Reading Lab

IELTS Academic Reading Practice Pack 26

A rebuilt Academic Reading set on the microbiome, the philosophy of time, and deep-sea mining, repaired to full production structure.

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60 min

Passages

academicreadingfull mockmicrobiologyphilosophy of physicsmarine governanceqa candidate

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Passage 1

The Microbiome: The Ecosystem Within

How the human microbiome influences immunity, behaviour, and medicine, and why the body's ecological partnership with microbes complicates the boundary between self and non-self.

A.A The human body is home to trillions of microorganisms -- bacteria, viruses, fungi, and archaea -- that collectively constitute what scientists call the microbiome. Estimates suggest that the number of microbial cells in and on the human body approximately equals the number of human cells, a ratio that has been revised downward from earlier claims of ten-to-one but remains strikingly large. These microorganisms are not passengers; they are active participants in processes ranging from digestion to immune regulation to mood. The gut microbiome -- the community of microorganisms inhabiting the gastrointestinal tract -- has attracted particular scientific attention as its importance to human health has become progressively clearer.

B.B The relationship between humans and their gut microbiota is one of mutual dependence. Gut bacteria break down dietary fibre into short-chain fatty acids that provide energy for intestinal cells and perform anti-inflammatory functions. They synthesise vitamins, including vitamin K and several B vitamins, that humans cannot produce themselves. They train the immune system to distinguish between harmful pathogens and harmless antigens, a process that begins at birth and continues throughout infancy. Infants delivered by caesarean section, who are not exposed to the maternal vaginal microbiome during birth, show differences in gut microbial composition that persist for months and have been associated, though not definitively causally linked, with modestly elevated rates of allergic and autoimmune conditions.

C.C The composition of the gut microbiome varies substantially between individuals and is shaped by a combination of genetic, environmental, and dietary factors. Diet is among the most powerful short-term modulators: clinical studies have demonstrated that a shift from a predominantly plant-based to a predominantly animal-based diet produces measurable changes in gut microbial composition within as little as five days. Antibiotic use has particularly disruptive effects, eliminating not only pathogenic bacteria but also beneficial commensal species, with some studies suggesting that certain antibiotic regimens can reduce microbial diversity by fifty per cent or more, with recovery taking weeks or months depending on the drug and the individual.

D.D Research into the gut-brain axis -- the bidirectional communication network linking the gut and the central nervous system -- has produced some of the most surprising findings in recent biomedical science. The gut produces approximately ninety per cent of the body's serotonin, a neurotransmitter conventionally associated with mood regulation in the brain. Germ-free mice -- animals raised in sterile conditions without any gut bacteria -- show abnormal stress responses and anxiety-like behaviour that can be reversed by colonising their guts with bacteria from normal mice. Human epidemiological studies have found associations between altered gut microbiome composition and conditions including depression, anxiety, and autism spectrum disorder, though establishing causality in human populations has proved considerably more difficult than in animal models.

E.E The possibility of manipulating the microbiome to treat disease has generated substantial commercial and scientific interest. Probiotic supplements, which introduce specific live bacterial strains, have a long history of popular use, though the evidence for their efficacy in most claimed applications remains limited. The most dramatic therapeutic application of microbiome manipulation is faecal microbiota transplantation (FMT), in which the gut microbiome of a patient is effectively replaced by that of a healthy donor through the transfer of processed stool samples. FMT has demonstrated high rates of efficacy in treating recurrent Clostridioides difficile infection -- a severe and difficult-to-treat bowel infection -- where it outperforms conventional antibiotic therapy. Applications to conditions ranging from inflammatory bowel disease to metabolic syndrome are under active investigation, though results to date have been more variable.

F.F The implications of the microbiome for our understanding of the boundary between self and non-self are philosophically interesting as well as medically significant. If the microorganisms inhabiting our bodies contribute to our mood, influence our food preferences, and train our immune systems, questions about the definition of individual biological identity become genuinely complex. Some researchers have proposed that the human organism is more usefully conceptualised as a superorganism -- an ecological community rather than a discrete individual. This framing, while provocative, risks obscuring the fact that the microbiome is not static but profoundly responsive to its host's behaviour and environment, making the relationship more dynamic partnership than merged identity. That is why clinicians increasingly describe microbiome health as part of systemic health rather than as a niche digestive issue, especially when inflammatory and neurological conditions are being investigated together.

True/False/Not Given

Questions 1-6

Do the following statements agree with the information given in the passage?

In boxes on your answer sheet, write:

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this in the passage

1. The ratio of microbial cells to human cells in the body was originally estimated to be much higher than current research suggests.

2. Gut bacteria are able to create vitamins that the human body is incapable of manufacturing on its own.

3. Babies born by caesarean section have been proven to develop more allergic conditions than those born naturally.

4. A diet change from plant-based to animal-based food produces changes in gut microbiome composition within one week.

5. Germ-free mice display abnormal behaviour that cannot be corrected once it has developed.

6. FMT has been shown to be more effective than antibiotic treatment for a specific bowel infection.

Matching Headings

Questions 7-11

The passage has paragraphs labelled A–F.

Choose the correct heading for each paragraph from the list below.

Write the correct number in the boxes on your answer sheet.

NB There are more headings than paragraphs, so you will not use all of them.

7. Paragraph B

8. Paragraph C

9. Paragraph D

10. Paragraph E

11. Paragraph F

Sentence Completion

Questions 12-13

Complete the sentences below.

Choose ONE WORD ONLY from the passage for each answer.

12. The gut microbiome lives primarily in the __________ tract.

13. After some antibiotic regimens, microbial diversity may take weeks or even __________ to recover.

Passage 2

The Philosophy Of Time: Does The Present Exist?

Why philosophers and physicists disagree about whether the present is real, how time acquires direction, and why the brain constructs temporal experience rather than simply receiving it.

A.A Time is perhaps the concept most fundamental to human experience and most resistant to philosophical analysis. Everyone knows what time is until asked to define it -- an observation attributed, perhaps apocryphally, to the philosopher Augustine of Hippo in the fourth century CE. The difficulty is not merely one of finding words for an obvious experience. It runs deeper: the very structure of time, and whether our intuitive sense of its passage reflects something real about the world, has been contested by philosophers and physicists for millennia.

B.B The most elementary division in the philosophy of time separates A-theory from B-theory. A-theorists hold that temporal becoming is objectively real: the past no longer exists, the future does not yet exist, and only the present is real. The flow of time -- the sense that events move from future through present into past -- reflects a genuine feature of the world rather than a property of the observer. B-theorists hold the opposite view: past, present, and future are equally real, and the apparent flow of time is an illusion generated by the perspective of the experiencing subject. On this view, the universe is a four-dimensional block in which all events exist simultaneously, and what we call the present is simply the location of an observer within that structure. The B-theory aligns more naturally with the picture of time that emerges from Einstein's special theory of relativity, in which the simultaneity of spatially separated events is not absolute but dependent on the observer's state of motion.

C.C A further puzzle concerns the asymmetry of time. We remember the past but not the future; effects follow causes but not vice versa; broken glass does not spontaneously reassemble. Yet the fundamental equations of classical physics and quantum mechanics are time-symmetric: they work equally well run forward or backward. The observable asymmetry of time -- what physicists call the arrow of time -- is typically explained by reference to entropy, the measure of disorder in a physical system. The second law of thermodynamics states that entropy in a closed system cannot decrease, which is why processes we observe in one temporal direction (ice melting, coffee cooling, populations ageing) do not reverse themselves. But this solution introduces a new puzzle: why was the entropy of the early universe so extraordinarily low, providing the headroom for it to increase ever since? This is the so-called past hypothesis, and its explanation remains genuinely open in cosmology.

D.D The experience of time's passage -- the sense that a distinct moment is happening now, and that this now is advancing -- is not obviously explained by either the physics or the metaphysics. Neuroscientists have documented that the sense of temporal order in experience is actively constructed by the brain rather than passively received. Signals arriving at the senses at slightly different times are integrated into a unified perceptual moment through a process called temporal binding, in which the brain groups events within a window of roughly eighty milliseconds into a single experienced instant. The psychological present is therefore not a mathematical point but a duration -- what the philosopher William James called the specious present -- whose extent varies with attention, arousal, and age.

E.E The relationship between the subjective experience of time and its objective description has been complicated further by findings in experimental psychology. Time appears to pass more slowly during frightening or high-arousal experiences -- an effect that has been attributed to the heightened encoding of memory rather than to any genuine slowing of neural processing. Conversely, time appears to accelerate as people age, an effect that several theories have attributed to the declining novelty of experience: when each year adds proportionally fewer genuinely new experiences to the total stock, its felt duration shrinks. This asymmetry between remembered time and anticipated time -- the fact that holidays seem longer in retrospect than in prospect -- remains one of the more curious features of temporal phenomenology.

F.F Whether the present moment has objective reality, whether time genuinely flows, and whether the direction of time is fundamental or merely statistical are questions that connect the most abstract reaches of physics and philosophy to the most immediate features of human experience. They are also questions that remain open, and on which intelligent and technically sophisticated people hold diametrically opposed views. This is not a sign of intellectual failure; it reflects the depth of the problem and the limits of the conceptual resources currently available for addressing it.

Yes/No/Not Given

Questions 14-19

Do the following statements agree with the claims of the writer?

In boxes on your answer sheet, write:

YES if the statement agrees with the claims of the writer

NO if the statement contradicts the claims of the writer

NOT GIVEN if it is impossible to say what the writer thinks about this

14. The difficulty of defining time was noted by a philosopher living before the Common Era.

15. B-theory is more consistent with Einstein's theory of relativity than A-theory is.

16. The second law of thermodynamics fully explains why the universe had low entropy at its beginning.

17. The brain processes incoming sensory signals into a single experienced moment lasting about eighty milliseconds.

18. The writer believes the apparent acceleration of time with age is caused by reduced brain processing speed.

19. The writer regards the unresolved nature of questions about time as evidence of a fundamental intellectual problem.

Sentence Completion

Questions 20-24

Complete the sentences below.

Choose NO MORE THAN TWO WORDS from the passage for each answer.

Write your answers in the boxes on your answer sheet.

20. A-theorists argue that the movement of events from future to present to past represents a genuine feature of the world rather than an attribute of the ______.

21. B-theory treats the universe as a structure with four dimensions in which all events ______.

22. The reason physical processes run in only one direction -- from order toward disorder -- is typically explained using the concept of ______.

23. The brain's grouping of events into a single moment is called ______.

24. William James described the psychological present as the ______, to distinguish it from an instantaneous mathematical point.

Passage 3

The Scramble For The Deep Sea

Why the international rush to mine the deep sea has intensified, and why the legal, ecological, and ethical disputes remain unresolved.

A.The deep seabed -- the ocean floor below two hundred metres and beyond the jurisdiction of any coastal state -- covers roughly half the surface of the Earth. For most of human history it was inaccessible, unknown, and of no economic consequence. This has changed. Advances in underwater robotics, sonar mapping, and mineral extraction technology have brought the deep seabed within reach of commercial exploitation, and the resource estimates that have emerged from exploratory surveys are extraordinary. Polymetallic nodules -- potato-shaped mineral concretions that have accumulated on certain abyssal plains over millions of years -- contain concentrations of manganese, nickel, cobalt, and copper that dwarf terrestrial reserves. Cobalt-rich crusts on seamounts contain vanadium and tellurium in concentrations not found elsewhere. Hydrothermal vent fields host massive sulphide deposits rich in copper, gold, silver, and zinc.

B.These resources have come to attention at a geopolitically significant moment. The clean energy transition is driving sharply higher demand for the battery metals -- cobalt, nickel, manganese, and lithium -- that polymetallic nodules contain in abundance. Electric vehicle manufacturers, battery producers, and technology companies have invested in or signed offtake agreements with deep-sea mining companies. Countries including China, South Korea, Japan, and several Pacific island nations have obtained exploration licences through the International Seabed Authority (ISA), the body established by the UN Convention on the Law of the Sea (UNCLOS) to regulate deep-sea mining in international waters. The ISA's mandate from UNCLOS is to act as a trustee for the common heritage of mankind -- a principle intended to ensure that the resources of the deep sea benefit all nations, including those without the technological capacity to exploit them directly.

C.The governance challenge is formidable. The ISA has been developing a mining code -- the regulatory framework governing commercial exploitation -- for over two decades, and its repeated delays have generated mounting frustration among contractors holding exploration licences. The situation was complicated dramatically in 2021 when the Pacific island nation of Nauru triggered a provision of UNCLOS known as the two-year rule, which required the ISA to finalise mining regulations by July 2023 or begin processing applications under existing frameworks regardless. This manoeuvre, widely seen as a pressure tactic on behalf of the mining company partly owned by Nauru, forced a confrontation between ISA member states over whether the regulatory framework was ready. When the deadline arrived, the ISA Council declined to approve a mining code, meaning applications can be submitted but not necessarily approved.

D.The scientific case for precaution is compelling and largely uncontested among marine biologists. Deep-sea ecosystems are among the most slowly recovering on Earth. The abyssal plains targeted for nodule mining are characterised by extremely low nutrient input and correspondingly low population densities of organisms, but remarkable species diversity -- significant proportions of sampled species at any given site have proved to be previously unknown to science. Experimental disturbances conducted at the DISCOL site in the Pacific in 1989, in which seabed sediment was deliberately ploughed, found that microbial community recovery was still incomplete when revisited twenty-six years later. Nodule formation occurs at rates of a few millimetres per million years, meaning that mined nodule fields would not recover on any humanly relevant timescale. The sediment plumes generated by nodule collection would disperse over areas vastly larger than the mining footprint itself, potentially affecting filter-feeding organisms across thousands of square kilometres.

E.Proponents of deep-sea mining dispute neither the existence of environmental risks nor the need for rigorous regulation, but argue that the calculus must account for the full environmental comparison. The alternative to marine cobalt and nickel is overwhelmingly terrestrial extraction in countries including the Democratic Republic of Congo and Indonesia, where mining operations are associated with severe human rights abuses, deforestation, and contamination of freshwater systems. Substitution effects in battery chemistry are possible but not yet commercially scalable at the speed the energy transition requires. On this view, the environmental cost of deep-sea mining must be weighed against the environmental and social costs of the alternatives, not against a counterfactual in which minerals are not extracted at all.

F.The legal landscape adds further complexity. UNCLOS defines the resources of the Area -- the collective term for the international seabed -- as the common heritage of mankind, but this concept has never been satisfactorily operationalised in the mining context. What proportion of revenues should accrue to the ISA for redistribution? Which states qualify for preferential benefit-sharing? How should the interests of sponsoring states -- which assume legal responsibility for their contractors' compliance -- be balanced against those of developing nations that have no sponsoring capacity? These questions embed deep disagreements about the meaning of equity in international resource governance that the negotiating history of UNCLOS left deliberately unresolved, and that the prospect of commercial mining has made suddenly urgent.

True/False/Not Given

Questions 25-29

Do the following statements agree with the information given in the passage?

In boxes on your answer sheet, write:

TRUE if the statement agrees with the information

FALSE if the statement contradicts the information

NOT GIVEN if there is no information on this in the passage

25. Polymetallic nodules on the ocean floor contain higher concentrations of certain metals than deposits found on land.

26. Nauru triggered the two-year rule in order to benefit a mining company in which it had a financial interest.

27. The ISA approved a mining code when the two-year deadline expired in 2023.

28. Scientists revisiting the DISCOL experimental site found that the ecosystem had fully recovered after twenty-six years.

29. Supporters of deep-sea mining argue that its environmental impact should be compared with the impact of alternative sources of the same minerals.

Matching Information

Questions 30-35

Which paragraph contains the following information?

Write the correct letter in the boxes on your answer sheet.

NB You may use any letter more than once.

NB Paragraphs are labelled A–F (paragraphs of Passage 3 in order).

30. A description of the legal body responsible for regulating deep-sea mining.

31. An argument that the ethical case for deep-sea mining depends on comparing it with its alternatives, not with an ideal.

32. Evidence that recovery from physical disturbance on the deep seabed is extremely slow.

33. A reference to unresolved questions about how profits from deep-sea mining should be shared.

34. An explanation of why demand for deep-sea minerals has recently increased.

35. A description of two different types of mineral deposit found on the deep seabed, in addition to polymetallic nodules.

Short-answer Questions

Questions 36-38

Answer the questions below.

Choose NO MORE THAN THREE WORDS from the passage for each answer.

Write your answers in the boxes on your answer sheet.

36. What name does the passage give to the legal principle that requires the deep sea to benefit all nations?

37. According to the passage, how slowly do polymetallic nodules form?

38. What term do scholars use to describe a situation in which one civilisation is inspired by the idea of a technology without copying its specific form?

Multiple Choice

Questions 39-40

Choose the correct letter, A, B, C or D.

39. Why does the passage say deep-sea minerals have become strategically attractive? A Because UNCLOS has prohibited land-based mining B Because the clean-energy transition is increasing demand for battery metals C Because nodule formation has accelerated in recent decades D Because most terrestrial cobalt reserves have already been exhausted

40. The unresolved issue of benefit-sharing is presented mainly as a question about: A sonar calibration standards B how to divide ecological monitoring costs C equity in international resource governance D whether sediment plumes can be modelled accurately