IELTS Academic Reading Practice Test 89

Alexandria was founded on the Mediterranean coast of Egypt by Alexander the Great in 331 BC, and after Alexander's death it became the capital of the Ptolemaic kingdom. The city's Greek-speaking rulers built a palace quarter that included a shrine to the Muses, known as the Mouseion, and beside it a great library. Most accounts associate the library's creation with the first two Ptolemies, Ptolemy I Soter and his son Ptolemy II Philadelphus, in the early decades of the third century BC. It was probably begun as a home for the texts that Greek scholars would need as they pursued literature, science and philosophy.

The first Ptolemies had an unusually ambitious goal: to gather every book in the inhabited world. Royal agents travelled to the established book markets of Athens, Rhodes and other Mediterranean cities, where they purchased whatever they could find. According to later authors, the harbour authorities were also instructed to search ships arriving in Alexandria. If scrolls were discovered, they were taken to the library, copied with care, and the copies were returned to their owners while the originals were kept. This policy, however exaggerated it may be in the surviving sources, reflected the conviction that a comprehensive collection would serve both royal prestige and scholarly work.

The number of scrolls in the collection is impossible to establish. Ancient writers give figures that range from perhaps 40,000 to as many as 700,000, and even the lower totals are far larger than any earlier collection. What is clearer is that the Ptolemies' collecting extended beyond Greek literature to include works from Egypt, Mesopotamia, Persia and Judaea, some of which were translated into Greek. The Hebrew scriptures, for example, were said to have been rendered into Greek at Alexandria in the translation that became known as the Septuagint, although the details of that project are also much debated.

A collection of this size required organisation. The scholar-poet Callimachus, who worked at the library in the third century BC, compiled the Pinakes, a vast biographical and subject catalogue of Greek literature, which is often described as the first serious attempt at bibliography. Other leading intellectuals were appointed as head librarians in succession. Zenodotus of Ephesus produced an edition of Homer, and Eratosthenes calculated the circumference of the Earth with remarkable accuracy. Aristarchus of Samos, another figure associated with Alexandria, proposed that the Earth revolved around the Sun, an idea that failed to persuade most ancient astronomers but anticipated later discoveries.

The library was damaged several times, but no single disaster explains its disappearance. During Julius Caesar's campaign in Alexandria in 48 BC, fire spread from ships in the harbour and, according to several ancient writers, destroyed some of the library's scrolls. However, the library clearly continued to operate long afterwards, so the fire may have consumed only part of the collection or only a warehouse near the harbour. Under the Roman Empire, Alexandria remained a centre of learning, and later emperors are known to have made gifts to the institution.

A far graver blow came at the end of the fourth century AD, when the Roman Empire was becoming officially Christian. In 391 AD the Serapeum, a great temple in Alexandria that had come to house a branch of the library, was demolished after the emperor Theodosius I prohibited pagan religious practices. The destruction of the Serapeum and its associated collection was remembered by Christian and pagan writers alike as a severe cultural loss.

A much later story claims that the library was finally destroyed when Arab armies took Alexandria in 642 AD. The tale is best known in a version in which the Arab commander asks the caliph what should be done with the books and receives the reply that they are unnecessary if they agree with the Koran and harmful if they do not, so they are burnt to heat the city's baths. Modern historians have found no reliable contemporary evidence for this story, and it is generally regarded as a legend that took shape centuries after the conquest.

The consensus among scholars is therefore that the great library did not end in a single blaze. It probably declined over many generations as royal and imperial support weakened, as parts of the collection were dispersed or damaged, and as the papyrus scrolls themselves decayed. In Alexandria's climate, where humidity is high, papyrus survives poorly unless it is kept dry and copied frequently. By the time of the Arab conquest, the famous library appears to have been little more than a memory.

Its influence, however, long outlasted the institution. The library's model of systematic acquisition, copying and cataloguing shaped later libraries in Rome, Constantinople and the medieval Islamic world. More importantly, the scholarship carried out there preserved and standardised much of the Greek literature that later ages read. The loss of the Alexandrian library has often been treated as an emblem of the fragility of knowledge, but the real history is not the story of one great fire. It is the quieter story of how an institution slowly lost the conditions that had allowed it to thrive.

Inside the large intestine lives one of the densest groups of microbes on Earth. Bacteria dominate this group, but archaea, viruses, fungi and other single-celled organisms are also present. Once it was said that such microbes outnumber human cells by ten to one, but a newer estimate puts the two at nearly equal numbers, about 38 trillion bacteria and 30 trillion human cells. Even so, the total microbial genome, often known as the microbiome, holds many times more genes than the human genome, and these genes provide skills our own cells lack. These microbes are not simply passengers; they help with many body tasks.

A person's gut microbes start to form at birth. Babies born through the birth canal meet their mother's vaginal and intestinal microbes first, while those born by caesarean section tend to pick up skin and environmental microbes. Breastfeeding, weaning, household contacts and antibiotics all leave marks on the growing ecosystem. By around age three the mix is mostly stable, though it can shift later with diet, illness and drugs. Birth mode has been linked in some studies to later allergy risk, but such links do not prove cause.

The clearest role of gut microbes is digestion. Many plant carbohydrates, especially the complex dietary fibres, pass unchanged through the small intestine and reach the colon, where bacteria ferment them. This process makes short-chain fatty acids such as acetate, propionate and butyrate. Butyrate in particular serves as a major energy source for the cells lining the colon and helps to maintain the gut barrier. The same microbes also make some vitamins and alter plant compounds that may affect health. Some bacteria also break down mucus, and the products enter the blood and can signal to distant organs.

The immune system is closely linked to gut microbes. Animals raised in sterile rooms, with no microbes at all, have weak immune organs and fewer of certain immune cells. When normal gut bacteria are added, parts of their immune function improve. This suggests that the microbiota helps train the body's defences. In healthy people, the immune system tolerates resident microbes while still attacking pathogens, and loss of this balance has been linked to some inflammatory diseases. Certain gut bacteria have been shown to promote particular immune cells in laboratory animals.

Studies have often found that people with conditions such as inflammatory bowel disease, obesity, type 2 diabetes and asthma have gut communities unlike those of healthy people. For example, the variety of bacterial species is often lower in some chronic diseases. However, the presence of an altered microbial community does not prove that it caused the disease. In many cases it may be a consequence of the disease itself or of the treatments, diets and lifestyles associated with it. This gap between correlation and causation is central to the field.

Microbes may also act beyond the gut. Tests on rodents show that animals without normal gut microbes respond oddly to stress and show altered behaviour, and that microbes from stressed animals can pass some of these changes to germ-free animals. In humans, researchers have found links between gut microbes and disorders such as depression and anxiety, but the evidence is largely observational. It is not yet clear whether changes in gut bacteria cause these conditions or simply accompany them. Researchers have also looked at the vagus nerve and microbial products, but mechanisms remain unclear.

Diet is one of the strongest influences on the gut microbiota within a person's life. People who eat a varied diet rich in vegetables, legumes, whole grains and fermented foods tend to have a wider range of bacterial species than those who eat highly processed foods. When volunteers switch for a short time to an extreme diet, changes in gut microbes can appear within days, though people vary. Repeated courses of broad-spectrum antibiotics can reduce microbial diversity for months or more, but recovery usually occurs. In controlled diets, shifts toward bile-loving species have been seen after diets very high in animal products.

The clearest medical use of microbiome science so far is faecal microbiota transplantation, or FMT. In this procedure, stool from a carefully screened healthy donor is processed and introduced into the intestine of a patient, usually through a colonoscopy or a capsule. FMT is now accepted for recurrent infection with the bacterium C. difficile, a condition that can be hard to cure with antibiotics alone. The added microbes seem to restore competition and metabolic balance, but the method carries risks, and regulators require donor material to be tested for infections. In many hospitals, FMT is now used after standard antibiotic courses have failed.

Commercial products have moved faster than the evidence. Shops now sell probiotics, prebiotics and home gut health tests, but the effects of particular probiotic strains are often small and specific, while home test results are hard to interpret. Researchers stress that the field is still young. They see promise in using microbiome data to plan more personal diets and in finding microbial markers that predict disease, but they warn against treating every link as a cause. For now, consumers should approach many of these products with caution. Most commercial probiotics contain common bacteria, but their benefit for healthy people is not established.

Few educational debates recur with such regularity as the question of whether boys and girls should be educated separately. Advocates of single-sex schools often insist that the sexes develop at different rates and therefore need different teaching, while critics reply that segregation is both socially retrograde and unsupported by evidence. The dispute arouses strong feelings among parents, teachers and policymakers because it touches immediate decisions about where individual children will spend their school years. Yet the research literature, as I shall argue, offers far less support for either strong position than is commonly assumed.

Single-sex schooling is hardly a new experiment. It was for centuries the dominant model in many parts of the world, and it remains widespread in several countries, either in independent schools or in publicly funded systems. During the twentieth century many state systems moved towards coeducation, partly for reasons of cost and convenience and partly from an egalitarian belief that boys and girls should learn together. More recently, however, interest in separating the sexes has revived in a number of places, especially in the United States, the United Kingdom and Australia, often in response to worries about boys' underachievement or girls' participation in science and mathematics. In some systems the two models now coexist, which makes direct comparison easier in principle but still difficult in practice.

A common justification for this revival is that neuroscientific research has shown that male and female brains are fundamentally different. It is true that group-level differences have been reported in aspects such as the timing of brain maturation and the size of certain structures relative to total brain volume. However, the variation within each sex is very large, and the distributions for boys and girls overlap heavily on almost every measure. Most neuroscientists therefore caution that brain research cannot tell teachers how to instruct a particular child, and that general statements about so-called male brains and female brains are a weak basis for organising schools. Brain scans reveal overlapping distributions, not two distinct categories.

The core empirical question is whether children achieve more in single-sex classes. Many studies have found that pupils in single-sex schools obtain somewhat higher examination scores on average, and these findings are sometimes used to support the model. But such comparisons are difficult to interpret. In most countries the pupils who attend single-sex schools are not randomly assigned: their families have chosen the schools, and those families may differ from the general population in income, education and academic expectations. Single-sex schools also tend to be selective or to enrol pupils from particular social groups, so any observed advantage may simply reflect the composition of the student body.

When researchers attempt to control for prior attainment and family background, the differences usually become small and often disappear altogether. Reviews that combine many studies, known as meta-analyses, generally report either no significant overall advantage for single-sex schooling or effects so modest that they would make little practical difference in the classroom. One influential analysis of studies published over several decades found that the apparent benefits were smallest in the most rigorous studies, while weaker designs produced larger effects. This pattern strongly suggests that selection, not separation, explains much of the headline difference.

Supporters nevertheless argue that single-sex environments have particular benefits in specific subjects. It is sometimes claimed that girls in girls-only classes are more willing to choose physics, advanced mathematics and computer science, while boys in boys-only classes become more engaged in reading and languages. Some studies do find such patterns, but the results are inconsistent, and few have followed pupils over long periods. Long-term evidence on subject choice remains particularly limited. Moreover, any gains in subject choice may reflect school ethos, staffing or timetabling rather than the absence of the other sex.

The social consequences of separating boys and girls are even harder to evaluate. Opponents argue that single-sex schooling can strengthen gender stereotypes, because pupils receive the implicit message that the two sexes cannot learn together or that they need different treatment in all domains. Some research has found that children in single-sex schools express more stereotyped attitudes or show less ease in mixed-group activities, but the evidence is fragmentary. What is certain is that pupils in single-sex schools have fewer routine opportunities to work with the other sex, and this may matter in societies where adults are expected to cooperate in mixed workplaces and communities.

If school type mattered strongly, its effect should be visible even after the quality of teaching, curriculum and school leadership are considered. In practice, these factors appear to be far more powerful than whether a school is single-sex or coeducational. Effective feedback, clear explanations, high expectations and strong relationships between teachers and pupils benefit learners of both sexes. It is therefore plausible that many of the successes attributed to single-sex schools come not from separation itself but from the fact that such schools are often smaller, better resourced or more academically focused.

My conclusion is not that single-sex education should be banned, nor that no child benefits from it. Families may choose such schools for cultural, religious or personal reasons, and some pupils may feel more comfortable in a single-sex environment. But the policy claim that separating boys and girls reliably raises achievement is not well supported. Educators and parents should be wary of treating sex as the most important fact about a learner, and should focus instead on the less dramatic features of schooling that evidence consistently links to learning.