Cambridge IELTS Academic 21 Reading Test 2 Answers with Explanation / IELTS Academic Reading: Cambridge 21 Test 2 Answer / Cambridge IELTS 21 Reading Test 2 Answers /কেমব্রিজ ২১ টেস্ট ২-এর উত্তর

Cambridge 21 Test 2 Reading Answers & Explanations

Reading Passage 1: Do Animals Dream?

Q	Answer	Keywords	Location	Analytical Explanation
1	rats	similar brain patterns, active, sleeping, dreaming	Reading Passage 1, Paragraph 2, lines 1–4	Researchers compared the brain patterns of rats while they were running through a maze with their brain patterns during REM sleep. The patterns were very similar, leading researchers to conclude that the sleeping animals were dreaming about the maze. Here: when active = running through a maze while awake; when sleeping = during REM sleep. The animals involved in the experiment were rats.
2	visual	pigeons, brain activity, input, flying	Reading Passage 1, Paragraph 3, lines 4–7	The passage says that REM sleep activity was high in brain regions involved in processing visual information. The activity was especially connected with images relating to physical actions such as flying. Here: parts of the brain that deal with = brain regions involved in processing; input = information. The type of information was visual.
3	half	whales, dolphins, brain awake, sleep	Reading Passage 1, Paragraph 4, lines 3–5	The passage explains that whales and dolphins do not shut down their entire brain when sleeping. They shut down only one part and keep the remainder awake. Here: do not shut down their entire brain = part of the brain stays awake. They shut down only half of it. The completed sentence becomes: Whales and dolphins still have half their brain awake when they sleep.
4	temperature	REM sleep, sensitivity, whales, dolphins	Reading Passage 1, Paragraph 4, lines 7–8	The passage says whales and dolphins may not experience REM sleep because animals are more vulnerable to extremes of temperature during this stage. Here: more vulnerable to extremes of = sensitivity to. The environmental factor is temperature.
5	vivid	dreams, whales, dolphins, non-REM sleep	Reading Passage 1, Paragraph 4, lines 5–6	Whales and dolphins show no sign of REM sleep. The passage suggests that they may experience only non-REM dreams, which are less vivid. Here: less vivid = not very vivid. The adjective fits naturally after not very.
6	TRUE	past experiences, lasting memories, dreaming	Reading Passage 1, Paragraph 5, lines 1–4	The passage says that events are replayed in dreams and that this process helps integrate memories into longer-term storage. Here: events are replayed in dreams = dreaming about past experiences; longer-term storage = lasting memories; helps to integrate memories = helps create or preserve them. The statement agrees with the passage.
7	FALSE	possible to tell, type of dream, dog	Reading Passage 1, Paragraph 6, lines 1–5	People often interpret a sleeping dog’s moving limbs and quiet barks as signs that it is chasing something. However, the writer says that we do not know whether the dog is actually having an internal experience of chasing rabbits. Here: The behaviour may suggest a particular dream. The passage says the true internal experience remains unknown. The statement contradicts the passage.
8	NOT GIVEN	David Scheel, documentary, influential, other research	Closest related location: Reading Passage 1, Paragraph 7, lines 1–4	The passage says that David Scheel was making a documentary when he observed an octopus named Heidi apparently dreaming. However, it does not state that the documentary influenced later research; that other researchers based their work on it; or that the documentary changed the study of octopus sleep.
9	FALSE	Costello, asleep, reacted, hunting	Reading Passage 1, Paragraph 8, lines 1–3	Costello moved violently, made himself look larger and released ink as though he were being attacked by a predator. Here: being attacked by a predator = acting like prey defending itself; hunting = acting as the predator. The passage describes Costello as reacting to an attack, not hunting another animal.
10	TRUE	Scheel, more research, octopus dreams	Reading Passage 1, Paragraph 8, lines 3–6	Scheel says the nightmare study is based on only one animal. He argues that brain imaging is also needed to demonstrate that octopuses replay waking experiences in their dreams. Here: only based on one animal = the evidence is limited; brain imaging is needed = additional research is necessary. The statement agrees with his view.
11	FALSE	soon, share dreams, other humans	Reading Passage 1, Paragraph 9, lines 1–2	The writer says that humans will never be able to experience the dreams of animals. The same limitation applies to the dreams of other people. Here: never be able to experience contradicts may soon be able to share. The writer presents the limitation as permanent.
12	NOT GIVEN	hearing, important, dreams, animals	Closest related location: Reading Passage 1, Paragraph 9, lines 3–5	The passage explains that different species experience the world through different dominant senses: humans rely heavily on vision; dogs mainly use smell; spiders rely strongly on vibrations. However, the passage does not mention hearing as a dominant sense, animals hearing things in their dreams, or the role of sound in animal dreams.
13	NOT GIVEN	interest, reasons humans dream, increased, recent times	Closest related location: Reading Passage 1, Paragraph 10, lines 1–3	The final paragraph says that understanding the different purposes of animal dreams might help explain the purpose of human dreams. However, it does not discuss whether public or scientific interest has increased, the level of previous interest, or any recent change in attention to the subject.

Reading Passage 2: Mapungubwe

Q	Answer	Keywords	Location	Analytical Explanation
14	E	uncertainty, purpose, certain objects	Reading Passage 2, Paragraph E, lines 5–7	The passage describes animal and human figures discovered at Mapungubwe. It suggests that they may have been used in ceremonies as offerings to ancestors. However, their exact function is unknown. Here: precise function is not known = uncertainty about their purpose. The objects are the discovered figurines.
15	G	climatic factor, increased problems, decline	Reading Passage 2, Paragraph G, lines 1–4	The kingdom was already declining because overpopulation placed pressure on local resources. The passage says that a series of droughts may have brought the situation to a crisis point. Here: droughts = climatic factor; brought to a crisis point = increased or intensified the problems. "may have" shows likelihood rather than certainty.
16	C	location, king’s family, lived, relatives	Reading Passage 2, Paragraph C, lines 4–5	The passage says that grander residences were located around the outskirts of Babandyanalo. These homes probably belonged to male relatives of the king. Here: male relatives of the king = members of the king’s family; around the outskirts of Babandyanalo = where they lived.
17	D	people, brought goods, ship, trade	Reading Passage 2, Paragraph D, lines 4–5	Glass beads found at the site probably came from India. The passage says coastal states traded with merchants travelling from India by sea. Here: merchants = people involved in trade; travelling from India by sea = bringing goods by ship.
18	B	estimate, size, community, population	Reading Passage 2, Paragraph B, lines 1–2	The passage estimates that Mapungubwe’s population reached approximately 5,000 people at its peak in the middle of the 13th century. Here: total population at its peak = size to which the community grew; around 5,000 = an estimate.
19	A	agricultural produce, exchanged, other items	Reading Passage 2, Paragraph A, lines 4–5	Cattle herding and other farming activities produced plenty of food and a surplus. This surplus could be traded for goods the community needed. Here: food and a surplus = agricultural produce; traded for needed goods = exchanged for other items.
20 & 21	B and D	gold, archaeological record, Mapungubwe, two pieces of information	Reading Passage 2, Paragraph F, lines 1–8	The passage gives two relevant details. First, gold objects were found at the royal burial site (royal burial site = the place where Mapungubwe’s rulers were buried), supporting Option B. Second, a particular method of gold decoration was found nowhere else except Great Zimbabwe (same decoration method existed in another kingdom), supporting Option D.
22	prosperity	professionally made pottery, indicates, community	Reading Passage 2, Paragraph E, lines 1–3	The passage says pottery was produced on a scale large enough to suggest professional potters. This is described as an indicator of Mapungubwe society’s prosperity. Here: indicator of = indicates. The quality and quantity of pottery demonstrate the society’s prosperity.
23	whistles	ceramic objects, animal figures, other discoveries	Reading Passage 2, Paragraph E, lines 4–5	The passage lists ceramic discs and whistles before describing cattle, sheep and goat figurines. Here: round ceramic objects = ceramic discs. The next separate objects in the list are whistles.
24	bodies	models of people, stretched, stylised humans	Reading Passage 2, Paragraph E, lines 5–6	The passage describes small figures of highly stylised humans with elongated bodies and short limbs. Here: models of people = figures of humans; stretched = elongated. The elongated parts were their bodies.
25	ancestors	figures, ceremonies, honour	Reading Passage 2, Paragraph E, lines 6–7	The passage suggests that the figures may have been used as offerings during ceremonies for ancestors. Here: offerings to = used to honour. The people being honoured were ancestors.
26	jewellery / jewelry	pieces, local metal, discovered	Reading Passage 2, Paragraph E, lines 7–8	The passage says small jewellery items made from locally sourced copper were found. Here: local metal = locally sourced copper; pieces of = small items of. The objects were jewellery.

Reading Passage 3: Artificial Intelligence

Q	Answer	Keywords	Location	Analytical Explanation
27	B	writer doing, first paragraph, public view, AI	Reading Passage 3, Paragraph 1, lines 1–4	The writer describes widespread excitement and fear about AI in Western countries. Sensationalist media reports suggest that AI can cure diseases, increase innovation and improve creativity. The writer is not personally predicting what AI will do. Instead, the paragraph describes how AI is publicly presented and perceived.
28	A	AI solutionism, second paragraph, danger, risk	Reading Passage 3, Paragraph 2, lines 1–6	The writer defines AI solutionism as the belief that machine-learning algorithms can solve all human problems if they are given enough data. The writer then warns that this attitude may damage AI progress by ignoring safety principles, creating unrealistic expectations, and weakening the value of machine intelligence. This means the writer identifies a danger associated with AI solutionism.
29	C	politicians, fourth paragraph, national AI initiatives, implementation	Reading Passage 3, Paragraph 4, lines 1–4	Governments are investing in national AI initiatives and competing to lead the machine-learning sector. However, the writer says many politicians fail to understand the complexity of deploying advanced machine-learning systems in real-world situations. Here: fail to realise the complexity = are unaware of the challenges; deploying systems in the real world = implementing AI initiatives.
30	F — equality	neural network, government, inclusive, fair	Reading Passage 3, Paragraph 5, lines 3–5	The writer says adding a neural network to a government system does not automatically make it more inclusive or fair. Here: inclusive or fair = promoting equality. The summary describes what politicians may incorrectly expect. Among the options, equality best matches the idea of fairness and inclusion.
31	G — framework	public sector, necessary, manage data, infrastructure	Reading Passage 3, Paragraph 6, lines 1–3	The passage says AI requires large amounts of data, but the public sector usually lacks the appropriate data infrastructure needed to support advanced machine learning. Here: data infrastructure = organisational and technical framework. Necessary framework fits the summary grammatically and logically.
32	I — approval	access data, departments, special permissions	Reading Passage 3, Paragraph 6, lines 3–5	Data is distributed across different government departments. The passage says each department requires special permissions before its information can be accessed. Here: special permissions = approval. A person needs approval to gain access.
33	C — skills	employees, technological capabilities, benefits	Reading Passage 3, Paragraph 6, lines 5–7	The passage says the public sector lacks people with the right technological capabilities to make full use of machine intelligence. Here: technological capabilities = skills; human talent with the right capabilities = employees with the necessary skills.
34	A — reliability	medical experts, little faith, programme, trust	Reading Passage 3, Paragraph 11, lines 1–4	IBM Watson for Oncology was designed to provide doctors with the best treatment recommendations. However, human experts found it difficult to trust the system, and it was abandoned in most hospitals where it was tested. Here: found it hard to trust = had little faith in. The quality being questioned was its reliability.
35	D — prejudices	court algorithms, magnified, discrimination, legal profession	Reading Passage 3, Paragraph 12, lines 1–4	The system used risk-assessment scores to advise judges during sentencing. It was found to amplify structural racial discrimination. Here: amplify = magnify; structural racial discrimination = existing racial prejudices. Among the options, prejudices is the closest match.
36	NO	Stuart Russell, proposals, impractical	Reading Passage 3, Paragraph 7, lines 1–4	The writer says Stuart Russell supports a sensible and realistic approach that focuses on simple everyday uses of AI. Here: sensible and realistic contradicts impractical. The writer presents Russell’s approach positively.
37	NOT GIVEN	Rodney Brooks, unfair criticism, AI supporters	Closest related location: Reading Passage 3, Paragraph 7, lines 4–6	Rodney Brooks argues that most innovations in robotics and AI take much longer to become widely used than people expect. However, the passage does not mention criticism of Brooks, whether any criticism was unfair, or whether supporters of AI disagreed with him.
38	NO	protect AI systems, always considered, installed	Reading Passage 3, Paragraph 8, lines 1–6	The passage discusses the danger of adversarial attacks and says researchers have warned against introducing AI without security standards. However, AI security remains an often overlooked subject when machine-learning systems are installed. Here: often overlooked contradicts always considered.
39	YES	benefit, reduce harm, concerns, distrust	Reading Passage 3, Paragraph 9, lines 1–4	The writer says that gaining AI’s benefits while minimising its harms requires discussion about AI ethics, meaningful applications, and the distrust many people feel towards machine learning. Here: distrust = people’s concerns; discussion about distrust = exploring those concerns. The statement agrees with the writer.
40	B	suitable subtitle, main message, AI limitations, solution	Reading Passage 3, Paragraph 13, lines 1