The Formation of River Deltas: Reading Answers & Explanations
IELTS Reading practice test · 14 questionsAcademicmedium
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About this passage
The passage opens: “Where a river meets the sea or a lake, it often builds a broad, fan-shaped expanse of low-lying land known as a delta. These features are among the most fertile and densely populated places on Earth, home to some of the world's great cities and to vast areas of productive farmland.”
- Passage length: about 744 words
- Questions: 14
- Question types: True / False / Not Given, Multiple Choice, Short Answer
“The Formation of River Deltas” 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
The Formation of River Deltas answers with explanations
Questions 1–6: True / False / Not Given
Do the following statements agree with the information given in the passage? Write TRUE, FALSE or NOT GIVEN.
- 1
A delta is a permanent and unchanging piece of solid ground.
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Answer: FALSE
Why: This sentence directly contradicts the statement, so the answer is FALSE.
Evidence · Paragraph 1 “…a delta is not a permanent, solid piece of ground so much as a slowly shifting deposit, constantly being built up and worn away by the interplay of river and sea.”
- 2
A river drops its sediment when its current slows on reaching still water.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 2 “…when the river reaches the still water of the sea or a lake, its current slows abruptly. Deprived of the energy needed to carry its load, the river drops the sediment it has been transporting.”
- 3
A delta can only grow where the river delivers more sediment than the sea removes.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 3 “The building of a delta therefore depends on the river delivering more sediment than the sea can carry away... only where the supply of sediment outpaces this removal can a delta grow.”
- 4
The smaller branches that spread across a delta always remain in fixed positions.
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Answer: FALSE
Why: This sentence directly contradicts the statement, so the answer is FALSE.
Evidence · Paragraph 4 “These channels are not fixed. Over time a channel may become blocked with its own sediment, forcing the water to break out and find a new route.”
- 5
Deltas contain a larger share of the world's population than any other type of landscape.
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Answer: NOT GIVEN
Why: The statement claims deltas contain a larger share of the world's population than any other landscape, but the passage never confirms or denies this, only mentioning that deltas are densely populated and fertile.
Closest related text · Paragraph 1 “These features are among the most fertile and densely populated places on Earth, home to some of the world's great cities and to vast areas of productive farmland.”
- 6
Dams built upstream can prevent sediment from reaching a delta.
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Answer: TRUE
Why: This sentence confirms the statement, so the answer is TRUE.
Evidence · Paragraph 7 “The building of dams and other structures upstream can trap sediment before it ever reaches the delta, starving the coast of the material it needs to maintain itself.”
Question 7: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. solid rock eroded from cliffs
- B. sediment such as sand, silt and clay carried by a river
- C. salt deposited by the sea
- D. volcanic ash from nearby eruptions
- 7
What is a delta created from?
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Answer: B — sediment such as sand, silt and clay carried by a river
Why: This is the part of the passage that supports B — sediment such as sand, silt and clay carried by a river.
Evidence · Paragraph 2 “A delta is created from sediment, the fine particles of sand, silt and clay that a river carries along its course.”
Question 8: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. the temperature of the water
- B. the depth of the sea alone
- C. the balance between the river and forces such as waves and tides
- D. the age of the river
- 8
What determines the shape a delta takes?
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Answer: C — the balance between the river and forces such as waves and tides
Why: This is the part of the passage that supports C — the balance between the river and forces such as waves and tides.
Evidence · Paragraph 3 “The shape a delta takes reflects the balance between these opposing forces. Where the river dominates, the delta may extend far out to sea in long fingers; where waves or tides are strong, the deposited sediment is reworked into smoother, more rounded forms.”
Question 9: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. because the soil was reliably fertile and could support agriculture
- B. because deltas were safe from all flooding
- C. because deltas were far from the sea
- D. because the land was high above sea level
- 9
Why did many early civilisations arise on deltas?
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Answer: A — because the soil was reliably fertile and could support agriculture
Why: This is the part of the passage that supports A — because the soil was reliably fertile and could support agriculture.
Evidence · Paragraph 5 “Many of the earliest civilisations arose on deltas and river floodplains precisely because the reliable fertility of the soil could support intensive agriculture and large populations.”
Question 10: Multiple Choice
Choose the correct letter, A, B, C or D.
- A. it grows more quickly
- B. it may begin to shrink
- C. it becomes higher above sea level
- D. its channels stop shifting
- 10
What may happen to a delta when its sediment supply is cut off but erosion continues?
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Answer: B — it may begin to shrink
Why: This is the part of the passage that supports B — it may begin to shrink.
Evidence · Paragraph 7 “When the supply of sediment is cut off while erosion by the sea continues, a delta may begin to shrink, and land that took thousands of years to build can be lost.”
Questions 11–14: Short Answer
Answer the questions below. Choose NO MORE THAN THREE WORDS from the passage for each answer.
- 11
What general term describes the fine particles of sand, silt and clay carried by a river?(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 2 “A delta is created from sediment, the fine particles of sand, silt and clay that a river carries along its course.”
- 12
What are the smaller branches into which a main river channel divides on a delta called?(max 2 words)
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Answer: distributaries
Why: The answer “distributaries” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 4 “…the main river channel often divides into a network of smaller branches, called distributaries, that spread across the delta.”
- 13
In the past, what regularly renewed the fertility of delta soils?(max 2 words)
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Answer: flooding (also accepted: regular flooding)
Why: The answer “flooding” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 5 “…in the past regular flooding renewed this fertility by spreading a fresh layer of material across the land.”
- 14
Besides trapping sediment, the extraction of water can cause the surface of a delta to do what?(max 2 words)
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Answer: sink
Why: The answer “sink” is taken from this sentence — copy the word(s) exactly as they appear. It fits the 2-word limit.
Evidence · Paragraph 7 “…the extraction of water and other resources can cause the surface of a delta to sink, making it still more exposed to the sea.”
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 “The Formation of River Deltas” under exam conditions
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