Sinh học biển là một trong những lĩnh vực khoa học hấp dẫn nhất, với vô số bí ẩn chờ được khám phá dưới đại dương sâu thẳm. Chủ đề “Discoveries In Marine Biology” xuất hiện với tần suất khá cao trong kỳ thi IELTS Reading, đặc biệt ở Passage 2 và Passage 3, đòi hỏi khả năng đọc hiểu các bài viết khoa học với từ vựng học thuật phong phú.
Trong bài viết này, bạn sẽ nhận được một đề thi IELTS Reading hoàn chỉnh với 3 passages được thiết kế theo đúng chuẩn Cambridge, tăng dần về độ khó từ Easy đến Hard. Đề thi bao gồm đa dạng các dạng câu hỏi phổ biến như Multiple Choice, True/False/Not Given, Matching Headings, Summary Completion và nhiều dạng khác. Mỗi câu hỏi đều có đáp án chi tiết kèm giải thích cụ thể về vị trí thông tin, cách paraphrase và chiến lược làm bài.
Ngoài ra, bạn còn được trang bị bộ từ vựng quan trọng liên quan đến sinh học biển, các collocations hữu ích và những tips thực chiến từ kinh nghiệm 20 năm giảng dạy. Đề thi này phù hợp cho học viên từ band 5.0 trở lên, giúp bạn làm quen với format thi thật và nâng cao kỹ năng đọc hiểu một cách toàn diện.
Hướng Dẫn Làm Bài IELTS Reading
Tổng Quan Về IELTS Reading Test
IELTS Reading Test kéo dài 60 phút với 3 passages và tổng cộng 40 câu hỏi. Mỗi câu trả lời đúng được tính 1 điểm, không bị trừ điểm khi sai. Đề thi được thiết kế với độ khó tăng dần, trong đó Passage 1 thường dễ nhất và Passage 3 khó nhất.
Phân bổ thời gian khuyến nghị:
- Passage 1: 15-17 phút (13 câu hỏi)
- Passage 2: 18-20 phút (13 câu hỏi)
- Passage 3: 23-25 phút (14 câu hỏi)
Lưu ý rằng bạn cần tự quản lý thời gian và chuyển đáp án vào Answer Sheet trong 60 phút này. Không có thời gian bổ sung để chuyển đáp án như phần Listening.
Các Dạng Câu Hỏi Trong Đề Này
Đề thi mẫu về Discoveries in Marine Biology bao gồm 7 dạng câu hỏi phổ biến nhất:
- Multiple Choice – Chọn đáp án đúng nhất trong 3-4 phương án
- True/False/Not Given – Xác định thông tin đúng, sai hay không được đề cập
- Matching Information – Ghép thông tin với đoạn văn tương ứng
- Matching Headings – Chọn tiêu đề phù hợp cho từng đoạn
- Summary Completion – Điền từ vào chỗ trống trong đoạn tóm tắt
- Matching Features – Ghép đặc điểm với đối tượng tương ứng
- Short-answer Questions – Trả lời câu hỏi ngắn theo yêu cầu
IELTS Reading Practice Test
PASSAGE 1 – Coral Reefs: The Rainforests of the Ocean
Độ khó: Easy (Band 5.0-6.5)
Thời gian đề xuất: 15-17 phút
Coral reefs are among the most biologically diverse ecosystems on Earth, often referred to as the “rainforests of the sea.” These underwater structures are built by tiny marine animals called coral polyps, which secrete calcium carbonate to form hard, protective skeletons. Over thousands of years, these skeletons accumulate to create the massive reef structures we see today. Despite covering less than 0.1% of the ocean floor, coral reefs support approximately 25% of all marine species, making them crucial habitats for ocean life.
The formation of coral reefs is a slow and delicate process. Coral polyps have a symbiotic relationship with microscopic algae called zooxanthellae, which live within their tissues. These algae perform photosynthesis, converting sunlight into energy that nourishes the coral. In return, the coral provides the algae with protection and access to sunlight. This partnership is so important that without it, most reef-building corals would not survive. The vibrant colors we associate with coral reefs actually come from these algae, not from the coral polyps themselves.
Coral reefs can be found in tropical and subtropical waters around the world, but they require specific conditions to thrive. They need warm water temperatures, typically between 23-29 degrees Celsius, and cannot survive in water colder than 18 degrees. Clear, shallow water is essential because the zooxanthellae need sunlight to photosynthesize. Most reef-building corals are found in waters less than 50 meters deep. Additionally, coral reefs need relatively low nutrient levels; too many nutrients can cause algae blooms that block sunlight and suffocate the coral.
There are three main types of coral reefs: fringing reefs, barrier reefs, and atolls. Fringing reefs grow directly from the shore and are the most common type. They form a narrow strip along the coastline, sometimes with a shallow channel or lagoon between the reef and the shore. Barrier reefs are larger structures that run parallel to the coast but are separated from it by a deeper, wider lagoon. The Great Barrier Reef in Australia, the world’s largest coral reef system, is a prime example of this type. Atolls are ring-shaped reefs that form around volcanic islands. As the island slowly sinks over millions of years, the coral continues to grow upward, eventually forming a circular reef surrounding a central lagoon.
The ecological importance of coral reefs extends far beyond their immediate environment. They serve as nursery grounds for many fish species, providing shelter and food for juvenile fish before they move to deeper waters. This makes reefs essential for maintaining healthy fish populations, which in turn supports the fishing industry that millions of people depend on. Coral reefs also protect coastlines from erosion by absorbing wave energy during storms and hurricanes. Without these natural barriers, coastal communities would face significantly more damage from tropical storms.
However, coral reefs face unprecedented threats in the modern era. Climate change is causing ocean temperatures to rise, leading to a phenomenon called coral bleaching. When water becomes too warm, corals expel their zooxanthellae, losing their color and their primary food source. If conditions don’t improve quickly, the coral will die. Ocean acidification, caused by increased carbon dioxide absorption, makes it harder for corals to build their calcium carbonate skeletons. Other threats include overfishing, which disrupts the reef ecosystem’s balance, pollution from agricultural runoff and coastal development, and physical damage from careless tourism and destructive fishing practices.
Scientists estimate that if current trends continue, up to 90% of coral reefs could be severely degraded by 2050. This has prompted urgent conservation efforts worldwide. Many countries have established marine protected areas where fishing and development are restricted or prohibited. Some scientists are developing coral restoration techniques, including growing coral fragments in nurseries and transplanting them to damaged reefs. Others are researching ways to breed heat-resistant coral strains that might survive warmer ocean temperatures. Community education programs are teaching coastal residents and tourists about the importance of reef conservation and how their actions can help or harm these fragile ecosystems.
Recent studies have revealed that coral reefs may be more resilient than previously thought. Some reefs show the ability to recover from bleaching events if given enough time and if other stressors are reduced. This discovery has given marine biologists hope that with proper protection and management, coral reefs might survive the challenges ahead. However, experts agree that reducing greenhouse gas emissions and addressing climate change remain the most critical actions needed to ensure the long-term survival of coral reefs.
Questions 1-13
Questions 1-5: Multiple Choice
Choose the correct letter, A, B, C or D.
1. According to the passage, coral reefs are called “rainforests of the sea” because
A. they have similar climate requirements
B. they support a high diversity of species
C. they are found in tropical regions
D. they grow in dense formations
2. The vibrant colors of coral reefs come from
A. the coral polyps themselves
B. calcium carbonate deposits
C. zooxanthellae algae
D. various fish species
3. Coral reefs require clear, shallow water primarily because
A. deep water is too cold for coral survival
B. zooxanthellae need sunlight for photosynthesis
C. coral polyps cannot build skeletons in deep water
D. nutrients are more abundant in shallow areas
4. Which type of coral reef forms when a volcanic island sinks?
A. Fringing reefs
B. Barrier reefs
C. Atolls
D. Coastal reefs
5. The main reason coral reefs are important for coastal protection is that they
A. provide fish for local communities
B. absorb wave energy during storms
C. prevent ocean acidification
D. maintain water temperature
Questions 6-9: True/False/Not Given
Do the following statements agree with the information in the passage?
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
6. Coral polyps can survive indefinitely without zooxanthellae.
7. Barrier reefs are separated from the coastline by a lagoon.
8. The Great Barrier Reef is the oldest coral reef system in the world.
9. Coral reefs provide shelter for juvenile fish species.
Questions 10-13: Summary Completion
Complete the summary below. Choose NO MORE THAN TWO WORDS from the passage for each answer.
Coral reefs face numerous threats in modern times. Rising ocean temperatures cause 10. __, a process where corals expel their zooxanthellae and may die. Additionally, 11. __ makes it difficult for corals to build their protective skeletons. Human activities such as 12. __ disrupt the ecosystem balance, while pollution from agriculture and development damages reef health. Conservation efforts include establishing 13. __ and developing techniques to restore damaged reefs.
Rạn san hô nhiệt đới đầy màu sắc với các loài cá biển và sinh vật biển đa dạng, thể hiện hệ sinh thái phong phú dưới đại dương
PASSAGE 2 – Bioluminescence: Nature’s Living Light Show
Độ khó: Medium (Band 6.0-7.5)
Thời gian đề xuất: 18-20 phút
One of the most mesmerizing phenomena in marine biology is bioluminescence – the ability of living organisms to produce and emit light. This remarkable biochemical process occurs when a light-emitting molecule called luciferin reacts with oxygen in the presence of an enzyme called luciferase, releasing energy in the form of light. Unlike the light produced by incandescent bulbs, which wastes much energy as heat, bioluminescent light is considered “cold light” because nearly 100% of the energy is released as light rather than heat, making it one of the most efficient forms of light production known to science.
Bioluminescence has evolved independently at least 40 times across various marine species, suggesting that it provides significant evolutionary advantages. In the ocean’s depths, where sunlight cannot penetrate, approximately 76% of organisms have developed the ability to produce their own light. This includes fish, squid, jellyfish, crustaceans, and even single-celled organisms. The widespread occurrence of bioluminescence in marine environments, compared to terrestrial ecosystems where it is relatively rare, is attributed to the unique challenges and opportunities presented by the ocean’s darkness.
Marine organisms have developed bioluminescence for several crucial survival functions. One of the most common uses is counter-illumination camouflage, a technique employed by fish and squid living in the ocean’s twilight zone – the region between 200 and 1,000 meters deep. During daytime, when some sunlight still filters down from above, predators looking up from below can spot prey as dark silhouettes against the lighter water. To counter this, many species have light-producing organs called photophores on their undersides that match the intensity and color of the light coming from above, effectively making them invisible to predators below. Some species, like the Hawaiian bobtail squid, house bioluminescent bacteria in specialized light organs and can adjust the brightness of their glow by controlling the flow of oxygen to these bacteria.
Communication represents another vital function of bioluminescence. The ostracod crustaceans of the Caribbean, tiny shrimp-like creatures, use bioluminescent displays as part of their mating rituals. Males swim upward in the water column while releasing glowing mucus in specific patterns unique to their species, creating luminous trails that females can recognize from a distance. Similarly, certain species of deep-sea anglerfish use bioluminescent lures to attract mates in the vast darkness where finding a partner would otherwise be nearly impossible. The patterns, frequencies, and colors of these light displays serve as a species-specific language that prevents interbreeding between different species.
Perhaps the most fascinating application of bioluminescence is for hunting and defense. The anglerfish dangles a bioluminescent lure above its mouth, attracting curious prey close enough to be captured in its powerful jaws. In contrast, the stoplight loosejaw fish has evolved a unique hunting strategy: it produces red bioluminescence, which most deep-sea creatures cannot see because they lack the appropriate photoreceptors. This allows the loosejaw to illuminate potential prey without alerting them to danger, essentially creating its own private “night vision” system. For defense, many species employ bioluminescent burglar alarms – when attacked, they release clouds of glowing chemicals that confuse predators or attract even larger predators to the scene, allowing the prey to escape in the chaos.
The dinoflagellates, microscopic single-celled organisms, create one of the most spectacular bioluminescent displays in nature. These organisms are responsible for the glowing blue waves sometimes seen along tropical coastlines at night. When disturbed by waves or movement in the water, millions of dinoflagellates simultaneously emit brief flashes of blue light, creating an ethereal glow across the ocean surface. Scientists believe this defensive mechanism startles small predators and makes them visible to larger predators, providing protection for the dinoflagellates. However, under certain environmental conditions, dinoflagellates can multiply rapidly, creating harmful algal blooms known as “red tides,” which can be toxic to marine life and humans.
Research into marine bioluminescence has led to groundbreaking applications in medical and scientific fields. The discovery and isolation of green fluorescent protein (GFP) from the bioluminescent jellyfish Aequorea victoria revolutionized biological research. Scientists now use GFP as a biological marker to track cellular processes, gene expression, and the spread of diseases like cancer. This discovery was so significant that the scientists responsible were awarded the 2008 Nobel Prize in Chemistry. More recently, researchers have developed bioluminescent biosensors that can detect pollution, bacteria, and chemical contamination by glowing when they encounter specific substances, offering a fast and cost-effective alternative to traditional testing methods.
Marine biologists continue to discover new bioluminescent species and mechanisms. In 2020, researchers identified bioluminescence in a species of pygmy shark that was previously unknown to have this capability. They found that these sharks have thousands of tiny photophores covering their bodies, suggesting a complex counter-illumination camouflage system. Deep-sea exploration using advanced submersibles and remotely operated vehicles has revealed entire ecosystems illuminated by bioluminescent organisms. These discoveries have challenged previous assumptions about deep-sea life and demonstrated that the ocean’s darkest regions are far from lifeless.
Understanding bioluminescence also provides insights into the broader impacts of human activity on marine ecosystems. Light pollution from coastal development can disrupt the natural light signals that marine organisms use for communication and survival. Similarly, ocean warming and acidification may affect the chemical processes that enable bioluminescence, though research in this area is still developing. As we continue to explore the ocean’s depths and unravel the mysteries of bioluminescence, we gain not only scientific knowledge but also a deeper appreciation for the remarkable adaptations that life has developed to thrive in Earth’s most challenging environments.
Questions 14-26
Questions 14-18: Yes/No/Not Given
Do the following statements agree with the views of the writer in the passage?
Write:
- YES if the statement agrees with the views of the writer
- NO if the statement contradicts the views of the writer
- NOT GIVEN if it is impossible to say what the writer thinks about this
14. Bioluminescent light is more efficient than artificial lighting because it produces minimal heat.
15. Bioluminescence evolved only once and then spread to different marine species.
16. Counter-illumination camouflage is most effective in the ocean’s deepest regions.
17. The red bioluminescence produced by the stoplight loosejaw gives it an advantage when hunting.
18. All dinoflagellate blooms are harmful to marine ecosystems.
Questions 19-23: Matching Information
Match each statement with the correct organism (A-F). You may use any letter more than once.
A. Hawaiian bobtail squid
B. Ostracod crustaceans
C. Anglerfish
D. Stoplight loosejaw fish
E. Dinoflagellates
F. Pygmy shark
19. Uses patterns of light as part of mating behavior
20. Can control the brightness of its bioluminescence by regulating oxygen flow
21. Produces light that most deep-sea creatures cannot detect
22. Has thousands of light-producing organs across its body
23. Creates glowing displays that can be seen from beaches
Questions 24-26: Summary Completion
Complete the summary below. Choose NO MORE THAN THREE WORDS from the passage for each answer.
The discovery of 24. __ from bioluminescent jellyfish has had major impacts on biological research, earning scientists a Nobel Prize. This protein now serves as a 25. __ to observe cellular activities and disease progression. Additionally, scientists have created 26. __ that glow when they detect specific pollutants or bacteria, providing an efficient method for environmental monitoring.
Các sinh vật biển phát sáng sinh học tự nhiên trong môi trường nước sâu tối tăm, thể hiện hiện tượng bioluminescence độc đáo
PASSAGE 3 – The Microbiome of the Ocean: Invisible Architects of Marine Ecosystems
Độ khó: Hard (Band 7.0-9.0)
Thời gian đề xuất: 23-25 phút
The ocean’s most influential inhabitants are not the charismatic megafauna that capture public imagination – whales, sharks, or dolphins – but rather the microscopic organisms that constitute the marine microbiome. This vast, largely invisible world comprises bacteria, archaea, viruses, and protists that collectively orchestrate fundamental biogeochemical processes essential for planetary health. Recent advances in genomic sequencing technologies and computational biology have revolutionized our understanding of these microbial communities, revealing complex ecological networks whose metabolic activities regulate everything from nutrient cycling to climate patterns. The recognition that microorganisms represent approximately 98% of ocean biomass and are responsible for roughly half of global photosynthesis underscores their paramount importance in marine biology and Earth system science.
Prochlorococcus, a genus of cyanobacteria discovered only in 1988, exemplifies how recent marine microbiology is as a discipline. Despite being among the smallest photosynthetic organisms known, measuring merely 0.6 micrometers in diameter, Prochlorococcus is also the most abundant: an estimated 3 octillion (3 × 10²⁷) cells exist globally. These organisms inhabit the euphotic zone – the upper 200 meters of ocean where sufficient light penetrates for photosynthesis – and collectively produce approximately 10% of global oxygen. What makes Prochlorococcus particularly fascinating is its extraordinary genetic diversity; different strains have adapted to specific light conditions, with “high-light ecotypes” thriving near the surface and “low-light ecotypes” dominating deeper waters. This ecological stratification demonstrates how even morphologically similar microorganisms can occupy distinct ecological niches, maximizing the efficiency of primary production across varying environmental gradients.
The viral component of the marine microbiome, known as the virioplankton, represents another frontier in marine biology that has only recently begun to receive appropriate scientific attention. Viruses in the ocean, primarily bacteriophages that infect bacteria, exist at concentrations of approximately 10 million per milliliter of seawater – roughly ten times more abundant than bacterial cells. These viruses play a crucial role in what scientists call the “viral shunt,” a process whereby viral lysis (the breaking open) of bacterial cells releases dissolved organic matter back into the water column rather than allowing it to move up the food chain to larger organisms. This mechanism has profound implications for carbon cycling: it retains carbon in surface waters longer, affecting the ocean’s role as a carbon sink. Furthermore, viruses facilitate horizontal gene transfer between bacteria, driving genetic diversity and potentially accelerating microbial adaptation to changing environmental conditions. Some researchers propose that viruses should be considered not merely pathogens but integral components of ecosystem functioning, acting as genetic reservoirs and evolutionary catalysts.
The discovery of chemosynthetic ecosystems around hydrothermal vents fundamentally challenged previous assumptions about the energy sources necessary for life. Before the late 1970s, scientists believed that all complex ecosystems ultimately depended on photosynthesis. However, the identification of chemosynthetic bacteria capable of deriving energy from the oxidation of hydrogen sulfide and other chemicals emanating from vents demonstrated that chemical energy could support entire food webs in the absolute absence of sunlight. These bacteria form symbiotic relationships with vent fauna, including the famous giant tube worms (Riftia pachyptila), which have no digestive system but instead house chemosynthetic bacteria in specialized organs called trophosome. This discovery not only expanded our understanding of possible energy sources for life but also influenced astrobiology, suggesting that life might exist in extreme environments on other planets or moons, such as Europa or Enceladus, where similar chemical energy sources might be available.
Marine microbiomes exhibit remarkable functional redundancy and metabolic versatility, characteristics that contribute to ecosystem resilience but also complicate our efforts to predict responses to environmental change. The concept of functional redundancy suggests that multiple species can perform similar ecological functions, such that the loss of one species may not immediately impact ecosystem processes if others can compensate. However, this apparent redundancy may be deceptive; while many marine bacteria can degrade organic matter, specific groups may be uniquely adapted to process particular compounds or function optimally under certain conditions. Research using metagenomics – the study of genetic material recovered directly from environmental samples – has revealed that microbial communities maintain vast reserves of genetic potential that may only be expressed under specific environmental triggers. This “rare biosphere” of low-abundance taxa can rapidly proliferate when conditions favor their particular metabolic capabilities, providing ecosystems with a dynamic adaptive capacity.
The nitrogen cycle represents a particularly instructive case study in microbial marine ecology. Nitrogen, essential for protein and nucleic acid synthesis, exists in multiple forms in the ocean, and specialized bacterial groups mediate transformations between these forms. Nitrogen fixation, the conversion of atmospheric nitrogen (N₂) into biologically available ammonia, is performed by diazotrophic bacteria such as Trichodesmium, which provides nitrogen to nutrient-poor tropical waters, effectively fertilizing vast oceanic regions. Conversely, other bacterial groups perform denitrification, converting nitrate back to nitrogen gas, which returns to the atmosphere. The balance between these processes influences ocean productivity and affects atmospheric composition. Recent discoveries of novel nitrogen cycle participants, including anammox bacteria that convert ammonia and nitrite directly to nitrogen gas in oxygen-minimum zones, have forced revisions to nitrogen cycle models and highlighted how much remains to be discovered about marine microbial ecology.
Anthropogenic impacts on marine microbiomes constitute an emerging research priority with potentially far-reaching consequences. Ocean warming affects microbial metabolism rates and community composition, with implications for biogeochemical cycling rates. Ocean acidification may favor certain microbial groups over others, potentially altering competitive dynamics and ecosystem functions. Pollution introduces novel compounds that can disrupt microbial communities or, conversely, select for bacteria capable of degrading anthropogenic chemicals, such as oil-degrading bacteria that proliferate following spills. The introduction of plastic debris into marine environments has created entirely new ecological niches, with distinct microbial communities colonizing plastic surfaces in what researchers call the “plastisphere.” These communities may facilitate plastic degradation but could also harbor pathogenic species or assist plastic transport across ocean basins, with unpredictable ecological consequences.
The methodological revolution in marine microbiology, driven by high-throughput sequencing and bioinformatics, has generated unprecedented volumes of data while simultaneously creating new challenges. Traditional cultivation-based approaches could characterize only approximately 1% of marine microorganisms, as most resist laboratory culture under standard conditions. Modern culture-independent techniques have revealed extraordinary diversity, but they also generate complexity that strains analytical capacities. The Tara Oceans expedition (2009-2013), which sampled marine microbiomes globally, generated petabytes of data that scientists continue to analyze. This research has identified millions of previously unknown genes and thousands of potential new species, but translating these discoveries into mechanistic understanding of ecosystem functioning requires integrating multiple data types and developing sophisticated computational models.
Looking forward, marine microbiome research faces both tremendous opportunities and significant challenges. Understanding how these invisible communities respond to and influence global change processes remains imperative for predicting ocean futures. Some researchers propose microbiome-based management strategies, such as using microbial indicators to assess ecosystem health or deliberately manipulating microbial communities to enhance desired ecosystem services. However, such interventions raise ecological and ethical questions about unintended consequences and our right to modify natural systems. As our knowledge of marine microbiomes deepens, so too does our appreciation for their complexity and our humility regarding how much remains unknown. These microscopic organisms, invisible to the naked eye but omnipresent in their influence, remind us that the ocean’s most important discoveries often come from studying its smallest inhabitants.
Questions 27-40
Questions 27-31: Multiple Choice
Choose the correct letter, A, B, C or D.
27. According to the passage, Prochlorococcus is significant because
A. it was discovered recently and is very large
B. it is extremely abundant and produces substantial oxygen
C. it lives deeper than any other photosynthetic organism
D. it has no genetic diversity across different strains
28. The “viral shunt” described in the passage
A. moves carbon quickly up the food chain
B. eliminates all bacteria from surface waters
C. keeps carbon in surface waters longer
D. prevents all horizontal gene transfer
29. The discovery of chemosynthetic ecosystems at hydrothermal vents
A. confirmed that all life requires photosynthesis
B. showed that chemical energy can support complex ecosystems
C. proved that life cannot exist without sunlight
D. demonstrated that bacteria cannot form symbiotic relationships
30. Functional redundancy in marine microbiomes means that
A. all bacterial species perform identical functions
B. losing one species always causes ecosystem collapse
C. multiple species can perform similar ecological roles
D. rare species never become important
31. The “plastisphere” refers to
A. plastic pollution in ocean gyres
B. bacteria that can digest all types of plastic
C. microbial communities living on plastic debris
D. a new method for studying marine microbes
Questions 32-36: Matching Features
Match each research finding or concept (Questions 32-36) with the correct organism or phenomenon (A-H). You may use any letter more than once.
A. Prochlorococcus
B. Bacteriophages
C. Chemosynthetic bacteria
D. Giant tube worms
E. Trichodesmium
F. Anammox bacteria
G. Plastisphere communities
H. Tara Oceans data
32. Contains different strains adapted to varying light levels
33. Provides nitrogen fertilization to tropical ocean waters
34. Houses symbiotic bacteria in a specialized organ
35. Converts ammonia and nitrite directly to nitrogen gas
36. Generated enormous amounts of data requiring ongoing analysis
Questions 37-40: Short-answer Questions
Answer the questions below. Choose NO MORE THAN THREE WORDS AND/OR A NUMBER from the passage for each answer.
37. What percentage of ocean biomass do microorganisms represent?
38. What are the viruses that primarily infect bacteria called?
39. What term describes the ocean zone where Prochlorococcus lives and where light is sufficient for photosynthesis?
40. What technology has allowed scientists to study marine microorganisms that cannot be grown in laboratories?
Vi sinh vật biển đa dạng nhìn qua kính hiển vi điện tử cho thấy cấu trúc phức tạp và vai trò trong hệ sinh thái đại dương
Answer Keys – Đáp Án
PASSAGE 1: Questions 1-13
- B
- C
- B
- C
- B
- FALSE
- TRUE
- NOT GIVEN
- TRUE
- coral bleaching
- ocean acidification
- overfishing
- marine protected areas
PASSAGE 2: Questions 14-26
- YES
- NO
- NO
- YES
- NOT GIVEN
- B
- A
- D
- F
- E
- green fluorescent protein / GFP
- biological marker
- bioluminescent biosensors
PASSAGE 3: Questions 27-40
- B
- C
- B
- C
- C
- A
- E
- D
- F
- H
- 98% / approximately 98%
- bacteriophages
- euphotic zone
- culture-independent techniques
Giải Thích Đáp Án Chi Tiết
Passage 1 – Giải Thích
Câu 1: B
- Dạng câu hỏi: Multiple Choice
- Từ khóa: rainforests of the sea, why
- Vị trí trong bài: Đoạn 1, dòng 1-4
- Giải thích: Passage nói rõ “Despite covering less than 0.1% of the ocean floor, coral reefs support approximately 25% of all marine species” – tức là san hô chiếm diện tích nhỏ nhưng nuôi sống rất nhiều loài sinh vật. Đây là lý do được gọi là “rainforests of the sea”. Đáp án B “they support a high diversity of species” paraphrase ý này chính xác nhất.
Câu 2: C
- Dạng câu hỏi: Multiple Choice
- Từ khóa: vibrant colors, come from
- Vị trí trong bài: Đoạn 2, dòng cuối
- Giải thích: “The vibrant colors we associate with coral reefs actually come from these algae, not from the coral polyps themselves.” Câu này nói trực tiếp màu sắc đến từ tảo zooxanthellae chứ không phải từ san hô.
Câu 3: B
- Dạng câu hỏi: Multiple Choice
- Từ khóa: clear, shallow water, primarily because
- Vị trí trong bài: Đoạn 3, dòng 3-4
- Giải thích: “Clear, shallow water is essential because the zooxanthellae need sunlight to photosynthesize.” Đây là lý do chính được nêu rõ ràng trong passage.
Câu 6: FALSE
- Dạng câu hỏi: True/False/Not Given
- Từ khóa: coral polyps, survive, without zooxanthellae
- Vị trí trong bài: Đoạn 2, dòng 5-6
- Giải thích: “This partnership is so important that without it, most reef-building corals would not survive” – rõ ràng san hô không thể sống lâu dài mà không có tảo, nên câu “can survive indefinitely” là sai.
Câu 7: TRUE
- Dạng câu hỏi: True/False/Not Given
- Từ khóa: barrier reefs, separated, lagoon
- Vị trí trong bài: Đoạn 4, dòng 3-4
- Giải thích: “Barrier reefs are larger structures that run parallel to the coast but are separated from it by a deeper, wider lagoon.” Khớp chính xác với thông tin trong câu hỏi.
Câu 10: coral bleaching
- Dạng câu hỏi: Summary Completion
- Từ khóa: rising ocean temperatures cause
- Vị trí trong bài: Đoạn 6, dòng 2-3
- Giải thích: “Climate change is causing ocean temperatures to rise, leading to a phenomenon called coral bleaching.” Đây là hiện tượng được mô tả khi nước nóng lên.
Câu 11: ocean acidification
- Dạng câu hỏi: Summary Completion
- Từ khóa: makes it difficult, build skeletons
- Vị trí trong bài: Đoạn 6, dòng 5-6
- Giải thích: “Ocean acidification, caused by increased carbon dioxide absorption, makes it harder for corals to build their calcium carbonate skeletons.”
Passage 2 – Giải Thích
Câu 14: YES
- Dạng câu hỏi: Yes/No/Not Given
- Từ khóa: bioluminescent light, more efficient, minimal heat
- Vị trí trong bài: Đoạn 1, dòng 4-6
- Giải thích: Passage nói “nearly 100% of the energy is released as light rather than heat, making it one of the most efficient forms of light production” – điều này khẳng định quan điểm trong câu hỏi.
Câu 15: NO
- Dạng câu hỏi: Yes/No/Not Given
- Từ khóa: evolved only once, spread
- Vị trí trong bài: Đoạn 2, dòng 1-2
- Giải thích: “Bioluminescence has evolved independently at least 40 times” – trái ngược hoàn toàn với “evolved only once”, nên đáp án là NO.
Câu 16: NO
- Dạng câu hỏi: Yes/No/Not Given
- Từ khóa: counter-illumination camouflage, most effective, deepest regions
- Vị trí trong bài: Đoạn 3, dòng 1-3
- Giải thích: Counter-illumination được mô tả là hiệu quả ở “twilight zone – the region between 200 and 1,000 meters deep”, không phải ở vùng sâu nhất (deepest regions), nên câu này mâu thuẫn với thông tin.
Câu 19: B
- Dạng câu hỏi: Matching Information
- Từ khóa: patterns of light, mating behavior
- Vị trí trong bài: Đoạn 4, dòng 2-4
- Giải thích: “The ostracod crustaceans… Males swim upward in the water column while releasing glowing mucus in specific patterns… as part of their mating rituals.”
Câu 24: green fluorescent protein / GFP
- Dạng câu hỏi: Summary Completion
- Từ khóa: discovery, jellyfish, Nobel Prize
- Vị trí trong bài: Đoạn 7, dòng 2-3
- Giải thích: “The discovery and isolation of green fluorescent protein (GFP) from the bioluminescent jellyfish… This discovery was so significant that the scientists responsible were awarded the 2008 Nobel Prize in Chemistry.”
Passage 3 – Giải Thích
Câu 27: B
- Dạng câu hỏi: Multiple Choice
- Từ khóa: Prochlorococcus, significant
- Vị trí trong bài: Đoạn 2, dòng 2-4
- Giải thích: “Prochlorococcus is also the most abundant: an estimated 3 octillion cells exist globally” và “collectively produce approximately 10% of global oxygen” – đáp án B tóm tắt chính xác hai đặc điểm quan trọng này.
Câu 28: C
- Dạng câu hỏi: Multiple Choice
- Từ khóa: viral shunt
- Vị trí trong bài: Đoạn 3, dòng 4-7
- Giải thích: “This mechanism has profound implications for carbon cycling: it retains carbon in surface waters longer” – đáp án C paraphrase ý này chính xác.
Câu 32: A
- Dạng câu hỏi: Matching Features
- Từ khóa: different strains, varying light levels
- Vị trí trong bài: Đoạn 2, dòng 5-7
- Giải thích: “What makes Prochlorococcus particularly fascinating is its extraordinary genetic diversity; different strains have adapted to specific light conditions, with ‘high-light ecotypes’ thriving near the surface and ‘low-light ecotypes’ dominating deeper waters.”
Câu 37: 98% / approximately 98%
- Dạng câu hỏi: Short-answer Question
- Từ khóa: percentage, ocean biomass, microorganisms
- Vị trí trong bài: Đoạn 1, dòng 5-6
- Giải thích: “The recognition that microorganisms represent approximately 98% of ocean biomass” – đây là con số cụ thể được đề cập.
Câu 39: euphotic zone
- Dạng câu hỏi: Short-answer Question
- Từ khóa: zone, Prochlorococcus, light, photosynthesis
- Vị trí trong bài: Đoạn 2, dòng 4-5
- Giải thích: “These organisms inhabit the euphotic zone – the upper 200 meters of ocean where sufficient light penetrates for photosynthesis.”
Từ Vựng Quan Trọng Theo Passage
Passage 1 – Essential Vocabulary
| Từ vựng | Loại từ | Phiên âm | Nghĩa tiếng Việt | Ví dụ từ bài | Collocation |
|---|---|---|---|---|---|
| biologically diverse | adj phrase | /ˌbaɪəˈlɒdʒɪkli daɪˈvɜːs/ | đa dạng sinh học | biologically diverse ecosystems | highly/extremely biologically diverse |
| coral polyps | n | /ˈkɒrəl ˈpɒlɪps/ | polyp san hô | tiny marine animals called coral polyps | coral polyps secrete/build |
| accumulate | v | /əˈkjuːmjəleɪt/ | tích tụ, tích lũy | these skeletons accumulate | accumulate over time/years |
| symbiotic relationship | n phrase | /ˌsɪmbaɪˈɒtɪk rɪˈleɪʃnʃɪp/ | quan hệ cộng sinh | have a symbiotic relationship | form/establish a symbiotic relationship |
| zooxanthellae | n | /ˌzəʊəzænˈθeli/ | tảo zooxanthellae | microscopic algae called zooxanthellae | harbor/contain zooxanthellae |
| nursery grounds | n phrase | /ˈnɜːsəri ɡraʊndz/ | nơi ương nuôi | serve as nursery grounds | important/critical nursery grounds |
| coral bleaching | n phrase | /ˈkɒrəl ˈbliːtʃɪŋ/ | sự tẩy trắng san hô | a phenomenon called coral bleaching | cause/prevent coral bleaching |
| ocean acidification | n phrase | /ˈəʊʃn əˌsɪdɪfɪˈkeɪʃn/ | sự axit hóa đại dương | Ocean acidification makes it harder | combat/address ocean acidification |
| conservation efforts | n phrase | /ˌkɒnsəˈveɪʃn ˈefəts/ | nỗ lực bảo tồn | prompted urgent conservation efforts | support/strengthen conservation efforts |
| marine protected areas | n phrase | /məˈriːn prəˈtektɪd ˈeəriəz/ | khu bảo tồn biển | established marine protected areas | create/designate marine protected areas |
| resilient | adj | /rɪˈzɪliənt/ | có khả năng phục hồi | reefs may be more resilient | remarkably/surprisingly resilient |
| degraded | adj | /dɪˈɡreɪdɪd/ | bị suy thoái | could be severely degraded | heavily/severely degraded |
Passage 2 – Essential Vocabulary
| Từ vựng | Loại từ | Phiên âm | Nghĩa tiếng Việt | Ví dụ từ bài | Collocation |
|---|---|---|---|---|---|
| mesmerizing | adj | /ˈmezməraɪzɪŋ/ | mê hoặc, quyến rũ | most mesmerizing phenomena | absolutely/utterly mesmerizing |
| bioluminescence | n | /ˌbaɪəʊˌluːmɪˈnesns/ | phát quang sinh học | the ability of living organisms to produce bioluminescence | produce/emit bioluminescence |
| biochemical process | n phrase | /ˌbaɪəʊˈkemɪkl ˈprəʊses/ | quá trình sinh hóa | this remarkable biochemical process | complex/intricate biochemical process |
| luciferin | n | /luːˈsɪfərɪn/ | luciferin (chất phát quang) | a light-emitting molecule called luciferin | luciferin reacts with oxygen |
| evolved independently | v phrase | /ɪˈvɒlvd ˌɪndɪˈpendəntli/ | tiến hóa độc lập | has evolved independently | evolved independently multiple times |
| counter-illumination | n | /ˌkaʊntər ɪˌluːmɪˈneɪʃn/ | chiếu sáng ngược | counter-illumination camouflage | use/employ counter-illumination |
| photophores | n | /ˈfəʊtəfɔːz/ | cơ quan phát sáng | light-producing organs called photophores | specialized/bioluminescent photophores |
| ostracod crustaceans | n phrase | /ˈɒstrəkɒd krʌˈsteɪʃnz/ | giáp xác ostracod | The ostracod crustaceans use displays | marine/tiny ostracod crustaceans |
| species-specific | adj | /ˈspiːʃiːz spəˈsɪfɪk/ | đặc trùng loài | serve as a species-specific language | unique/highly species-specific |
| dinoflagellates | n | /ˌdaɪnəʊˈflædʒəleɪts/ | tảo hai roi | The dinoflagellates create displays | marine/bioluminescent dinoflagellates |
| ethereal glow | n phrase | /ɪˈθɪəriəl ɡləʊ/ | ánh sáng huyền ảo | creating an ethereal glow | emit/produce an ethereal glow |
| green fluorescent protein | n phrase | /ɡriːn ˌflʊəˈresnt ˈprəʊtiːn/ | protein huỳnh quang xanh | discovery of green fluorescent protein (GFP) | isolate/express green fluorescent protein |
| biological marker | n phrase | /ˌbaɪəˈlɒdʒɪkl ˈmɑːkə/ | dấu ấn sinh học | use GFP as a biological marker | serve as/act as a biological marker |
| biosensors | n | /ˌbaɪəʊˈsensəz/ | cảm biến sinh học | developed bioluminescent biosensors | create/develop biosensors |
| deep-sea exploration | n phrase | /diːp siː ˌekspləˈreɪʃn/ | khảo sát biển sâu | Deep-sea exploration using submersibles | conduct/undertake deep-sea exploration |
Passage 3 – Essential Vocabulary
| Từ vựng | Loại từ | Phiên âm | Nghĩa tiếng Việt | Ví dụ từ bài | Collocation |
|---|---|---|---|---|---|
| charismatic megafauna | n phrase | /ˌkærɪzˈmætɪk ˌmeɡəˈfɔːnə/ | động vật lớn hấp dẫn | not the charismatic megafauna | protect/conserve charismatic megafauna |
| microbiome | n | /ˈmaɪkrəʊbaɪəʊm/ | hệ vi sinh vật | the marine microbiome comprises | diverse/complex microbiome |
| archaea | n | /ɑːˈkiːə/ | vi khuẩn cổ | bacteria, archaea, viruses | ancient/marine archaea |
| genomic sequencing | n phrase | /dʒiˈnəʊmɪk ˈsiːkwənsɪŋ/ | giải trình tự gen | advances in genomic sequencing | high-throughput genomic sequencing |
| metabolic activities | n phrase | /ˌmetəˈbɒlɪk ækˈtɪvətiz/ | hoạt động trao đổi chất | whose metabolic activities regulate | diverse/complex metabolic activities |
| paramount importance | n phrase | /ˈpærəmaʊnt ɪmˈpɔːtns/ | tầm quan trọng tối cao | underscores their paramount importance | of paramount importance |
| cyanobacteria | n | /ˌsaɪənəʊbækˈtɪəriə/ | vi khuẩn lam | a genus of cyanobacteria | photosynthetic/marine cyanobacteria |
| euphotic zone | n phrase | /juːˈfəʊtɪk zəʊn/ | tầng ưu quang | inhabit the euphotic zone | upper/productive euphotic zone |
| ecological niches | n phrase | /ˌiːkəˈlɒdʒɪkl ˈniːtʃɪz/ | ô sinh thái | occupy distinct ecological niches | fill/exploit ecological niches |
| bacteriophages | n | /bækˈtɪəriəfeɪdʒɪz/ | thực khuẩn thể | primarily bacteriophages that infect | marine/specific bacteriophages |
| viral lysis | n phrase | /ˈvaɪrəl ˈlaɪsɪs/ | sự phân giải do virus | viral lysis of bacterial cells | undergo/cause viral lysis |
| horizontal gene transfer | n phrase | /ˌhɒrɪˈzɒntl dʒiːn ˈtrænsfɜː/ | chuyển gen ngang | facilitate horizontal gene transfer | enable/mediate horizontal gene transfer |
| chemosynthetic | adj | /ˌkeməʊsɪnˈθetɪk/ | hóa tổng hợp | chemosynthetic ecosystems | unique/specialized chemosynthetic |
| hydrothermal vents | n phrase | /ˌhaɪdrəʊˈθɜːml vents/ | miệng phun thủy nhiệt | around hydrothermal vents | deep-sea/active hydrothermal vents |
| symbiotic relationships | n phrase | /ˌsɪmbaɪˈɒtɪk rɪˈleɪʃnʃɪps/ | quan hệ cộng sinh | form symbiotic relationships | establish/maintain symbiotic relationships |
| functional redundancy | n phrase | /ˈfʌŋkʃənl rɪˈdʌndənsi/ | sự dự phòng chức năng | exhibit remarkable functional redundancy | high/significant functional redundancy |
| metagenomics | n | /ˌmetəˈdʒiːnɒmɪks/ | metagenomics | research using metagenomics | apply/employ metagenomics |
| diazotrophic bacteria | n phrase | /daɪˌæzəʊˈtrɒfɪk bækˈtɪəriə/ | vi khuẩn cố định đạm | performed by diazotrophic bacteria | nitrogen-fixing diazotrophic bacteria |
| anthropogenic impacts | n phrase | /ˌænθrəpəˈdʒenɪk ˈɪmpækts/ | tác động nhân tạo | Anthropogenic impacts on microbiomes | reduce/minimize anthropogenic impacts |
| plastisphere | n | /ˈplæstɪsfɪə/ | vùng sinh thái nhựa | in what researchers call the plastisphere | colonize/inhabit the plastisphere |
Kết Bài
Chủ đề “Discoveries in marine biology” không chỉ thường xuyên xuất hiện trong IELTS Reading mà còn mang đến những bài đọc vô cùng hấp dẫn về thế giới đại dương bí ẩn. Qua ba passages với độ khó tăng dần từ Easy đến Hard, bạn đã được trải nghiệm một đề thi hoàn chỉnh với 40 câu hỏi đa dạng, từ Multiple Choice, True/False/Not Given, Matching Information, đến Summary Completion và Short-answer Questions.
Passage 1 giới thiệu về rạn san hô với từ vựng cơ bản và cấu trúc câu dễ hiểu, phù hợp cho band 5.0-6.5. Passage 2 đưa bạn vào thế giới bioluminescence với các khái niệm phức tạp hơn và yêu cầu kỹ năng paraphrase tốt, phù hợp cho band 6.0-7.5. Passage 3 về marine microbiome thách thức khả năng đọc hiểu học thuật của bạn với từ vựng chuyên ngành và cấu trúc câu phức tạp, phù hợp cho band 7.0-9.0.
Phần đáp án chi tiết đã chỉ ra vị trí cụ thể của thông tin trong từng passage, giải thích cách paraphrase giữa câu hỏi và đoạn văn, giúp bạn hiểu rõ tại sao một đáp án đúng và phát triển kỹ năng làm bài bài bản. Bộ từ vựng được tổng hợp theo từng passage với phiên âm, nghĩa tiếng Việt, ví dụ và collocations sẽ là tài liệu quý giá cho quá trình học từ vựng của bạn.
Hãy luyện tập thường xuyên với các đề thi mẫu như thế này, chú ý quản lý thời gian và áp dụng các chiến lược đọc hiểu đã học. Với sự chuẩn bị kỹ lưỡng và luyện tập đúng cách, bạn hoàn toàn có thể đạt được band điểm mong muốn trong kỳ thi IELTS Reading. Chúc bạn ôn tập hiệu quả và thành công!
