IELTS Reading Practice: The Deep Sea (Answers & Detailed Analysis)

While we are busy gazing at the stars and dreaming of Mars, a far more mysterious and vast world remains largely unexplored right here on Earth: the deep ocean. The IELTS reading passage “The Deep Sea” serves as a sobering reminder of how much we still don’t know about our own planet, while recounting the arduous journey of humanity’s attempts to conquer this “final frontier.”

The following article from ECE English provides a translation, in-depth vocabulary analysis, and a thorough explanation of each question to help you master this reading passage.

Reading Passage

The Deep Sea

A. At a time when most think of outer space as the final frontier, we must remember that a great deal of unfinished business remains here on Earth. Robots crawl on the surface of Mars, and spacecraft exit our solar system, but most of our planet has still never been seen by human eyes. It seems ironic that we know more about impact craters on the far side of the moon than about the longest and largest mountain range on Earth. It is incredible that human beings crossed a quarter of a million miles of space to visit our nearest celestial neighbour before penetrating just two miles deep into the Earth’s own waters to explore the Midocean Ridge. And it would be hard to imagine a more significant part of our planet to investigate – a chain of volcanic mountains 42,000 miles long where most of the Earth’s solid surface was born, and where vast volcanoes continue to create new submarine landscapes.

B. The figure we so often see quoted—71% of the Earth’s surface—understates the oceans’ importance. If you consider three-dimensional volumes instead, the land dwellers’ share of the planet shrinks even more toward insignificance: less than 1% of the total. Most of the oceans’ enormous volume lies deep below the familiar surface. The upper sunlit layer, by one estimate, contains only 2 or 3% of the total space available to life. The other 97% of the Earth’s biosphere lies deep beneath the water’s surface, where sunlight never penetrates. Until recently, it was impossible to study the deep ocean directly. By the sixteenth century, diving bells allowed people to stay underwater for a short time: they could swim to the bell to breathe air trapped underneath it rather than return to the surface. Later, other devices, including pressurized or armoured suits, heavy metal helmets, and compressed air supplied through hoses from the surface, allowed at least one diver to reach 500 feet or so. It was 1930 when a biologist named William Beebe and his engineering colleague Otis Barton sealed themselves into a new kind of diving craft, an invention that finally allowed humans to penetrate beyond the shallow sunlit layer of the sea, and the history of deep-sea exploration began. Science then was largely incidental – something that happened along the way. In terms of technical ingenuity and human bravery, this part of the story is every bit as amazing as the history of early aviation. Yet many of these individuals, and the deep-diving vehicles that they built and tested, are not well known.

C. It was not until the 1970s that deep-diving manned submersibles were able to reach the Midocean Ridge and begin making major contributions to a wide range of scientific questions. A burst of discoveries followed in short order. Several of these profoundly changed the whole field of science and their implications are still not fully understood. For example, biologists may now be seeing – in the strange communities of microbes and animals that live around deep volcanic vents – clues to the origin of life on Earth. No one even knew that these communities existed before explorers began diving to the bottom in a submersible. Entering the deep, black abyss presents unique challenges for which humans must carefully prepare if they wish to survive. It is an unforgiving environment, both harsh and strangely beautiful, that few who have not experienced it firsthand can fully appreciate. Even the most powerful searchlights penetrate only tens of feet. Suspended particles scatter the light and water itself is less transparent than air; it absorbs and scatters light. The ocean also swallows other types of electromagnetic radiation, including radio signals. That is why many deep-sea vehicles dangle from tethers. Inside those tethers, copper wires or fibre optic strands transmit signals that would dissipate and die if broadcast into open water.

D. Another challenge is that the temperature near the bottom in very deep water typically hovers just four degrees above freezing, and submersibles rarely have much insulation. Since water absorbs heat more quickly than air, the cold down below seems to penetrate a diving capsule far more quickly than it would penetrate, say, a control van up above, on the deck of the mother ship. And finally, the abyss clamps down with crushing pressure on anything that enters it. This force is like air pressure on land, except that water is much heavier than air. At sea level on land, we don’t even notice the atmosphere of pressure, about 15 pounds per square inch, the weight of the Earth’s blanket of air. In the deepest part of the ocean, nearly seven miles down, it’s about 1,200 atmospheres, 18,000 pounds per square inch. A square-inch column of lead would crush down on your body with equal force if it were 3,600 feet tall.

E. Fish that live in the deep don’t feel the pressure, because they are filled with water from their environment. It has already been compressed by abyssal pressure as much as water can be (which is not much). A diving craft, however, is a hollow chamber, rudely displacing the water around it. That chamber must withstand the full brunt of deep-sea pressure – thousands of pounds per square inch. If seawater with that much pressure behind it ever finds a way to break inside, it explodes through the hole with laser-like intensity. It was into such a terrifying environment that the first twentieth-century explorers ventured.

Questions 27 – 30 (Multiple Choice)

Write the correct letter, A, B, C, or D, in boxes 27 – 30 on your answer sheet.

27. In the first paragraph, the writer finds it surprising that …

A. we send robots to Mars rather than to the sea bed.

B. we choose to explore the least accessible side of the moon.

C. people reached the moon before they explored the deepest parts of the Earth’s oceans.

D. spaceships are sent beyond our solar system instead of exploring it.

28. The writer argues that saying 71% of the Earth’s surface is the ocean is not accurate because it …………………

A. ignores the depth of the world’s oceans.

B. is based on an estimated volume.

C. overlooks the significance of landscape features.

D. refers to the proportion of water in which life is possible.

29. How did the diving bell help divers?

A. It allowed each diver to carry a supply of air underwater.

B. It enabled piped air to reach deep below the surface.

C. It offered access to a reservoir of air below the surface.

D. It meant that they could dive as deep as 500 feet.

30. What point does the writer make about scientific discoveries between 1930 and 1970?

A. They were rarely the primary purpose of deep-sea exploration.

B. The people who conducted experiments were not professional scientists.

C. Many people refused to believe the discoveries that were made.

D. They involved the use of technologies from other disciplines.

Questions 31 – 36 (YES/NO/NOT GIVEN)

Do the following statements agree with the views of the writer in Reading Passage 3? 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

31. The Midocean Ridge is largely the same as when the continents emerged.

32. We can make an approximate calculation of the percentage of the ocean in which sunlight penetrates.

33. Many unexpected scientific phenomena came to light when the exploration of the Midocean Ridge began.

34. The number of people exploring the abyss has risen sharply in the 21st century.

35. One danger of the darkness is that deep-sea vehicles become entangled in vegetation.

36. The construction of submersibles offers little protection from the cold at great depths.

Questions 37 – 40 (Summary Completion)

Complete the summary using the list of words A – I below.
Write your answers in the boxes next to 37 – 40 on your answer sheet

Deep diving craft

A diving craft has to be 37 …………………………………enough to cope with the enormous pressure of the abyss, which is capable of crushing almost anything. Unlike creatures that live there, which are not 38……………………………………..…. because they contain compressed water, a submersible is filled with 39…………………………………………….. If it has a weak spot in its construction, there will be a 40…………………………………… explosion of water into the craft.

List of words:

A. an ocean

B. air

C. deep

D. hollow

E. sturdy

F. atmosphere

G. energetic

H. violent

I. heavy

Summary of the Reading Passage

The passage explores the history and challenges of deep-sea exploration.

• Paragraph A: Compares the irony of humans knowing more about space than the ocean floor. Introduces the Midocean Ridge, the largest mountain range on Earth located underwater.

• Paragraph B: Points out that the 71% surface figure underestimates the ocean’s importance, as 97% of the biosphere lies in the deep, lightless layers. Recounts the history of diving devices from 16th-century diving bells to the Beebe and Barton submersible in 1930.

• Paragraph C: Discusses the 1970s turning point when manned submersibles reached the Midocean Ridge, leading to a series of scientific discoveries. Describes challenges: darkness, light absorption, and radio signal interference.

• Paragraph D: Other challenges: bone-chilling cold (water absorbs heat quickly) and immense pressure (thousands of times higher than at sea level).

• Paragraph E: Compares the adaptation of fish (filled with water) and submersibles (hollow chambers). Submersibles must withstand extreme pressure; if they breach, it causes a laser-like, explosive influx of water.

Key Vocabulary from “The Deep Sea”

1. Celestial neighbour (n.p) (Paragraph A): A nearby celestial body (referring to the Moon/planets).

2. Penetrate (v) (Paragraph A, B, C): To enter or pass through something.

   • Example: “…before penetrating just two miles deep into the Earth’s own waters…”

3. Submarine landscapes (n.p) (Paragraph A): Underwater scenery.

4. Ingenuity (n) (Paragraph B): The quality of being clever, original, and inventive (in design/engineering).

   • Example: “In terms of technical ingenuity…”

5. Incidental (adj) (Paragraph B): Happening as a minor accompaniment; not the primary purpose.

   • Example: “Science then was largely incidental…”

6. Abyss (n) (Paragraph C, D): A deep or seemingly bottomless chasm (the deep ocean floor).

7. Dissipate (v) (Paragraph C): To scatter or disappear (signals, energy).

8. Insulation (n) (Paragraph D): Material used to prevent the passage of heat or electricity.

   • Example: “…submersibles rarely have much insulation.”

9. Withstand (v) (Paragraph E): To remain undamaged or unaffected by; resist.

   • Example: “That chamber must withstand the full brunt of deep-sea pressure…”

Answers and Detailed Explanations

27. Answer: C (people reached the moon before they explored the deepest parts of the Earth’s oceans.)

• Explanation: The author finds it incredible that humans traveled to our “celestial neighbour” (the Moon) before descending just two miles into the ocean.

• Evidence (Paragraph A): “It is incredible that human beings crossed a quarter of a million miles of space to visit our nearest celestial neighbour before penetrating just two miles deep…”

28. Answer: A (ignores the depth of the world’s oceans.)

• Explanation: The author argues that the 71% figure is inaccurate (it “understates” the importance) because it only considers surface area, ignoring volume (depth).

• Evidence (Paragraph B): “The figure… 71% of the Earth’s surface – understates the oceans’ importance. If you consider three-dimensional volumes instead…”

29. Answer: C (It offered access to a reservoir of air below the surface.)

• Explanation: The diving bell provided a pocket of air for divers to breathe underwater without needing to return to the surface.

• Evidence (Paragraph B): “…they could swim to the bell to breathe air trapped underneath it rather than return to the surface.”

30. Answer: A (They were rarely the primary purpose of deep-sea exploration.)

• Explanation: In the early stages (1930), science was largely “incidental,” not the main goal.

• Evidence (Paragraph B): “Science then was largely incidental – something that happened along the way.”

Questions 31-36 (YES/NO/NOT GIVEN)

31. Answer: NO

• Question: The Midocean Ridge is largely the same as when the continents emerged.

• Evidence (Paragraph A): “…where vast volcanoes continue to create new submarine landscapes.”

• Explanation: Volcanoes are “continuing to create new landscapes,” meaning it is constantly changing, not remaining the same.

32. Answer: YES

• Question: We can make an approximate calculation of the percentage of the ocean in which sunlight penetrates.

• Evidence (Paragraph B): “The upper sunlit layer, by one estimate, contains only 2 or 3% of the total space…”

• Explanation: “By one estimate” corresponds to “approximate calculation.”

33. Answer: YES

• Question: Many unexpected scientific phenomena came to light when the exploration of the Midocean Ridge began.

• Evidence (Paragraph C): “…begin making major contributions… A burst of discoveries followed… Several of these profoundly changed the whole field of science…”

• Explanation: “A burst of discoveries” corresponds to “many unexpected scientific phenomena.”

34. Answer: NOT GIVEN

• Question: The number of people exploring the abyss has risen sharply in the 21st century.

• Explanation: The passage discusses exploration but does not mention the number of people or any specific increase in the 21st century.

35. Answer: NOT GIVEN

• Question: One danger of the darkness is that deep-sea vehicles become entangled in vegetation.

• Explanation: Paragraph C mentions darkness and light absorption, but says nothing about becoming entangled in vegetation.

36. Answer: YES

• Question: The construction of submersibles offers little protection from the cold at great depths.

• Evidence (Paragraph D): “…submersibles rarely have much insulation… the cold down below seems to penetrate a diving capsule far more quickly…”

• Explanation: “Rarely have much insulation” is synonymous with “little protection from the cold.”

Questions 37 – 40 (Summary Completion)

37. Answer: E (sturdy)

• Evidence (Paragraph E): “That chamber must withstand the full brunt of deep-sea pressure…”

• Explanation: To “withstand” pressure, the craft must be “sturdy.”

38. Answer: D (hollow)

• Evidence (Paragraph E): “Fish… are filled with water… A diving craft, however, is a hollow chamber…”

• Explanation: The passage contrasts fish (filled with water) and submersibles (hollow). The question states that creatures are NOT “hollow.”

39. Answer: B (air)

• Evidence: The submersible is a “hollow chamber” for humans, so it must contain air for breathing and to maintain lower internal pressure compared to the outside.

• Explanation: The craft is filled with “air” for humans, unlike fish which are filled with water.

40. Answer: H (violent)

• Evidence (Paragraph E): “…it explodes through the hole with laser-like intensity.”

• Explanation: An explosion with “laser-like intensity” is an extremely “violent” event.

Conclusion

The “The Deep Sea” reading passage is not just a language test, but a fascinating scientific story about humanity’s efforts to overcome biological limits. By analyzing the challenges of pressure, temperature, and light, the passage helps learners understand why the ocean floor is so difficult to conquer. We hope this detailed explanation from ECE English has equipped you with the vocabulary and logical thinking needed to handle reading passages about exploration and science in the IELTS exam.