Coral Reefs Under Pressure: Reading Answers & Explanations
IELTS Reading practice test · 14 questionsAcademicmedium
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About this passage
The passage opens: “Coral reefs are often described as the rainforests of the sea, and the comparison is apt. Although they cover only a tiny fraction of the ocean floor, they shelter a startling proportion of all marine species, providing food and refuge for fish, molluscs, crustaceans and countless smaller creatures.”
- Passage length: about 754 words
- Questions: 14
- Question types: True / False / Not Given, Multiple Choice, Short Answer
“Coral Reefs Under Pressure” is an original IELTS-style practice passage written by IELTS-Bank. It is not taken from an official IELTS or Cambridge test, so these answers only apply to our version.
Answer key at a glance
Coral Reefs Under Pressure answers with explanations
Questions 1–6: True / False / Not Given
Do the following statements agree with the information given in the passage? Write TRUE if the statement agrees, FALSE if it contradicts, or NOT GIVEN if there is no information.
- 1
Coral reefs occupy only a small part of the ocean floor.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 1 “Although they cover only a tiny fraction of the ocean floor, they shelter a startling proportion of all marine species”
- 2
A single coral polyp builds an entire reef by itself.
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Answer: FALSE
Why: This sentence directly contradicts the statement, so the answer is FALSE.
Evidence · Paragraph 2 “A coral is not a single creature but a colony of many... these skeletons accumulate over thousands of years into the massive structures we call reefs.”
- 3
The algae living inside coral supply it with much of its energy.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 3 “These algae capture sunlight and, through photosynthesis, produce sugars that supply the coral with much of the energy it needs to grow and build its skeleton.”
- 4
A coral that has bleached is always dead and can never recover.
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Answer: FALSE
Why: This sentence directly contradicts the statement, so the answer is FALSE.
Evidence · Paragraph 4 “A bleached coral is not dead, and if cooler conditions return quickly enough the algae may recolonise it and the coral may recover.”
- 5
Ocean acidification is caused by carbon dioxide dissolving into the sea.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 5 “…a portion of that gas dissolves into the sea. There it reacts with seawater to form a weak acid, gradually lowering the water's natural alkalinity in a process called ocean acidification.”
- 6
Coral reefs are found in greater numbers in the Pacific Ocean than elsewhere.
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Answer: NOT GIVEN
Why: The statement claims coral reefs are more numerous in the Pacific Ocean, but the passage does not confirm or deny this, focusing instead on the ecological roles and threats to coral reefs in general.
Question 7: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. Because corals move quickly through the water
- B. Because the animals that build reefs are small and simple
- C. Because reefs are found only in deep water
- D. Because corals have no colour of their own
- 7
Why did early naturalists misunderstand what corals were?
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Answer: B — Because the animals that build reefs are small and simple
Why: This is the part of the passage that supports B — Because the animals that build reefs are small and simple.
Evidence · Paragraph 1 “…these vast, colourful structures are built by animals so small and simple that early naturalists mistook them for plants or even stones.”
Question 8: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. Because the water there is warmest
- B. Because that is where their predators cannot reach
- C. Because their algae need enough light for photosynthesis
- D. Because deeper water lacks the minerals they need
- 8
Why do reef-building corals live only in clear, shallow water?
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Answer: C — Because their algae need enough light for photosynthesis
Why: This is the part of the passage that supports C — Because their algae need enough light for photosynthesis.
Evidence · Paragraph 3 “…reef-building corals thrive only in clear, shallow, sunlit water, where the algae can gather enough light.”
Question 9: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. They grow their skeletons more quickly
- B. They expel the algae living within them and lose their colour
- C. They release large amounts of carbon dioxide
- D. They move to cooler water
- 9
What happens to corals during a bleaching event?
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Answer: B — They expel the algae living within them and lose their colour
Why: This is the part of the passage that supports B — They expel the algae living within them and lose their colour.
Evidence · Paragraph 4 “Stressed corals expel the algae living within them, losing both their main food supply and their colour. The result is a phenomenon known as coral bleaching, in which whole reefs turn a ghostly white.”
Question 10: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. It makes it harder for them to build their skeletons
- B. It increases the light reaching their algae
- C. It kills their predators
- D. It raises the temperature of the water
- 10
According to the passage, how does ocean acidification affect corals?
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Answer: A — It makes it harder for them to build their skeletons
Why: This is the part of the passage that supports A — It makes it harder for them to build their skeletons.
Evidence · Paragraph 5 “This change makes it harder for corals to obtain the minerals they need to build their limestone skeletons, slowing their growth and weakening the structures they have already made.”
Questions 11–14: Short Answer
Answer the questions below. Choose NO MORE THAN THREE WORDS from the passage for each answer.
- 11
What is each individual coral animal called?(max 2 words)
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Answer: a polyp (also accepted: polyp)
Why: The answer “a polyp” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 2 “Each individual, called a polyp, is a soft-bodied animal”
- 12
What hard material do reef-building corals lay down beneath their bodies?(max 3 words)
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Answer: limestone (also accepted: a skeleton of limestone / limestone skeleton)
Why: The answer “limestone” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 3-word limit.
Evidence · Paragraph 2 “…lay them down as a hard skeleton of limestone beneath their bodies.”
- 13
What can be washed from cleared land to cloud the water and block sunlight?(max 2 words)
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Answer: sediment
Why: The answer “sediment” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 6 “Sediment washed from cleared land can cloud the water and block the sunlight the algae depend on.”
- 14
Where are some scientists growing corals before transplanting them onto damaged reefs?(max 2 words)
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Answer: nurseries (also accepted: in nurseries / coral nurseries)
Why: The answer “nurseries” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 7 “…attempts to grow corals in nurseries and transplant them onto damaged reefs”
Estimated band score for this test
Your raw score out of 14 scaled to the 40-question IELTS Reading (Academic) conversion table. This is the same estimate the practice page shows after you submit. A single passage is a small sample, so treat it as a guide.
| Correct answers | Estimated band |
|---|---|
| 14 / 14 | 9.0 |
| 13 / 14 | 8.5 |
| 12 / 14 | 7.5 |
| 11 / 14 | 7.0 |
| 10 / 14 | 6.5 |
| 8–9 / 14 | 6.0 |
| 7 / 14 | 5.5 |
| 6 / 14 | 5.0 |
| 5 / 14 | 4.5 |
| 4 / 14 | 4.0 |
| 3 / 14 | 3.5 |
| 2 / 14 | 3.0 |
| 1 / 14 | 2.0 |
| 0 / 14 | 0.0 |
Full-test score? Use the IELTS band calculator.
Tips for the question types in this test
True / False / Not Given
- Read the statement first and underline the key idea, especially any qualifiers like "all", "only", "never", "always", "more than" or dates and numbers.
- Because the questions follow the order of the passage, scan for the paragraph that deals with the same topic rather than re-reading everything.
Common trap: Confusing "False" with "Not Given": choose False only when the passage actively contradicts the statement; if the passage is silent, it is Not Given.
Full True / False / Not Given strategyMultiple Choice
- Read the question stem carefully before the options so you know exactly what is being asked.
- Because multiple-choice questions follow passage order, locate the relevant section and read it in full — the answer usually depends on more than one sentence.
Common trap: Distractors that use exact words from the passage but distort the meaning.
Full Multiple Choice strategyShort Answer
- Read the instructions and note the exact word limit; going over it means zero marks even if the meaning is right.
- Turn each question into a set of keywords and predict what kind of answer it needs (a person, a date, a place, a noun).
Common trap: Exceeding the word limit (writing four words when only three are allowed).
Full Short Answer strategyPractise “Coral Reefs Under Pressure” under exam conditions
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