All answers on this page include the question number, correct answer and a brief explanation of where to find it in the passage or audio. Use these alongside the original Cambridge IELTS books for the best practice experience.
Test 2 answers with clear explanations
These Cambridge IELTS 21 Test 2 Reading answers explain all 40 questions. Review the evidence for Do Animals Dream?, Mapungubwe, and Artificial Intelligence.
Cambridge IELTS 21 Test 2 Reading answer key
Use these cards for quick marking. Review the passage sections when an answer needs more attention.
1. Do Animals Dream?
Questions 1 to 132. Mapungubwe
Questions 14 to 263. Artificial Intelligence
Questions 27 to 40Passage 1: Do Animals Dream?
Do Animals Dream? examines REM sleep, animal brain activity, and dream evidence in rats, pigeons, whales, dolphins, and octopuses. It compares visible sleep behaviour with the limits of knowing an animal's inner experience.
Question types: Table completion and True, False, Not Given.
Where to look: Paragraph 2.
Why: Researchers compared brain patterns from rats running through a maze with their patterns during REM sleep.
Where to look: Paragraph 3.
Why: Sleeping pigeons showed strong activity in brain regions that process visual information.
Where to look: Paragraph 4.
Why: Whales and dolphins shut down only half of the brain. The other half stays awake.
Where to look: Paragraph 4.
Why: REM sleep makes animals more vulnerable to extreme temperatures. Whales and dolphins avoid this risk.
Where to look: Paragraph 4.
Why: Their non-REM dreams are described as less vivid. The gap needs the adjective vivid.
Why: Replaying events during dreams helps move memories into longer-term storage.
Why: The passage says a dog's movements do not reveal its internal dream experience.
Why: The documentary records Heidi's behaviour. The passage never says it influenced the later octopus report.
Common note: A sequence of events does not prove that one caused the other.
Why: Costello acted as though a predator was attacking him. He was not described as hunting.
Why: Scheel says researchers need brain imaging as well as observations of outward behaviour.
Why: The writer says we can never experience another animal's dreams or another human's dreams.
Why: The passage discusses smell, vibrations and vision. It gives no information about hearing.
Why: The writer says animal research may explain human dreams. No change in public or scientific interest is described.
Passage 2: Mapungubwe
Mapungubwe describes the rise, trade, archaeology, and decline of a medieval southern African kingdom near the Limpopo River. It covers cattle wealth, royal settlements, pottery, gold artefacts, and international trade links.
Question types: Matching information, multiple selection, and summary completion.
Why: Paragraph E says the human and animal figures may have served ceremonies. Their exact function remains unknown.
Why: Paragraph G says droughts may have pushed resource pressure towards a crisis.
Why: Paragraph C places the likely homes of male royal relatives around the outskirts of Babandyanalo.
Why: Paragraph D describes merchants travelling from India by sea to coastal trading states.
Why: Paragraph B estimates that Mapungubwe reached about 5,000 people in the mid-13th century.
Why: Paragraph A says farming produced extra food that people traded for needed goods.
Why: Gold objects were found at the royal burial site. This supports option B.
Common note: Questions 20 and 21 accept B and D in either order.
Also accepted: D.
Why: The gold-sheet decoration also appeared in Great Zimbabwe. This supports option D.
Also accepted: B.
Where to look: Paragraph E.
Why: Professional pottery production is presented as evidence of Mapungubwe's prosperity.
Where to look: Paragraph E.
Why: The list of ceramic objects includes discs and whistles before the animal figures.
Where to look: Paragraph E.
Why: The stylised human figures have elongated bodies and short limbs. Elongated means stretched.
Where to look: Paragraph E.
Why: The figures may have been offerings used in ceremonies for ancestors.
Where to look: Paragraph E.
Why: Archaeologists found small jewellery items made from locally sourced copper.
Also accepted: jewelry.
Passage 3: Artificial Intelligence
Artificial Intelligence challenges AI solutionism and unrealistic claims about machine learning in government. It examines data systems, security, ethics, medical AI, and biased legal algorithms.
Question types: Multiple choice, summary completion, and Yes, No, Not Given.
Why: The writer describes a widespread public picture of AI created by sensational media coverage.
Why: The writer warns that AI solutionism ignores safety and creates unrealistic expectations. This is a risk.
Why: Many politicians fail to recognise the difficulty of deploying machine learning in real government systems.
Why: Politicians assume neural networks will make government more inclusive or fair. The matching word is equality.
Why: Public bodies often lack the data infrastructure needed for advanced machine learning. Framework matches this system.
Why: Government departments require special permissions before their data can be accessed. The matching word is approval.
Why: The public sector lacks people with the technological capabilities needed to use AI. The answer is skills.
Why: Doctors found it hard to trust the programme's recommendations. Their concern was reliability.
Why: The legal algorithm amplified structural racial discrimination. The matching word is prejudices.
Why: Russell supports a sensible and realistic approach using simple everyday AI. The statement gives the opposite view.
Why: The passage reports Brooks' view about slow deployment. It does not mention criticism of him.
Why: The writer says AI security is often overlooked when machine learning systems are installed.
Why: The writer calls for discussion about AI ethics and people's distrust of machine learning.
Why: The passage repeatedly challenges AI solutionism. It explains why AI cannot solve every problem.
What to do after marking
Group each mistake by cause. Use 1 label: location error, meaning error, question-rule error, or time pressure. Then repeat the weakest question type.
Related Cambridge IELTS 21 practice
Source note: This answer guide supports Cambridge IELTS 21 Academic Test 2. IELTSBeacon wrote each explanation independently from the passage evidence. IELTS is a registered trademark of its owners. IELTSBeacon is not affiliated with Cambridge University Press & Assessment.