IELTS Academic Reading Practice Test 136

Long before anyone spoke of email, computer users were leaving messages for one another. From 1965, people working on the Compatible Time-Sharing System at the Massachusetts Institute of Technology could type a command that placed a short note in another user's file space on the same machine, and similar facilities appeared on other large computers. These early messages, however, never travelled beyond a single machine, and the person receiving one had to be logged in to the same system. The decisive step was to send a message between two computers linked by a network.

That step was taken by Ray Tomlinson, an engineer at Bolt Beranek and Newman, a computing firm in Cambridge, Massachusetts. The firm had helped to build ARPANET, the network that first connected computers at several American research sites in 1969. Tomlinson had written a program called SNDMSG that allowed users of one machine to leave messages for colleagues. In 1971 he adapted it, combining it with an experimental file-transfer program so that a message could be delivered to a mailbox on a distant computer. A way was needed to separate the name of the user from the name of the computer, and Tomlinson chose the @ symbol, which was unlikely to occur in anyone's name and could be read as 'at'. The first message was sent between two machines standing side by side; Tomlinson later admitted that he could not remember what it said.

ARPANET grew quickly, and electronic mail grew with it. By the mid-1970s messages between users accounted for the greater part of the network's traffic, a proportion that surprised its designers, who had expected file transfer and remote login to dominate. Mailing lists appeared, allowing a single message to reach a group of subscribers interested in a particular subject. Commercial and political messages soon followed: in 1978 a marketing manager named Gary Thuerk used an ARPANET directory to send an advertisement for computer equipment to several hundred addresses, an event often described as the first spam.

These messages were exchanged by a patchwork of programs that did not always understand one another. An address that worked on one system might be rejected by another, and there was no agreed format for the information at the top of a message. The solution came in 1982, when two documents published by the internet research community defined a common method. One described the Simple Mail Transfer Protocol, the rules by which one computer hands a message to another; the other set out the structure of the message itself, with fields for the sender, the recipient, the date and the subject. The first was written by Jon Postel, a central figure in the development of the early internet, and the second by David Crocker; together they allowed quite different machines to exchange mail reliably.

Meanwhile electronic mail had been escaping the laboratory. In March 1976, during a visit to the Royal Signals and Radar Establishment at Malvern in England, Queen Elizabeth II sent a message over ARPANET, becoming the first head of state to do so. The same period saw the growth of commercial services, which allowed subscribers with ordinary telephone lines and modems to exchange mail; CompuServe, one of the largest, began offering electronic mail in 1979, and America Online brought the idea to millions of households in the 1990s. For most of these users the appeal was practical rather than technical: a letter could arrive in seconds, and a reply could be sent the same day.

Two further changes made email resemble what we use today. The first was the attachment. For years, mail systems carried text only, and sending a photograph or a spreadsheet required cumbersome encoding by hand. In 1992 a group of engineers, led by Nathaniel Borenstein and Ned Freed, published a standard called MIME, which allowed a message to carry images, sound recordings and text in languages other than English, and to identify what each part contained. The second was the spread of web-based mail in the late 1990s, which freed users from a particular computer and allowed them to read their messages from any machine connected to the internet.

The consequences for working life were considerable. Because a message could be sent to many people at once and answered at any hour, the boundary between the office and the home became less clear, and employees in many industries came to be expected to read mail in the evening. Researchers who study workplace communication have argued that the constant arrival of new messages fragments attention, since each one invites at least a glance. Yet the same technology allowed teams spread across continents to work together, and it remains the backbone of much commercial and official business.

Email also changed the way people wrote. Because a message could be composed quickly and answered within minutes, it developed a style of its own: shorter sentences, less formal greetings and a tolerance of minor error that would have been unthinkable in a business letter. Historians of technology have observed that a network's users shape its purposes as much as its designers do, and email is the clearest example.

Another consequence was less welcome. Because sending a message cost almost nothing, the volume of unwanted mail rose steadily, and with it came fraud. The 'phishing' message, which invites the recipient to click a link and enter a password or a bank detail, is now a standard tool of criminals, and organisations spend large sums on filters and staff training. The @ sign itself, once used mainly in accounts, has become so closely associated with the technology that the Museum of Modern Art in New York added it to its collection in 2010.

Meat is produced today by raising animals and slaughtering them, a system that uses large areas of farmland, consumes vast quantities of water and generates significant greenhouse gases. Cultivated meat, also called cultured or cell-based meat, is an attempt to obtain the same food by growing only the part that is eaten. Instead of a whole animal, producers grow muscle tissue from a small sample of cells inside a factory. The promise is a product that tastes like meat, can be made close to the cities where it is sold, and requires far less land.

The process begins with a biopsy. A veterinarian removes a piece of muscle, usually a few grams, from a living animal under local anaesthetic, and the wound heals quickly. The sample contains satellite cells, a type of stem cell that sits beside muscle fibres and repairs them after injury. In the body these cells are mostly dormant. In the laboratory they are placed in a warm nutrient solution and encouraged to divide, and because each cell can give rise to two more, a small sample can in principle be expanded into an enormous population.

Feeding those cells is the hardest part. They require sugars, amino acids, vitamins, salts and, above all, growth factors: proteins that signal a cell to divide. For decades biologists cultured animal cells in fetal bovine serum, a fluid collected from the blood of slaughtered pregnant cows. Serum is expensive, varies from batch to batch and is ethically awkward, and a product that depends on it can hardly be described as animal-free. Much recent work has therefore gone into serum-free recipes, in which growth factors are manufactured by genetically modified bacteria or yeast, or replaced by plant extracts. The cost of the medium remains the largest single obstacle to cheap production.

The cells are multiplied in bioreactors, stainless-steel vessels in which temperature, acidity and dissolved oxygen are carefully controlled and the liquid is continuously stirred. Most companies use stirred-tank reactors adapted from the brewing and pharmaceutical industries. Because muscle cells prefer to attach to something, they are often grown on tiny spheres called microcarriers that remain suspended in the liquid. The engineering challenge is scale: a vessel of a few thousand litres is modest by the standards of industrial fermentation, yet keeping it sterile and well mixed for weeks is far from simple.

Harvesting the cells is only half the task, because a loose collection of cells has the texture of paste. To make something that can be chewed, the cells must fuse into fibres and line up in the same direction. Producers therefore grow them on scaffolds, which may be made of edible collagen, plant protein or other materials, and sometimes stretch the developing tissue or pass a small electric current through it. Products such as mince, nuggets and sausages are much easier to make than a steak, and many companies mix cultivated cells with plant protein.

The idea was demonstrated in 2013, when Mark Post of Maastricht University presented a hamburger to journalists in London. It had been assembled from about twenty thousand small strips of beef grown over several weeks in his laboratory, and the project was reported to have cost around 250,000 euros, paid for by the internet entrepreneur Sergey Brin. The burger was cooked and tasted on camera. It proved that the concept worked and, at the same time, showed how far it was from the supermarket shelf.

Regulation has begun to catch up. In 2020 Singapore became the first country to approve the sale of a cultivated meat product, chicken made by the company Eat Just. In 2023 regulators in the United States cleared products from two firms, UPSIDE Foods and GOOD Meat, after separate reviews of their safety by the food agency and the agriculture department. Several other countries are developing their own frameworks. Sales so far are tiny, limited to a handful of restaurants.

The environmental case is less clear-cut than early enthusiasts suggested. Growing cells in warm, sterile tanks for two or three weeks uses a great deal of electricity, and the medium and the cleaning chemicals carry their own footprint. Analyses published in recent years disagree about whether cultivated meat would produce fewer emissions than beef, pork or chicken, and much depends on how the power is generated. Reviews of such studies generally conclude that the advantage would be largest compared with beef, and smallest, or even negative, compared with chicken.

Research now concentrates on a few stubborn problems. One is the cell line: scientists want cells that will divide indefinitely without becoming cancerous or losing their ability to form muscle. Another is the medium, where cheaper growth factors would transform the economics. A third is the scaffold, which ideally would be edible, cheap and able to give the right texture. Several teams are also applying the techniques to fish, whose muscle cells are in some ways easier to grow.

Consumer acceptance is another unknown. Surveys in several countries suggest that younger, urban shoppers are more willing to try cultivated meat than older consumers in rural areas, but stated intentions are a poor guide to what people actually buy. Several jurisdictions have debated how such products may be labelled, and in a few, sales have been restricted altogether.

Few everyday transactions now begin with a face-to-face meeting. Opening a bank account, renting a flat or buying a mobile phone contract all require proof of identity, and increasingly that proof is demanded online, at a distance, by an organisation that has never met the applicant. Digital identity systems are the response: a way of proving who you are over the internet with something like the confidence of a passport presented across a counter.

The typical system rests on a registration carried out once, in person, at which a government office records a name, a date of birth, an address and often a photograph and fingerprints. These details are then linked to a credential held on a phone or a smart card. The credential contains cryptographic keys rather than a copy of the data, so that the holder can prove an attribute, such as being over eighteen, without disclosing a birth date.

The advantages are real. Estonia, which introduced a compulsory identity card with a digital signature in 2002, allows residents to file taxes, sign contracts, collect prescriptions and vote online, and the card is used millions of times a year. Digital signatures also reduce fraud, because a signature can be verified by anyone and a stolen password is of little use without the physical card and its codes. For people who lack a birth certificate or a fixed address, a well-designed scheme can be the first official record of their existence, and therefore a route into banking and benefits.

Critics reply that a single credential for every service is a single point of failure. A system that knows where you bank, when you see a doctor and whom you voted for is a tempting target for criminals and a powerful instrument for any government inclined to abuse it. The danger is rarely the purpose for which a scheme was created; it is the purposes added later, a process that civil liberties groups call function creep. Once the infrastructure exists, refusing to connect it to a new database becomes politically difficult.

India's Aadhaar scheme, which has enrolled more than a billion people using fingerprints and iris scans, illustrates both sides. It has made it easier for millions to open accounts and receive payments, and it has also produced well-documented cases of people denied food rations because their fingerprints would not register or their details did not match. In 2018 the country's Supreme Court upheld the scheme as constitutional but struck down the provision that had allowed private companies to insist on it. The judgment reflected a wider truth: the same database can be a ladder or a gate, depending on the rules attached to it.

Estonia's experience shows that digital identity is only as trustworthy as its engineering. In 2017 researchers discovered a flaw in a chip used in identity cards around the world, and Estonia responded by blocking the affected certificates and requiring hundreds of thousands of cards to be updated. The episode damaged confidence, but it also demonstrated the value of a system that could be repaired quickly, because the flaw was made public and the response was coordinated.

Cost is another consideration that is easily overlooked. A scheme that requires a smartphone, a reliable connection and a fee for replacement documents excludes precisely the people who most need a secure identity. When a card becomes the only key to a service, every failure of the technology becomes a denial of the service itself.

Biometrics add a further complication. Fingerprint and facial recognition systems are convenient, but they fail more often for elderly people, for manual workers whose skin is worn, and for some ethnic groups, and a false match cannot be revoked in the way that a password can. A scheme that relies on a single biometric therefore builds in an error rate that falls unevenly across the population.

Britain's attempt to introduce identity cards between 2006 and 2010 ended in abolition. The scheme was expensive, its database was repeatedly delayed, and the obligation to attend an interview and pay a fee fell hardest on the poor. Its opponents argued that the card was a solution in search of a problem, and the coalition government that took office in 2010 repealed the legislation. The episode is a warning that public consent cannot be assumed, however good the technology.

My own view is that the case for digital identity is stronger than its opponents allow, but only under conditions that few schemes have yet met. A digital identity should be voluntary for access to ordinary services, with a paper or in-person alternative that is genuinely usable. It should store as little as possible, preferably on the holder's device, and disclose only the attribute a service needs. Its uses should be fixed in law, with an independent body able to refuse extensions. Every citizen should also be able to see who has checked their identity and why.

None of this is technically difficult. The cryptography is well understood, and the standards exist. What is difficult is the politics, because the decisions that matter are not about algorithms but about power: who may ask for proof, what they may learn and what happens when they are wrong. A digital identity card is not inherently liberating or oppressive. It is a tool, and like every tool its effects will depend on the hands that hold it and the rules that bind them.