IELTS Academic Reading Practice Test 70

The word denim refers to a sturdy cotton fabric most closely associated with blue jeans, but its origins lie in Europe. The name is generally traced to Nîmes in southern France, where a hard-wearing cloth known as serge de Nîmes was produced. A similar material was already being made in Genoa, Italy, and used for work clothes, particularly by sailors. The English word jeans is thought to derive from the French name for Genoa, Gênes. By the eighteenth century, such fabrics were imported into Britain and valued for their durability rather than their appearance.

The modern garment began to take shape in the United States during the nineteenth century. Levi Strauss, a Bavarian-born merchant who sold dry goods in San Francisco, supplied canvas and later denim to miners and labourers. In 1872 a tailor named Jacob Davis, who had been making work trousers reinforced with copper rivets at points of strain, proposed a partnership because he lacked the money to file a patent. The two men received United States patent 139,121 in 1873 for riveted waist overalls, and the product that became known as blue jeans was born.

Denim is usually woven as a twill, a structure that gives the cloth its characteristic diagonal lines. In the most common form, the warp threads, which run lengthwise, are dyed with indigo, while the weft threads, which run across the fabric, are left white. Because the warp is carried over several weft threads, the surface appears mostly blue, while the underside is much paler. When the fabric is abraded, the white weft gradually becomes visible, which is why well-worn jeans fade in the way they do. The weight of denim is traditionally measured in ounces per square yard.

Indigo, the dye that gives denim its deep blue colour, was originally extracted from plants of the genus Indigofera. The dye is unusual because it does not penetrate cotton fibres completely; instead it adheres to their outer layers. This explains why denim fades with repeated washing and wear. In the late nineteenth century the German chemist Adolf von Baeyer worked out the structure of indigo, and synthetic production was developed commercially shortly afterwards. By the early twentieth century most denim was dyed with synthetic indigo, which offered consistent colour at a lower cost.

Manufacturing denim involves several stages. After cotton is harvested and ginned, the fibres are carded and spun into yarn. The warp yarn is then dyed with indigo, often by passing it repeatedly through several vats, a process known as rope dyeing. The dyed warp is woven with undyed weft on a loom. The resulting fabric is inspected, brushed and singed to remove loose fibres, and then sent to finishing. At this stage mills apply chemical treatments to give the denim particular qualities, such as softness, stiffness or resistance to shrinking.

One of the most important finishing processes is sanforization, named after the American businessman Sanford Lockwood Cluett. In this mechanical treatment the fabric is dampened and compressed between rollers under controlled conditions. The aim is to shrink the cloth before garments are cut and sewn, so that jeans do not shrink significantly when the customer washes them. Sanforized denim is described as pre-shrunk. Without such treatment cotton denim can shrink by several per cent on its first wash, changing the fit of a garment.

Jeans were originally sold stiff and dark, and wearers softened them through use. In the 1970s fashion demanded a broken-in look, and manufacturers began to wash garments before sale. Stone washing used pumice stones in industrial washing machines to abrade the surface and produce a faded appearance. Later, enzymes were introduced to achieve similar effects with less damage to fabric and machinery. Today manufacturers also use laser techniques to create worn patterns precisely, reducing the quantity of water and chemicals needed.

In the 1950s, blue jeans became a symbol of teenage rebellion after actors wore them in popular films. This association alarmed some adults, and schools in several countries briefly banned denim. Over following decades, designers turned workwear into high fashion, and jeans were adopted by people of every background. Their transformation from labourers' clothing to a global wardrobe staple illustrates how a practical fabric can acquire unexpected social meaning.

The environmental footprint of denim production has attracted criticism. Growing cotton requires large volumes of water and may involve pesticides. Dyeing and finishing consume still more water, and many of the chemicals used must be managed carefully to prevent pollution. The industry has responded with programmes to reduce water use, recycle processing baths and develop less toxic dyes. Some mills now claim to make jeans using only a small fraction of the water once required, though critics argue that the true cost also includes the energy used in transport and laundering.

Today jeans are produced in enormous quantities and worn in almost every country. Stretch denim, which incorporates a small amount of synthetic fibre, has made the garment more comfortable, while constant changes in cut and finish keep it relevant to each generation. From its beginnings as workwear for miners, denim has become a global cultural symbol, associated at different times with youth, rebellion and everyday practicality. Few materials can claim to have shaped modern dress so thoroughly.

The life cycle of Pacific and Atlantic salmon is among the most demanding in the animal kingdom. Salmon hatch in freshwater streams, spend their early months or years there, and then migrate to the ocean, where they may travel thousands of kilometres before returning to breed. Most adult salmon return with remarkable precision to the same river, and often to the same tributary, in which they were born. This behaviour, known as homing, has fascinated scientists for more than a century and has proved central to the management and conservation of salmon populations.

The homing ability of salmon has been demonstrated repeatedly. In the 1950s, scientists marked thousands of young fish by clipping their fins and later recovered adults in the streams where they had been released. More recently, studies using tiny tags have shown that some individuals return not only to the same river but to within a few metres of the spot where they hatched. Such precision is all the more striking because a young salmon may spend up to several years at sea, travelling far from its birthplace, before returning.

The leading explanation for homing is that young salmon learn the chemical signature of their birthplace. During a period of physiological change known as smoltification, when a juvenile salmon adapts to life in salt water, its brain becomes especially sensitive to odours. As the fish moves downstream, it stores a memory of the unique mixture of substances washed from the soils, plants and rocks of its home stream. This process is called olfactory imprinting. When the adult fish returns from the ocean, it follows this odour trail upstream, often navigating through complex river networks to the exact site where it hatched.

Olfaction alone, however, cannot explain how salmon locate the mouth of their home river in the open ocean. In recent years, scientists have proposed that salmon also imprint on the magnetic field of the Earth. The planet's magnetic field varies from place to place, so each section of coastline has a distinctive magnetic signature. Experiments suggest that juvenile salmon can detect changes in magnetic intensity and use this information to remember the location of their natal stream. Later, as adults, they may use the same cue to return to the general area of that stream before switching to chemical signals for the final stage.

The homing system is therefore thought to involve a sequence of cues. In the open ocean, salmon may combine magnetic, celestial and possibly current-related information to maintain their direction. As they approach the coast, they enter waters carrying the chemical signature of their home river and can begin to follow odours. Finally, within the river system itself, they respond to smaller-scale chemical differences between tributaries. This layered use of cues makes homing robust: if one signal is disrupted, the fish can often still locate their destination using the others.

Homing is not perfect. A small proportion of salmon, known as strays, return to rivers other than their birthplace. Straying is not necessarily harmful, because it allows salmon to colonise new habitats and maintains genetic diversity among populations. The rate of straying varies by species, by river and by environmental conditions. Chum and pink salmon, for example, tend to stray more often than some other Pacific species, while natural disturbance or strong currents can push returning adults away from their intended stream.

Human activities have altered the cues on which salmon depend. Dams and weirs block migration routes, and reservoirs can change the chemical signal of a river. Pollution, including agricultural runoff and industrial discharge, may mask or alter the odours that guide returning fish. Climate change further complicates homing by warming rivers, changing flows and shifting the timing of smoltification. In some regions, hatchery programmes have produced large numbers of fish with weaker imprinting, and such fish tend to stray more often than wild salmon, raising concerns about the genetic mixing of distinct populations.

Because homing maintains the separation of salmon populations, each of which is finely adapted to its own environment, the loss of homing fidelity can have serious consequences. If fish from a warmer river stray into a colder one, for example, their offspring may be less suited to local conditions. Conservationists therefore try to protect both the physical routes that salmon use and the chemical information that guides them. This can involve removing barriers, restoring natural flows and limiting pollutants that interfere with olfaction.

Future research may refine the picture of how salmon navigate. Laboratory studies continue to explore the magnetic sense, while genetic tools allow scientists to compare the homing behaviour of wild and hatchery fish in detail. The challenge is to translate this knowledge into practical measures. Protecting salmon may require not only clean water and open rivers but also an understanding of the invisible cues that link a fish to the stream in which its life began.

Esports, or competitive video gaming, has grown from a small hobby into a large global industry. Big events fill large arenas and are watched online by hundreds of millions of people over a season. This rise has made sports officials, teachers and parents ask whether esports is a real sport, a form of entertainment, or something in between. In my view, esports is a distinct competitive activity that shares some features with sport but also differs from it in important ways.

The roots of esports lie in arcade competitions in the late 1970s and early 1980s, when players competed for high scores on games such as Space Invaders. The modern era is usually dated to the late 1990s in South Korea, where professional leagues for strategy games emerged alongside dedicated television channels and player salaries. Investment in broadband internet helped make esports a mainstream spectator activity, and this model soon spread. South Korea's success showed that esports could attract large live audiences and become a stable profession.

Today's esports industry is built around publishers, leagues, teams, sponsors and streaming platforms. Game developers own the games and often control tournament rules. Teams employ coaches and analysts, while sponsorship and media rights generate revenue. Advertising and merchandise sales also bring in money. Streaming services let fans watch live and interact with players, a feature that separates esports from many traditional sports. Top prize pools are worth millions of dollars, and a few leading players earn very high incomes.

Comparisons with traditional sport are natural. Esports competitors train for many hours a day, analyse opponents and develop team strategies. The games demand fast reaction times, precise hand-eye coordination and sustained concentration. Supporters say that precision and mental endurance are forms of skill, even if they are not the same as running speed or strength. Critics note that physical effort is far lower than in most recognised sports, and that rules and equipment are owned by private companies rather than controlled by independent bodies. These differences matter when Olympic inclusion is discussed.

A more serious concern is player welfare. Professional players often begin intensive practice in their mid-teens and may spend ten or more hours a day in front of a screen. Clinicians have reported repetitive strain injuries, eye strain, sleep disturbance and psychological burnout among young competitors. Careers are often short, and some players lack other qualifications. A few teams limit practice hours and employ health staff, but such safeguards are not yet universal. Physical and mental health support remains uneven across the industry. Players often retire in their early twenties due to these demands.

The appeal of esports to young people has attracted traditional sports organisations. Several professional football clubs and basketball franchises have created esports divisions, and universities offer scholarships for competitive gamers. Broadcasters value esports because it reaches viewers who do not watch normal TV. This commercial interest has pushed the call for recognition, but it raises questions about whether sports bodies are chasing young audiences rather than really helping players develop.

The question of Olympic recognition shows the tensions. The International Olympic Committee (IOC) has accepted the size of esports and discussed partnerships, but it is still careful about games that do not fit traditional ideas of sport. At the 2022 Asian Games, held in Hangzhou in 2023, esports events appeared as official medal competitions for the first time. One shooting game was included only in a modified version with less realistic violence, reflecting wider concerns about gaming content. The IOC has said that violent games are not suitable for the Olympics. Such compromises suggest that sports bodies are willing to work with esports, provided worries about content and control are addressed.

Critics also argue that business control makes esports open to abuse. Because one company typically controls a game, players may have little power to negotiate rules or income sharing. Teams can be closed overnight, and lower-level players often work without minimum pay. Worker groups have called for standard contracts, independent settlement and limits on practice time. Some countries have started to discuss labour laws for esports players. Without such rules, the growth of esports risks repeating mistakes seen in other entertainment industries.

Dismissing esports as just time on screens would be a mistake. The skills it develops, including strategic thinking, communication and adaptation under pressure, are real and transferable. In some countries, schools run esports clubs to teach teamwork and computer skills. These benefits suggest that esports is more than a business product. The challenge is not to decide whether esports is exactly the same as football, but to build a system that protects players while allowing competition to grow.

I believe esports should be taken seriously as a legitimate form of competition, but its inclusion in the category of sport should depend on clear standards for player welfare, governance and integrity. If those standards are met, esports can be placed alongside other activities that require skill, training and dedication, without pretending to be something else. In the end, the debate should focus on creating fair conditions for players, not on whether the activity fits a single label.