the evening before if they’ve got an important appointment the following day. Even if they have nothing planned, the weather often affects their mood.
For individuals, the worst that can usually happen if the weather catches them on the hop is that they get wet. For business, the effects are far more serious. Airlines and shipping companies need to avoid severe weather and storm-force conditions. Power companies need to make sure they can supply the demand for electricity in cold weather; farmers plan their harvests around the forecast and food manufacturers increase their production of salads and other summer foods when fine weather is promised.
So who or what do meteorologists - weather forecasters as they are more commonly known - rely on when it comes to producing a forecast? Ninety percent of the information comes from weather satellites, the first of which was launched into space nearly forty years ago and was a minor revolution in the science of forecasting. Up until then, forecasters had relied on human observers to provide details of developing weather systems. As a result, many parts of the world where there were few humans around, especially the oceans, were information-free weather areas. Today, however, satellites can watch weather patterns developing everywhere.
In the UK meteorologists have also relied on releasing four weather balloons a day from eight fixed sites. These balloons measure wind, temperature and humidity as they rise upwards to a height of about 26,000 metres.
Some commercial aircraft can also be fitted with a range of forecasting instruments although this  system has certain disadvantages. For example, it can provide a great deal of information about the weather on popular routes, such as London to New York, but little about the weather on more out-of-the way routes.
Instruments aboard ships can also supply basic weather information as well as important data on wave height. Generally, the range of these instruments is fairly limited but they can indicate which direction rain is coming from, how low the cloud is and give an idea of when the weather system will reach land.
One forecaster who has made a name for himself is a man called Piers Corbyn, who bases his forecasts on watching the Sun. Most forecasters will offer forecasts for only 10 days ahead, but Corbyn’s forecasts are for 11 months. Although most meteorologists believe that there is no scientific basis for his work, Corbyn’s forecasts are used by insurance companies who want to plan months in advance.

What does ‘it’ in paragraph 6 refer to?

Before the 1500’s, the Western plains of North America were dominated by farmers. One group, the Mandans, lived in the upper Missouri River country, primarily in present-day North Dakota. They had large villages of houses built close together. The tight arrangement enabled the Mandans to protect themselves more easily from the attacks of others who might seek to obtain some of the food these highly capable farmers stored from one year to the next.
The women had primary responsibility for the fields. They had to exercise considerable skill to produce the desired results, for their northern location meant fleeting growing seasons. Winter often lingered; autumn could be ushered in by severe frost. During the spring and summer, drought, heat, hail, grasshoppers, and other frustrations might await the wary grower.
Under such conditions, Mandan women had to grow maize capable of weathering adversity. They began as early as it appeared feasible to do so in the spring, clearing the land, using fire to clear stubble from the fields and then planting. From this point until the first green corn could be harvested, the crop required labor and vigilance. Harvesting proceeded in two stages. In August the Mandans picked a smaller amount of the crop before it had matured fully. This green corn was boiled, dried, and shelled, with some of the maize slated for immediate consumption and the rest stored in animal-skin bags. Later in the fall, the people picked the rest of the corn. They saved the best of the harvest for seeds or for trade, with the remainder eaten right away or stored for later use in underground reserves. With appropriate banking of the extra food, the Mandans protected themselves against the disaster of crop failure and accompanying hunger.
The women planted another staple, squash, about the first of June, and harvested it near the time of the green corn harvest. After they picked it, they sliced it, dried it, and strung the slices before they stored them. Once again, they saved the seed from the best of the year`s crop. The Mandans also grew sunflowers and tobacco; the latter was the particular task of the older men.

Why does the author believe that the Mandans were skilled farmers?