Passage Five

Modern humans emerged some 250,000 years ago, yet agriculture is a fairly recent invention, only about 10,000 years old. Many crop plants are rather new additions to our diet: broccoli (a flowering mutant of kale) is thought to be only 500 years old. Most innovation is far more recent still. Although Austrian monk Gregor Mendel's pea plant experiments quietly laid the basic foundations of genetics in the mid-19th century, his work was rediscovered and applied to crop breeding only at the beginning of the 20th century.

Further advances have steadily accumulated. The 1940s saw the identification of DNA as genetic material and the adoption, by commercial breeders, of genetic modification - typically by applying chemicals or radiation to DNA to try to make plants with advantageous characteristics. The modifications ultimately led to the green revolution of the 1960s and 1970s, during which time global wheat yields tripled. The 1980s and 1990s saw the commercial adoption of agricultural biotechnology, which has allowed breeders to introduce specific genes into crops from the same or different species. In 2004 the first plant genome was fully sequenced, and since then the number of plant gene sequences in GenBank, the public repository for gene sequence information, has been doubling every two years. Our knowledge is increasing exponentially, as it has been in other fields such as semiconductors and cellular telephony.

Our challenge is to increase agricultural yields while decreasing the use of fertilizer, water, fossil fuels and other negative environmental inputs. Embracing human ingenuity and innovation seems the most likely path. Plants did not evolve to serve humans, and their sets of genes are incomplete for our purposes. The integral role of modifying genes is obvious to all breeders, though sometimes painfully absent from the public's understanding of how modern agriculture succeeds. All breeding techniques, from before Mendel's time until today, exploit modifications to plant DNA. These modifications can take the form of mistakes or mutations that occur during natural cell division in the wild; the natural but random movement of DNA sequences from one part of a plant's genome to another; or the more precise insertion of known gene sequences using biotechnology. In all these cases, plant genes are moved within or across species, creating [novel] combinations. Hybrid genetics - the combination of different versions of the same gene – has resulted in spectacular yield increases. Largely as the consequence of using hybrid seed varieties, corn yields in the U.S. have increased more than 500 percent in the past 70 years.

Questions 21-25 are based on Passage Five.

Which statement is correct according to paragraph one?

Paragraph Ten

Some experts estimate that youngsters are bombarded with 10,000 food commercials each year during children's programming, and most of them aren’t promoting salads or fruit. All this marketing changes children’s taste preferences and causes them to crave - and beg for - unhealthy foods. 

Food commercials are largely r      for children's unhealthy eating habits.

Let’s take the orthodox definition of the word bargain. It is something offered at a low and advantageous price. It is an opportunity to buy something at a lower price than it is really worth. (46. A more recent definition is: a bargain is a dirty trick to extort money from the pockets of silly and innocent people.)

I have never attended a large company's board meeting in my life, but I feel certain that discussion often takes the following lines. The cost of producing a new - for example - toothpaste would make 80p the decent price for it, so we will market it at ￡1.20. (47. It is not a bad toothpaste (not specially good either, but not bad), and as people like to try new things it will sell well to start with; but the attraction of novelty soon fades, so sales will fall. When that starts to happen we will reduce the price to ￡1.15.) And we will rush to buy it even though it still costs forty-three percent more than its fair price.

Sometimes it is not 5p OFF but 1p OFF. What breathtaking impertinence to advertise 1p OFF your soap or washing powder or dog food or whatever. Even the poorest old-age pensioner ought to regard this as an insult, but he doesn’t. A bargain must not be missed. (48. To be offered a “gift” of one penny is like being invited to dinner and offered one single pea (tastily cooked), and nothing else.) Even if it represented a real reduction it would be an insult. Still, people say, one has to have washing powder (or whatever) and one might as well buy it a penny cheaper.

The real danger starts when utterly unnecessary things become “bargains”. There is a huge number who just cannot resist bargains and sales. Provided they think they are getting a bargain they will buy clothes they will never wear, furniture they have no space for. Old ladies will buy roller-skates and nonsmokers will buy pipe-cleaners.

(49. Quite a few people actually believe that they make money on such bargains. Some people buy in bulk because it is cheaper.) At certain moments New Zealand lamb chops may be 3p cheaper if you buy half a ton of them, so people rush to buy a freezer just to find out later that it is too small to hold half a tone of New Zealand lamb.

To offer bargains is a commercial trick to make the poor poorer. When greedy fools fall for this trick, it serves them right. (50. All the same, if bargains were prohibited by law our standard of living would immediately rise by 7.39 percent.)

Paragraph Nine

The benefits of quitting smoking - reduced risk of cancer and many other health problems - are known. But for millions of smokers, the calming effect of a cigarette can be reason enough to start up again. Studies have found, however, that in reality, lighting up has the opposite effect, causing long-term stress levels to rise, not fall.

Smoking may well cause rather than r      stress.

Paragraph Seven

Today roughly 17% of American kids and teens are obese, and parents cite obesity as a top concern for their children's health. Yet with so many other overweight kids in the class, it appears that parents can't recognize - or admit it to themselves - when their child is too heavy.

Parents may f      to realize it when their children are overweight.

Paragraph Eight

In the 1990s, the Environmental Protection Agency shut down thousands of leaky landfills, building larger ones with stricter environmental controls. Which means that if you do live near one, it's likely to be a whopper: There were 8,000 landfills in the United States in 1988, and there are fewer than 2,000 today.

The n      of landfills has decreased.

Paragraph Five

Well-intentioned parents have unwittingly left their kids defenseless against failure. The current generation of millennials (born between 1980 and 2001) grew up playing sports where scores and performance were downplayed because “everyone’s a winner”. And their report cards had more positive spin than an AIG press release.

Today's children have been poorly p      for failure.

Paragraph Six

The harp seal mom nurses her pup on 48% fat seal milk continuously for 12 days without eating. Her pup will gain an average of 2.3 kg per day during this 12-day nursing period, while mom herself will lose about 3.2 kg per day.

The harp seal mom's significant w      loss during nursing.

Paragraph Four

In the movie, the principal character, Leonard, can remember everything that happened before his head injury on the night his wife was attacked, but anyone he meets or anything he has done since that fateful night simply vanishes. He has lost the ability to convert short-term memory into long-term memory.

Leonard’s head injury has r      in his loss of long-term memory.

Paragraph One

Desertification, drought, and despair - that's what global warming has in store for much of Africa. Or so we hear. Emerging evidence is painting a very different scenario, one in which rising temperatures could benefit millions of Africans in the driest parts of the continent. The Sahara desert and surrounding regions are greening due to increasing rainfall.

Sahara desert turns g    thanks to more rain.

Paragraph Three

Daylight saving time began in the United States during World War I, primarily to save fuel by reducing the need to use artificial lighting. Although some states and communities observed daylight saving time between the wars, it was not observed nationally again until World War Ⅱ.

Daylight saving time in the U. S. reduced e      consumption.