IELTS Academic Reading Test 6 with Answers

You should spend about 20 minutes on Questions 1–13.

The salamander that never grows up

Most amphibians begin life in water and leave it as adults. A tadpole loses its tail and gills, grows legs, and climbs out onto land as a frog. The axolotl does no such thing. This small salamander, native to a handful of lakes and canals near Mexico City, spends its entire life in the water, keeping the feathery external gills and finned tail of a juvenile even when fully grown and able to breed. It is, in effect, a creature that never grows up – and it is also one of the strangest and most remarkable animals in the world.

The axolotl’s refusal to change its form is only the first of its peculiarities. Far more extraordinary is its power of regeneration. Where most animals can, at best, heal a wound, the axolotl can regrow entire limbs, its tail, and even parts of its heart, eyes and brain, rebuilding them perfectly and, astonishingly, without any scarring. A lost leg is replaced – bone, muscle and nerve – within weeks. This ability has made the animal the object of intense scientific interest, for researchers hope that understanding how it rebuilds itself might one day help in the treatment of human injuries. To keep those delicate gills supplied with oxygen, the axolotl remains always in the water, and it will never willingly leave it.

For all its wonders, the axolotl is in grave danger in the wild. The lakes it once inhabited have been drained and built over as Mexico City has spread across the valley, so that only a network of canals now remains, and much of its natural habitat has simply disappeared. The water that is left is badly affected by pollution, as waste from the surrounding city drains into it. And the animal faces a further threat from fish such as carp and tilapia, introduced to the canals, which eat its eggs and its young. As a result, the axolotl is now critically endangered in the wild, and recent surveys suggest that only a tiny number survive there.

It is a strange irony that a creature kept by the hundreds of thousands in laboratories and home aquariums around the world should be on the very edge of extinction in the one place it naturally occurs. The animals raised in captivity, however useful to science, cannot by themselves save the wild population, which is adapted to a particular place and carries a genetic diversity that the captive stock has largely lost. A wild species is more than a set of individuals; it is a population shaped by, and suited to, the exact conditions in which it evolved, and that cannot easily be rebuilt from animals bred for generations in tanks.

Efforts are now under way to prevent that loss. Conservationists, working alongside local farmers, have begun to clean stretches of the canals and to create refuges where the water is filtered and the introduced fish are kept out. Some of these projects draw on traditional methods of farming that have shaped the area’s waterways for centuries, using floating gardens to trap sediment and improve the water. Whether such efforts will be enough to secure the axolotl’s future is still uncertain.

What is certain is that a great deal would be lost with it. Few animals have so much to teach us about how bodies build and repair themselves; fewer still manage to be, at one and the same time, a laboratory marvel, a national emblem and one of the most endangered amphibians on Earth. The salamander that never grows up may yet run out of time.

You should spend about 20 minutes on Questions 14–26.

Farming in the city

The idea of growing food inside a building, stacked in layers from floor to ceiling, would once have seemed absurd. Farming needs soil, sunlight and open space – the very things a city lacks. Yet in warehouses, disused factories and even old shipping containers in cities around the world, crops are now being grown indoors, without soil and without sunlight, in what has come to be called vertical farming. Its supporters believe it could change the way cities feed themselves.

A vertical farm looks nothing like a field. Plants are grown in stacked layers, one above another, so that a small floor area can hold many times the growing space it would offer outdoors. In place of sunlight, the crops are lit by banks of LEDs, tuned to exactly the wavelengths the plants use best. There is no soil: instead the roots hang in, or are fed by, water enriched with nutrients – a method that uses far less water than ordinary farming, since the water is captured and circulated round the system again and again rather than draining away into the ground. Temperature, humidity and light are all controlled precisely, so the crops can be grown all year round, unaffected by weather, drought or season. And because the farm can sit in the middle of a city, the food travels only a short distance to reach the people who eat it, arriving fresh and without the long journeys most produce now makes.

There are other advantages. Sealed off from the outside world, the plants are not troubled by pests, so no pesticides are needed. Nothing is at the mercy of a bad summer or a late frost. For crowded cities with little spare land, and for regions where the climate makes ordinary farming hard, the appeal is obvious. Supporters point out, too, that a harvest grown a few streets from the shop that sells it need not be picked early and shipped across the world, so it can be fresher, and less of it is lost to spoilage along the way.

Yet vertical farming has serious limitations, and the greatest of them is energy. Sunlight is free; the artificial light and the climate control that must replace it are not, and the electricity a vertical farm consumes is enormous, making up much of its running cost and, unless the power comes from clean sources, much of its environmental impact too. There is also the question of what can be grown. The method suits fast-growing, lightweight crops such as leafy greens and herbs, but it cannot yet profitably produce the grains – wheat, rice and the like – that feed most of the world. The cost of building a vertical farm in the first place is very high, putting it beyond the reach of most ordinary growers. And the systems are delicate: a failure in the power supply or the pumps can ruin an entire crop within hours.

For these reasons, vertical farming is unlikely to replace the ordinary farm any time soon, and the fields that grow our staple foods are in no danger of disappearing. But as a way of supplying fresh salad leaves and herbs to a nearby city, all year round and on very little land, it has already found a place. Whether it grows into something larger will depend, above all, on whether the electricity it relies on can be made both cheap and clean. Until that happens, the vertical farm will remain a clever answer to a narrow question, rather than the revolution in food that its more enthusiastic backers sometimes promise.

You should spend about 20 minutes on Questions 27–40.

One thing at a time

It is one of the most prized skills of the modern workplace. Job advertisements demand it; we boast of it in interviews; we feel a certain pride as we answer an email with one hand, take a call with the other and keep half an eye on a meeting. Multitasking, we are told, is what a busy, capable person does, and the more of it we manage, the more we seem to achieve. There is only one problem with this flattering picture. According to a growing body of research, multitasking, in the sense we usually mean, does not really exist at all.

The belief in it has deep roots. As computers put more and more within reach of a single worker, and as the boundaries between separate tasks dissolved into one glowing screen, the ability to juggle many things at once came to seem not merely useful but essential – the very mark of the efficient, modern employee. Employers came to expect it, and workers, anxious to appear capable, came to claim it. A whole culture grew up around the idea that doing several things at once was simply a better and faster way to work.

The trouble is that the human brain is not built for it. Faced with two tasks that each demand attention, the brain does not run them side by side, as a computer runs two programs; instead it switches, rapidly and repeatedly, from one to the other, giving its full attention first to this, then to that. What feels like doing two things at once is in reality a fast alternation between them. We may combine an automatic activity with an attentive one – walking while talking, say – but two tasks that both require thought cannot truly be carried out together. One of them always waits.

And every switch has a price. In laboratory studies, people asked to switch back and forth between tasks consistently took longer to finish them, and made more mistakes, than those allowed to complete one before beginning the next. Each time attention moves, it must disengage from the first task and re-engage with the second, and though each shift takes only a fraction of a second, the fractions accumulate through a working day into a substantial loss. The juggler, it turns out, drops a great deal.

This hidden penalty has a name: the switching cost, the time and accuracy sacrificed every time the mind is pulled from one thing to another. It is largely invisible to the person paying it, which is exactly what makes it so dangerous. We feel busy and productive, and the feeling is quite real; but the sense of getting more done is, very often, an illusion. We are working harder in order to achieve less. What we notice is the effort and the motion; what we do not notice is the quiet toll that all that switching takes on the quality and speed of the work itself.

The evidence is not comfortable for those who take pride in the skill. Research on people who consider themselves strong multitaskers has repeatedly found that they are, if anything, worse at it than everyone else – more easily distracted, and poorer at filtering out what does not matter. Studies of drivers using a phone at the wheel have found their reaction times as slow as those of drivers who had been drinking. And research on office workers has shown that, after an interruption, it can take a surprisingly long time to return fully to the original task – far longer than the interruption itself lasted.

The lesson of all this is old-fashioned and rather dull, which may be why we resist it. We work better, faster and more accurately when we give a single task our whole attention, finish it, and only then turn to the next. Single-tasking lacks the glamour of the juggling act, and it will never look as impressive to anyone watching. But it is the way the mind is built to work – and, in the end, it is the way to get more done.