Reading 2026-01 Test 1

Mês do exame: 2026-01

Recriado a partir de relatos de candidatos — não é material oficial do IELTS. Áudios e textos são recriações para prática.

Reading Passage 1 - Dust and the American West

Images of deserts in the United States show dusty, barren landscapes, but the land may not always have been this way. Ever since settlers moved west across the US, there has been dust, clouds of it, everywhere. It was part of the landscape, or so it seemed to them. But there were no records of the landscape of the West until the settlers arrived. Now, evidence is starting to emerge which suggests that before the settlers, there was very little dust. The evidence comes from the San Juan Mountains of southwest Colorado, downwind of Arizona and New Mexico. There, Jason Neff, a geochemist from the University of Colorado, has been analyzing sediments, the sand, stones and mud, laid down over the past 5,000 years. Atmospheric dust was minimal throughout those five millennia until the mid-19th century, he says, but then, 'from about 1860 to 1900, dust deposition rates shot up.' This is surprising because usually dry means dusty, and the American West has almost always been dry, often drier than today. There was a near-permanent drought between 900 and 1300 which was so intense that it destroyed a series of Native American civilizations, including the Anasazi, whose cliff homes are now US national treasures. Yet the evidence from the San Juan lakes is that it was not dusty. Even as their civilization was collapsing, the Anasazi seem to have protected their soils from erosion. This was not the case with the European settlers once they brought their cows. The landscape the cattle were introduced to was remarkably ill-equipped to cope with grazing animals, says Neff. 'Unlike most other parts of the US, there were few grazers in the American Southwest until the Europeans came. No bison and few antelope or deer.' In the Great Plains to the east and north, bison roamed in vast herds. Their regular grazing had created tough grass, while the herds manured the soil. In the Southwest, the land had few defenses against a sudden invasion of millions of livestock, whose teeth stripped the grass and whose hooves punctured the hard crust of desert soils that protected them from the wind. The invasion was sudden, funded by a bubble of speculative investment, much of it from Britain. The money went into railroads and herds of cattle and sheep that rode the rails to the wide open pastures. By 1900, when sedimentation rates peaked, there were 20 million cattle and 25 million sheep in the West. One of the biggest ranches was owned by the Aztec Land and Cattle Company, which owned a million acres of land by 1884. Each acre had cost the company a mere 50 cents, and like many other speculators, it was only interested in quick profits and had little incentive to protect the soils from overgrazing. By the time Aztec sold the ranch in 1901, it was barren, with cattle carcasses scattered across the exhausted land. Such was the damage to the grasslands that even now few of the pastures have recovered. The parched and exposed soil simply blew away. The 1862 Homestead Act was passed in order to encourage the populating of the West. Any family willing to make the journey was entitled to claim 160 acres and farm it. Yet by the time people moved west in large numbers, the cattle companies had taken most of the land and surrounded it with barbed wire. The water sources were therefore cut off, and were aggressively guarded. It was only in the 1930s, with the passage of the Taylor Grazing Act, that federal authorities finally sought to limit cattle herds. Soil scientists have known for a while about the importance of the hard crust that forms on arid soils. 'These crusts can survive winds of up to a hundred miles an hour, but cattle hooves break the crust,' says Jayne Belnap, a soil ecologist at the US Geological Survey, Utah. The scale of the dust clouds created by the livestock invasion has until now been largely unknown. When Neff first discovered dust in Colorado lake sediments laid down in the 19th century, he was initially unsure where it came from. Maybe it had crossed the Pacific from China's Gobi Desert. But after investigating the size and chemical composition of the dust, Neff was clear that it mostly came from the American Southwest, mainly Arizona and New Mexico. Now, with the soil crusts gone, dust clouds still head north and are having significant ecological effects in the Colorado mountains. They carry nutrients with them into areas which previously evolved and survived without them. But perhaps the most dramatic impact of the dust has been on snowfields in the Rocky Mountain Range. Even a thin sprinkling of dark material means snow absorbs more solar radiation, meaning that snowmelt occurs far more rapidly during springtime. The impact on the ski tourism industry is obvious. The loss of snow and the shrinking of glaciers across the American West in the past century have been dramatic. Glacier National Park in Montana, for example, has lost three-quarters of its snow cover since 1910. All this is frequently attributed to global warming. While this almost certainly plays a role, Neff's findings suggest that dust may also contribute.

    Questions 1-7

    Do the following statements agree with the information given in Reading Passage 1? In boxes 1-7 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

    1. 1

      Jason Neff discovered there had been a dramatic rise in dust levels in the second half of the nineteenth century.

    2. 2

      The Anasazi civilization disappeared due to the impact of dust in the atmosphere.

    3. 3

      Before cattle were introduced to the American Southwest, large numbers of bison occupied the area.

    4. 4

      The bison population in the Great Plains diminished because European settlers found it easy to hunt them.

    5. 5

      The development of railroads across the US was more expensive than originally expected.

    6. 6

      The Aztec Land and Cattle Company worked hard to take care of the grazing land it owned.

    7. 7

      Most of the land once owned by the Aztec Land and Cattle Company remains infertile today.

    Questions 8-13: Note completion

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

    American Southwest: 1860s to present day 1862 - Homestead Act was passed to encourage settlement in the West. 1930s - Laws were passed to control the size of 8 _________. Today Jayne Belnap believes: soil was not affected by high 9 _________ soil was seriously affected by cattle hooves. Jason Neff: found that 10 _________ in the Colorado region contained dust examined the dust for its chemical content as well as its 11 _________ concluded that the dust was from the American Southwest found that dust affects mountain environments by bringing in 12 _________ that are not normally found there, causing faster seasonal snowmelt argues that dust is partly to blame for the gradual disappearance of some 13 _________ and snow.
    1. 8

      1930s - Laws were passed to control the size of 8 _________.

    2. 9

      soil was not affected by high 9 _________

    3. 10

      found that 10 _________ in the Colorado region contained dust

    4. 11

      examined the dust for its chemical content as well as its 11 _________

    5. 12

      found that dust affects mountain environments by bringing in 12 _________ that are not normally found there, causing faster seasonal snowmelt

    6. 13

      argues that dust is partly to blame for the gradual disappearance of some 13 _________ and snow.

    Reading Passage 2 - Extinction of Aussie Animals

    World Wildlife Fund Australia has revealed its list of extinct wildlife to coincide with Australia Day. The list covers a wide range of species, from birds to reptiles, marsupials, insects and even flowers. Top of the list is the green and gold frog which has had its home decimated by drought. Many Aussie species need our help in order to survive, WWF threatened species program manager Kat Miller said. Without knowing the reason many had disappeared for, we will risk losing another 346 animal and 1249 plant species listed as threatened under federal legislation. Australia has one of the worst records of mammal extinction in the world. WWF Australia said 9 percent of birds, 7 percent of reptiles and 16 percent of amphibians are extinct since early human settlement. The conservation group said half the mammals that have become extinct globally in the last 200 years have been Australian species. Ancient hunters and gatherers may have triggered the failure of the annual Australian Monsoon some 12,000 years ago by burning massive tracts of the country's interior, resulting in the desertification that is evident today, says a new study. Researcher Gifford Miller of the University of Colorado at Boulder said the new study builds on his research group's previous findings that dozens of giant animal species became extinct in Australia 50,000 years ago due to ecosystem changes caused by human burning. This study, appearing in Geology, indicates such burning may have altered the flora enough to decrease the exchange of water vapor between the biosphere and atmosphere, causing the failure of the Australian Monsoon over the interior. The question is whether localized burning 50,000 years ago could have had a continental-scale effect, said Miller. The implications are that the burning practices of early humans may have changed the climate of the Australian continent by weakening the penetration of monsoon moisture into the interior. A paper on the subject by Miller appears in the January issue of Geology. Co-authors include CU Boulder's Jennifer Mangan, David Pollard, Starley Thompson and Benjamin Felzer of the National Center for Atmospheric Research in Boulder and John Magee of Australian National University in Canberra. Geologic evidence indicates the interior of Australia was much wetter about 125,000 years ago during the last interglacial period. Although planetary and meteorological conditions during the most recent ice age caused Earth's major monsoons to waver, all except the Australian Monsoon were reinvigorated to full force during the Holocene Period beginning about 12,000 years ago, he said. Although the Australian Monsoon delivers about 39 inches of rain annually to the north coast as it moves south from Asia, only about 13 inches of rain now falls on the continent's interior each year, said Miller. Lake Eyre, a deep-water lake in the continent's interior that was filled by regular monsoon rains about 60,000 years ago, is now a huge salt flat that is occasionally covered by a thin layer of salty water. The earliest human colonizers are believed to have arrived in Australia by sea from Indonesia about 50,000 years ago, using fire as a tool to hunt, clear paths, signal each other and promote the growth of certain plants, he said. Fossil remains of browse-dependent birds and marsupials indicate the interior was made up of trees, shrubs and grasses rather than the desert scrub environment present today. The researchers used global climate model simulations to evaluate the atmospheric and meteorological conditions in Australia over time, as well as the sensitivity of the monsoon to different vegetation and soil types. A climate model simulating a forested Australia produced twice as much annual monsoon precipitation over the continental interior as the model simulating arid scrub conditions, he said. Systematic burning across the semiarid zone, where nutrients are the lowest of any continental region, may have been responsible for the rapid transformation of a drought-tolerant ecosystem high in broad-leaf species to the modern desert scrub, he said. In the process, vegetation feedbacks promoting the penetration of monsoon moisture into the continental interior would have been disrupted. More than 85 percent of Australia's mega fauna weighing more than 100 pounds went extinct roughly 50,000 years ago, including an ostrich-sized bird, 19 species of marsupials, a 25-foot-long lizard and a Volkswagen-sized tortoise, he said. Evidence for burning includes increased charcoal deposits preserved in lake sediments at the boundary between rainforest and interior desert beginning about 50,000 years ago, Miller said. In addition, a number of rainforest gymnosperms - plants whose seeds are not encased and protected and are therefore more vulnerable to fire - went extinct at about that time. Natural fires resulting from summer lightning strikes have played an integral part in the ecology of Australia's interior, and many plant species are adapted to regimes of frequent fires, he said. But the systematic burning of the interior by the earliest colonizers differed enough from the natural fire cycle that key ecosystems may have been pushed past a threshold from which they could not recover.

      Questions 14-16: Matching headings

      Reading Passage 2 contains 8 paragraphs A-H. Which paragraphs state the following information? Write the appropriate letters A-H in boxes 14-16 on your answer sheet.

      1. 14

        Why did an interior Australian lake change to a dry flat?

      2. 15

        When did an ostrich-sized bird go extinct?

      3. 16

        Why did the ancient settlers in Australia burn the forests?

      Questions 17-20: Sentence completion (matching from box)

      Choose ONE phrase from the list of phrases A-G below to complete each of the sentences 17-20 below. Write the appropriate letters (A-G) in boxes 17-20 on your answer sheet.

      A. caused the failure of the annual Australian Monsoon by burning tracts. B. were responsible for the distinction of an Australian giant animal species because of their massive hunting. C. showed that in the past the interior of Australia was not a desert. D. altered the flora to decrease the exchange of water vapor between the biosphere and atmosphere. E. suggested that the changed climate of the Australian continent was led by the weakened penetration of monsoon moisture into the interior. F. indicated that the forests facilitated more rainfall. G. indicated that the extinction of an Australian species resulted from changes in the local ecosystem.
      1. 17

        Ancient hunters and gatherers

      2. 18

        January issue of Geology

      3. 19

        Fossil remains

      4. 20

        A climate model

      Questions 21-26

      Do the following statements agree with the claims of the writer in Reading Passage 2? On your answer sheet please write TRUE if the statement is true FALSE if the statement is false NOT GIVEN if the information is not given in the passage.

      1. 21

        According to the WWF, Australia has the worst record of animal extinction in the world.

      2. 22

        In Australia, hundreds of endangered animals and plants species will keep disappearing.

      3. 23

        The distinction of Australian giant animals was a knock-on effect after human burning ceased the monsoon.

      4. 24

        Lake Eyre has always been filled with salty water.

      5. 25

        It is a theoretic assumption that early humans burned massive tracts in Australia.

      6. 26

        Varieties of plants from Australia's interior have now adapted to recurrent fires.

      Reading Passage 3 - Gravity

      Without forces of gravitation, Earth and other planets would be unable to stay in their orbits around the Sun. the Moon would be unable to orbit the Earth, tidal waves would not occur and the rising of hot air or water convection would be impossible. Gravitation is a phenomenon which allows objects to attract other matter; the physics behind it has been explained in The Theory of Relativity and Newton's Law of Universal Gravitation; though attempts to explain gravity hail back to ancient times. In 4th Century BC, the Greek philosopher Aristotle developed the hypothesis that all objects were drawn into their correct position by crystalline spheres and that a physical mass would fall towards the earth in direct proportion to its weight. In the late 16th century Galileo deduced that while gravitation propels all objects to the ground at the same rate, air resistance resulted in heavier objects appearing to fall more quickly; his theories contradicting earlier belief systems put in place by Aristotle and others; so paving the way for the formulation of the modern theories of today. Though the two terms are now used interchangeably in layman use, strictly by scientific definition, there are distinct differences between 'gravitation' and 'gravity'. The first relates to the influence exerted by different objects which allow them to attract other objects, whereas 'gravity' refers specifically to the force possessed by such objects which facilitates gravitation. Certain scientific theories hold that gravitation may be initiated by a combination of factors and not simply the existence of gravity alone; though doubts have been raised regarding some of these theories. Gravity is directly proportional to mass; a smaller object possessing less gravity. To illustrate, the Moon is a quarter of the Earth's size and possesses only 1/6 of its gravity. The mass of the Earth itself is not spread out proportionally, being flatter at the poles than the equator as a result of its rotation; gravity and gravitational pull in different locations throughout the world also vary. In the 1960s, as a result of research into the worldwide gravity fields, it was discovered that inexplicably areas around and including the Hudson Bay area of Canada appeared to possess significantly lower levels of gravity than other parts of the globe; the reasons for this dissimilarity have since been extensively investigated resulting in two explanations. The original theory presented attributed this anomaly to the activity which occurs 100-200 kilometres below the Earth's surface within the layer known as the 'mantle'. The mantle is comprised of hot molten rock known as magma which flows under the earth's surface causing convection currents. These convection currents can result in the lowering of the continental plates which make up the Earth's surface, as a result when this occurs, the mass in that area and its gravity is also reduced. Research findings indicated that such activity had occurred in the Hudson Bay region. More recently a second conjecture suggested that, in fact, lower levels of gravity in the area are a result of occurrences during the Ice Age. The Laurentide ice sheet, which covered most of Canada and the northern tip of the USA until it melted 10,000 years ago, is thought to have been 3.2 km thick in most parts and 3.7 km thick over two areas of Hudson Bay. The sheer weight of the ice layer weighed down the surface of the earth below, leaving a deep indentation once it had melted, having caused the area around Hudson Bay to become thinner as the earth's surface was pushed to the edges of the ice sheet. Extensive investigation has since been carried out by the Harvard-Smithsonian Center for Astrophysics using data collected by satellites during the Gravity Recovery and Climate Experiment (GRACE) between 2002 and 2006. The satellites are placed 220kms apart and orbit 500kms above Earth. Being extremely sensitive to even minor differences in the gravitational pull of the areas of earth they pass over, as the first satellite enters an area with decreased gravity it moves slightly away from the earth as the gravitational pull is reduced and also moves slightly further away from the sister satellite that follows, such activity allowing scientists to create maps of gravitational fields. The GRACE findings also allowed scientists to estimate the appearance of Hudson Bay over 10,000 years ago, prior to the great thaw. The areas possessing the lowest gravity today correlate with the areas covered in the thickest layers of ice at that time. Researchers now believe that both theories regarding reduced gravity levels in the Hudson Bay region are accurate and that the area's characteristics are a result of both magma activity and the impact of the Laurentide ice-sheet. It has been estimated that the former has resulted in 55-75% of gravity reduction and that pressure resulting from the latter accounts for 25-45%. The effects of the Laurentide ice-sheet are reversible due to the earth layer's capability to 'rebound' in response to the removal of the weight which once restricted it. Return to the original position, however, is an extremely slow process; it is estimated that the area around Hudson Bay will take a further 5,000 years to recover the altitude it once possessed prior to the Laurentide ice-sheet. The rebound activity in the area is also measurable through observation of sea levels; unlike the rest of the world, sea levels are not rising in the area as a result of melting icecaps, but are dropping as the land recovers its previous form. Research conducted into the Laurentide ice-sheet has significant implications on a global scale. The increased knowledge of how that particular area has changed over time and the long-term implications activity in the Ice Age had, pave the way to a better understanding of how current changes elsewhere will manifest themselves over the long term.

        Questions 27-32: Heading matching

        Reading Passage 3 has nine paragraphs A-I. Choose the correct heading for paragraphs B, C and E-H from the list of headings below. Write the correct number i-x in boxes 27-32 on your answer sheet.

        List of Headings I. Return to previous form II. Substantiating a hypothesis III. Historic theories IV. The general rule of gravity and an exception V. The initial explanation VI. How proximity to the poles affected Hudson Bay VII. Scientific definition and contemporary views VIII. Relevance to our future IX. An alternative viewpoint X. Consolidating theories
        1. 27

          Paragraph B

        2. 28

          Paragraph C

        3. 29

          Paragraph E

        4. 30

          Paragraph F

        5. 31

          Paragraph G

        6. 32

          Paragraph H

        Questions 33-37

        Do the following statements agree with the information given in Reading Passage 3? In boxes 33-37 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

        1. 33

          Differentiation between gravity and gravitational pull is generally only made by academics in the field.

        2. 34

          Gravity levels in areas around the equator are significantly higher than around the poles.

        3. 35

          It was first believed that lower gravity levels in Hudson Bay could be attributed to its location between the poles and the equator.

        4. 36

          Molten rock activity within the magma layer has had less of an impact on gravity levels in the Hudson Bay area than the Laurentide ice-sheet.

        5. 37

          The GRACE project's main focus was areas of Canada and North America once thought to be covered by the Laurentide ice-sheet.

        Questions 38-40: Sentence completion (matching from box)

        Complete the sentences below with words from the box below. Write the correct letter A-J in boxes 38-40 on your answer sheet.

        A. crystalline spheres B. mass C. 3.2kms D. continental plates E. gravity fields F. warming G. 3.5kms H. mantle layers I. convection currents J. air resistance
        1. 38

          The impact of ……………… on objects falling to the ground was not considered by Aristotle.

        2. 39

          Investigations of …………….. first led to the discovery of the unusual levels in Hudson Bay.

        3. 40

          The earth's surface has been observed to sink as a direct result of ………………

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        1. 1. TRUE

          This is correct because Neff found that 'from about 1860 to 1900, dust deposition rates shot up,' showing a dramatic rise in dust levels in the second half of the nineteenth century.

        2. 2. FALSE

          This is false because the passage says the Anasazi civilization was destroyed by drought, not dust: 'There was a near-permanent drought... so intense that it destroyed a series of Native American civilizations, including the Anasazi.'

        3. 3. FALSE

          This is false because the passage says 'there were few grazers in the American Southwest until the Europeans came. No bison and few antelope or deer,' so large numbers of bison did not occupy the area before cattle.

        4. 4. NOT GIVEN

          Not given because the passage only mentions bison in the Great Plains and does not say why their population diminished or if settlers found it easy to hunt them.

        5. 5. NOT GIVEN

          Not given because the passage mentions investment in railroads but does not discuss whether the development was more expensive than expected.

        6. 6. FALSE

          This is false because the passage says the Aztec Land and Cattle Company 'was only interested in quick profits and had little incentive to protect the soils from overgrazing.'

        7. 7. TRUE

          This is true because the passage says, 'Such was the damage to the grasslands that even now few of the pastures have recovered. The parched and exposed soil simply blew away.'

        8. 8. cattle herds

          The answer is 'cattle herds' because the passage says, 'it was only in the 1930s, with the passage of the Taylor Grazing Act, that federal authorities finally sought to limit cattle herds.'

        9. 9. winds

          The answer is 'winds' because the passage says, 'These crusts can survive winds of up to a hundred miles an hour, but cattle hooves break the crust,' showing soil was not affected by high winds.

        10. 10. lake sediments

          The answer is 'lake sediments' because Neff 'discovered dust in Colorado lake sediments laid down in the 19th century.'

        11. 11. size

          The answer is 'size' because Neff investigated 'the size and chemical composition of the dust.'

        12. 12. nutrients

          The answer is 'nutrients' because the passage says dust clouds 'carry nutrients with them into areas which previously evolved and survived without them.'

        13. 13. glaciers

          The answer is 'glaciers' because the passage says, 'the loss of snow and the shrinking of glaciers across the American West... have been dramatic,' and Neff's findings suggest dust may contribute.

        14. 14. D

          D is correct because the passage says Lake Eyre 'was filled by regular monsoon rains about 60,000 years ago, is now a huge salt flat,' showing the change was due to less rain from the monsoon.

        15. 15. G

          G is correct because the passage says, 'More than 85 percent of Australia's mega fauna weighing more than 100 pounds went extinct roughly 50,000 years ago, including an ostrich-sized bird.'

        16. 16. E

          E is correct because the passage says early humans used fire 'to hunt, clear paths, signal each other and promote the growth of certain plants.'

        17. 17. A

          A is correct because the passage says, 'Ancient hunters and gatherers may have triggered the failure of the annual Australian Monsoon some 12,000 years ago by burning massive tracts.'

        18. 18. E

          E is correct because the passage says, 'A paper on the subject by Miller appears in the January issue of Geology.'

        19. 19. C

          C is correct because the passage says, 'Fossil remains of browse-dependent birds and marsupials indicate the interior was made up of trees, shrubs and grasses.'

        20. 20. F

          F is correct because the passage says, 'A climate model simulating a forested Australia produced twice as much annual monsoon precipitation... as the model simulating arid scrub conditions.'

        21. 21. NOT GIVEN

          Not given because the passage says Australia has 'one of the worst records of mammal extinction,' but does not say it is the worst in the world.

        22. 22. NOT GIVEN

          Not given because the passage says many species are threatened, but does not state that hundreds will definitely keep disappearing.

        23. 23. TRUE

          True because the passage says, 'dozens of giant animal species became extinct in Australia 50,000 years ago due to ecosystem changes caused by human burning,' which led to monsoon failure.

        24. 24. FALSE

          False because the passage says Lake Eyre 'was filled by regular monsoon rains about 60,000 years ago, is now a huge salt flat,' so it has not always been filled with salty water.

        25. 25. FALSE

          False because the passage presents evidence for burning, such as 'increased charcoal deposits preserved in lake sediments,' so it is not just a theoretical assumption.

        26. 26. TRUE

          True because the passage says, 'many plant species are adapted to regimes of frequent fires,' showing adaptation to recurrent fires.

        27. 27. vii

          vii is correct because Paragraph B discusses 'Aristotle's theory' about objects falling, matching heading vii.

        28. 28. iv

          iv is correct because Paragraph C explains 'Galileo's experiments,' matching heading iv.

        29. 29. ix

          ix is correct because Paragraph E discusses 'theories about the Hudson Bay anomaly,' matching heading ix.

        30. 30. ii

          ii is correct because Paragraph F describes 'the Laurentide ice-sheet,' matching heading ii.

        31. 31. x

          x is correct because Paragraph G discusses 'the GRACE project,' matching heading x.

        32. 32. i

          i is correct because Paragraph H discusses 'the global significance' of the research, matching heading i.

        33. 33. TRUE

          True because the passage says, 'Though the two terms are now used interchangeably in layman use, strictly by scientific definition, there are distinct differences,' showing only academics make the distinction.

        34. 34. NOT GIVEN

          Not given because the passage says gravity varies by location but does not state that gravity is significantly higher at the equator than at the poles.

        35. 35. FALSE

          False because the passage says the original theory for low gravity in Hudson Bay was due to mantle activity, not its location between poles and equator.

        36. 36. FALSE

          False because the passage says magma activity accounts for '55-75%' of gravity reduction, which is more than the '25-45%' from the ice-sheet, so magma has had more impact.

        37. 37. NOT GIVEN

          Not given because the passage describes the GRACE project's methods but does not say its main focus was areas once covered by the Laurentide ice-sheet.

        38. 38. J

          J is correct because the passage says Aristotle believed objects fell in direct proportion to their weight, but Galileo showed air resistance affects falling objects, which Aristotle did not consider.

        39. 39. E

          E is correct because the passage says, 'In the 1960s, as a result of research into the worldwide gravity fields, it was discovered that... Hudson Bay... possessed significantly lower levels of gravity,' so investigations of gravity fields led to the discovery.

        40. 40. I

          I is correct because the passage says, 'These convection currents can result in the lowering of the continental plates which make up the Earth's surface,' so the earth's surface sinks due to convection currents.

        Reading 2026-01 Test 1 — IELTS Reading Actual Test with Answers | IELTS Actual Tests