INSTRUCTIONS TO CANDIDATES

• Read the instructions for each part of the paper carefully.
• Answer ALL the questions.
• You must complete the answer sheet within the time limit.
• At the end of the test, hand in both this question paper and your answer sheet.

INFORMATION FOR CANDIDATES

• There are 40 questions in this test.
• Each question carries one mark.
• The test consists of three sections.

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SECTION 1: Questions 1–13

Read the passage below and answer Questions 1–13.

The Science of Sleep

A Sleep remains one of the most fascinating yet poorly understood aspects of human biology. Despite spending approximately one-third of our lives asleep, scientists have only recently begun to unravel the complex mechanisms governing this essential physiological process. Far from being a passive state of unconsciousness, sleep involves intricate patterns of brain activity that serve critical functions for physical health, cognitive performance, and emotional regulation. Modern research has transformed our understanding of why we sleep and what consequences arise when sleep is compromised.

B The architecture of sleep follows a predictable cyclical pattern throughout the night. Upon falling asleep, individuals enter non-rapid eye movement (NREM) sleep, which progresses through three distinct stages of increasing depth. Stage one represents the transition from wakefulness, lasting only a few minutes as brain waves begin to slow. Stage two constitutes light sleep, characterised by brief bursts of electrical activity called sleep spindles, which researchers believe play a role in memory consolidation. Stage three, known as slow-wave or deep sleep, features the slowest brain waves and proves most difficult to interrupt. Following NREM sleep, the brain enters rapid eye movement (REM) sleep, during which vivid dreaming occurs and brain activity resembles that of waking consciousness. A complete sleep cycle lasts approximately ninety minutes, with individuals typically experiencing four to six cycles per night.

C The regulatory mechanisms controlling sleep involve two primary systems operating in parallel. The circadian rhythm, governed by an internal biological clock located in the hypothalamus, generates approximately twenty-four-hour cycles of alertness and drowsiness regardless of prior sleep. This system responds primarily to light exposure, synchronising internal rhythms with the external environment. The second mechanism, termed sleep homeostasis, tracks accumulated wakefulness and generates increasing pressure to sleep as time awake extends. These two systems normally work in concert, with circadian alertness declining in evening hours just as homeostatic sleep pressure peaks, facilitating sleep onset. However, disruptions to either system—through shift work, jet lag, or irregular schedules—can produce significant sleep difficulties.

D Contemporary research has identified numerous critical functions served by adequate sleep. Memory consolidation represents perhaps the most thoroughly documented benefit, with studies demonstrating that sleep enhances retention of both factual information and procedural skills. During sleep, the brain appears to replay and strengthen neural connections formed during waking learning experiences. The glymphatic system, discovered only in 2012, provides another compelling explanation for sleep's necessity. This network of channels surrounding blood vessels activates primarily during sleep, clearing metabolic waste products from brain tissue—including beta-amyloid proteins associated with Alzheimer's disease. Additionally, sleep deprivation impairs immune function, increases inflammation, and disrupts hormonal regulation of appetite, potentially contributing to obesity and metabolic disorders.

E The consequences of insufficient sleep extend beyond individual health to affect broader social and economic outcomes. Drowsy driving causes thousands of traffic fatalities annually, with sleep-deprived drivers exhibiting impairment comparable to alcohol intoxication. Workplace productivity suffers substantially when employees are under-rested, with estimates suggesting sleep deprivation costs developed economies billions in lost output. Medical errors increase significantly when healthcare professionals work extended shifts without adequate rest. Perhaps most concerning, chronic sleep restriction appears cumulative in its effects; research indicates that individuals cannot fully compensate for accumulated sleep debt through occasional extended sleep, suggesting that consistent adequate sleep represents a non-negotiable biological requirement.

F Despite growing scientific understanding of sleep's importance, modern societies increasingly compromise sleep in favour of productivity, entertainment, and social engagement. Artificial lighting, electronic devices, and round-the-clock connectivity have disrupted natural sleep patterns that prevailed throughout human evolutionary history. Adolescents prove particularly vulnerable, as biological changes during puberty shift circadian rhythms toward later sleep timing, conflicting with early school start times. Public health experts have begun advocating for policy changes recognising sleep as a fundamental component of wellbeing, including later school start times for teenagers and limitations on extended work shifts in safety-critical occupations. Whether such recommendations will overcome cultural attitudes valorising sleep deprivation as evidence of dedication remains uncertain.

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Questions 1–4

Choose the correct letter, A, B, C or D.

Write the correct letter in boxes 1–4 on your answer sheet.

1 According to the passage, sleep spindles occur during {{ANSWER:1}}

A      stage one of NREM sleep.

B      stage two of NREM sleep.

C      stage three of NREM sleep.

D      REM sleep.

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2 The glymphatic system {{ANSWER:2}}

A      was identified in the early twentieth century.

B      operates most actively while people are awake.

C      removes waste products from brain tissue during sleep.

D      is responsible for generating dreams.

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3 What does the passage suggest about recovering from sleep debt? {{ANSWER:3}}

A      Extended weekend sleep fully compensates for weekday sleep loss.

B      The effects of chronic sleep restriction cannot be completely reversed.

C      Young people recover from sleep debt faster than older adults.

D      Physical exercise helps eliminate accumulated sleep debt.

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4 The passage indicates that adolescents face particular sleep challenges because {{ANSWER:4}}

A      they require less sleep than adults.

B      their biological clocks shift toward later sleep times.

C      they are more resistant to the effects of artificial lighting.

D      schools have recently moved start times earlier.

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Questions 5–9

Do the following statements agree with the information given in the passage?

In boxes 5–9 on your answer sheet, write

5 A complete sleep cycle typically takes about ninety minutes. {{ANSWER:5}}

6 The circadian rhythm operates independently of light exposure. {{ANSWER:6}}

7 Sleep deprivation affects the immune system. {{ANSWER:7}}

8 Most developed countries have implemented later school start times for teenagers. {{ANSWER:8}}

9 Sleep-deprived drivers show similar impairment to intoxicated drivers. {{ANSWER:9}}

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Questions 10–13

The passage has six paragraphs, A–F.

Which paragraph contains the following information?

Write the correct letter, A–F, in boxes 10–13 on your answer sheet.

10 the financial impact of inadequate sleep on national economies {{ANSWER:10}}

11 a description of the different phases within a single sleep cycle {{ANSWER:11}}

12 how two biological systems coordinate to regulate sleep timing {{ANSWER:12}}

13 societal factors that have disrupted traditional sleep patterns {{ANSWER:13}}

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SECTION 2: Questions 14–26

Read the passage below and answer Questions 14–26.

Renewable Energy Storage: The Missing Link

A The transition toward renewable energy sources has accelerated dramatically over the past two decades, driven by declining costs, technological improvements, and growing concern over climate change. Solar and wind power generation have expanded from negligible contributions to electricity grids to substantial shares in many countries. However, this rapid growth has exposed a fundamental challenge: unlike fossil fuel plants that generate electricity on demand, renewable sources produce power intermittently, dependent on weather conditions and time of day. Developing effective, economical energy storage solutions has emerged as the critical obstacle to achieving fully renewable electricity systems.

B Battery technology currently dominates discussions of grid-scale energy storage. Lithium-ion batteries, refined through decades of development for consumer electronics and electric vehicles, offer high energy density, declining costs, and proven reliability. Large battery installations can respond to grid demands within milliseconds, providing valuable services for frequency regulation and short-term supply smoothing. However, lithium-ion technology faces significant limitations for long-duration storage. Batteries sized to power a city through multiple days of unfavourable weather would require enormous capital investment and vast quantities of materials whose supply chains raise environmental and geopolitical concerns. Most grid batteries currently provide storage measured in hours rather than days or weeks.

C Pumped hydroelectric storage represents the most established large-scale storage technology, accounting for approximately 95% of global grid storage capacity. These facilities pump water uphill to elevated reservoirs when electricity is abundant and cheap, then release it through turbines to generate power when demand or prices rise. Pumped hydro installations can store enormous quantities of energy for extended periods and operate efficiently for decades with minimal degradation. Nevertheless, geographical constraints severely limit expansion potential. Suitable sites require specific topography—elevated locations near lower water bodies—and face environmental opposition due to land use impacts. Most promising locations in developed countries have already been utilised.

D Compressed air energy storage offers another mechanical approach to grid-scale storage. These systems use surplus electricity to compress air into underground caverns or purpose-built tanks, then release the pressurized air through turbines when power is needed. Two commercial-scale compressed air facilities have operated for decades, demonstrating technical feasibility. Advanced designs incorporating heat recovery promise significantly improved efficiency compared to earlier installations. However, suitable geological formations for underground storage exist only in limited locations, and above-ground tank systems sacrifice the cost advantages of natural caverns. Research continues into isothermal compression techniques that could improve performance and expand deployment options.

E Hydrogen has attracted considerable attention as a potential storage medium, particularly for seasonal and long-duration applications. Electrolysis uses electricity to split water into hydrogen and oxygen; the hydrogen can then be stored in tanks, underground caverns, or existing natural gas infrastructure before being converted back to electricity through fuel cells or combustion turbines. Hydrogen storage offers effectively unlimited duration—the gas remains stable indefinitely if properly contained—and can leverage existing infrastructure designed for natural gas. Proponents envision hydrogen enabling seasonal storage, capturing summer solar surplus for winter heating demand. Critics note that round-trip efficiency remains poor, with substantial energy lost in conversion processes, and that hydrogen infrastructure requires significant investment to develop.

F Emerging technologies promise to expand storage options further. Flow batteries, which store energy in liquid electrolytes contained in external tanks, can scale storage duration simply by increasing tank size, potentially offering advantages for longer-duration applications. Gravity-based systems, including proposals to raise massive weights in mine shafts or specially constructed towers, offer mechanical simplicity and use abundant materials. Thermal storage captures energy as heat in materials like molten salt, rocks, or sand, providing low-cost storage particularly well-suited for industrial heat applications. Each approach presents distinct trade-offs between cost, efficiency, duration, scalability, and geographic flexibility.

G The optimal storage portfolio for any electricity grid will likely combine multiple technologies matched to specific requirements. Short-duration storage for frequency regulation and daily cycling may continue favouring batteries as costs decline. Medium-duration storage spanning hours to days might employ various mechanical and electrochemical options depending on local geography and economics. Seasonal storage enabling year-round renewable electricity may ultimately require hydrogen or other chemical storage despite efficiency penalties. Policy frameworks supporting storage deployment, research investment accelerating technological development, and electricity market designs properly valuing storage services will all influence how rapidly effective storage solutions emerge to complete the renewable energy transition.

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Questions 14–20

The passage has seven paragraphs, A–G.

Choose the correct heading for paragraphs A–G from the list of headings below.

Write the correct number, i–xi, in boxes 14–20 on your answer sheet.

List of Headings

14 Paragraph A {{ANSWER:14}}

15 Paragraph B {{ANSWER:15}}

16 Paragraph C {{ANSWER:16}}

17 Paragraph D {{ANSWER:17}}

18 Paragraph E {{ANSWER:18}}

19 Paragraph F {{ANSWER:19}}

20 Paragraph G {{ANSWER:20}}

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Questions 21–24

Complete the sentences below.

Choose NO MORE THAN TWO WORDS from the passage for each answer.

Write your answers in boxes 21–24 on your answer sheet.

21 Lithium-ion batteries can respond to changes in grid requirements within {{ANSWER:21}}.

22 Pumped hydroelectric storage currently accounts for roughly {{ANSWER:22}} of worldwide grid storage capacity.

23 Hydrogen produced through electrolysis can potentially be stored in existing {{ANSWER:23}} infrastructure.

24 Flow batteries store energy in {{ANSWER:24}} kept in external tanks.

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Questions 25–26

Choose the correct letter, A, B, C or D.

Write the correct letter in boxes 25–26 on your answer sheet.

25 According to the passage, what is a major disadvantage of hydrogen as an energy storage medium? {{ANSWER:25}}

A      Hydrogen gas degrades quickly when stored.

B      Significant energy is lost during conversion processes.

C      Hydrogen cannot be used for heating applications.

D      The technology has not been tested at commercial scale.

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26 The writer suggests that future grid storage systems will most likely {{ANSWER:26}}

A      rely exclusively on battery technology.

B      use a single dominant storage technology.

C      incorporate various technologies for different purposes.

D      abandon mechanical storage methods entirely.

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SECTION 3: Questions 27–40

Read the passage below and answer Questions 27–40.

The Paradox of Choice in Modern Consumer Society

The contemporary marketplace offers consumers unprecedented variety. Supermarket shelves display dozens of options for products that once came in single versions. Online retailers provide access to millions of items from global suppliers. Streaming services offer catalogues of thousands of films and programmes. This abundance of choice is typically celebrated as empowering consumers, enabling individuals to find products precisely matching their preferences and needs. However, a growing body of psychological research suggests that excessive choice may paradoxically undermine satisfaction, complicate decision-making, and diminish overall wellbeing.

The foundational research challenging assumptions about choice benefits emerged from studies conducted by psychologist Sheena Iyengar and colleagues in the early 2000s. In a now-famous experiment conducted at an upscale grocery store, researchers alternated between displaying six varieties of jam and twenty-four varieties. While the larger display attracted more initial attention from shoppers, actual purchasing behaviour revealed a striking reversal: consumers encountering the limited selection proved ten times more likely to make a purchase than those facing the extensive assortment. Subsequent studies replicated this pattern across diverse contexts, from chocolate selections to retirement investment options, suggesting that choice overload represents a genuine psychological phenomenon rather than a methodological artefact.

Several mechanisms appear to underlie the negative consequences of excessive choice. Decision difficulty increases substantially as options multiply, requiring greater cognitive effort to evaluate alternatives and reach conclusions. This effort proves exhausting, particularly when choices involve significant consequences or require comparing options across multiple attributes. Anticipated regret intensifies with expanded choice sets; selecting from numerous alternatives makes salient the many rejected options, fostering concern that a better choice existed among those not selected. Opportunity costs become more vivid when attractive alternatives must be foregone. Perhaps most significantly, responsibility for outcomes shifts entirely to the chooser when extensive options exist—poor outcomes cannot be attributed to limited availability but must reflect personal choice failure.

The consequences of choice overload extend beyond immediate purchasing decisions to affect broader patterns of satisfaction and engagement. Maximizers—individuals who persistently seek the optimal choice across decisions—report lower life satisfaction and higher depression rates than satisficers, who accept options meeting their requirements without exhaustive comparison. Research in consumer behaviour has documented that satisfaction with chosen products often decreases as the number of rejected alternatives increases, even when the selected item objectively meets or exceeds needs. In contexts ranging from career decisions to romantic partner selection, excessive options appear to promote dissatisfaction and second-guessing rather than contentment with selected outcomes.

Critics of choice overload research have raised methodological concerns and identified boundary conditions limiting the phenomenon's scope. Some replication attempts have failed to reproduce the original jam study findings, prompting debate about effect sizes and contextual factors. Research suggests that expertise moderates choice overload effects; individuals with well-defined preferences and domain knowledge often navigate extensive options effectively. Choice architecture—how options are organised, categorized, and presented—substantially influences whether abundance helps or hinders decisions. Additionally, some scholars argue that laboratory studies poorly reflect real-world conditions where consumers develop strategies for managing complexity and can defer or delegate difficult decisions.

The practical implications of choice research have influenced fields from marketing to public policy. Retailers have experimented with curated selections and recommendation systems designed to reduce overwhelming variety while preserving consumer agency. The "nudge" approach to policy design, developed by behavioural economists Richard Thaler and Cass Sunstein, explicitly addresses choice architecture, advocating default options and simplified comparisons that guide decisions without restricting freedom. Healthcare reformers have applied these insights to insurance marketplace design, recognising that bewildered consumers facing dozens of complex options may make poor choices or avoid choosing altogether. Technology companies have invested heavily in algorithmic recommendation systems that promise to filter overwhelming catalogues to manageable, personalised selections.

The philosophical dimensions of choice abundance merit consideration alongside psychological findings. Liberal democratic societies have traditionally valued autonomy and self-determination, celebrating expanded choice as enhancing freedom. Yet the psychological costs of excessive options complicate this straightforward equation. Freedom from choice—the relief of having decisions made by circumstance, tradition, or authority—may sometimes serve wellbeing better than freedom of choice among overwhelming alternatives. The sociologist Barry Schwartz, synthesising research on choice and wellbeing, provocatively argues that contemporary abundance has created a "tyranny of choice" that leaves individuals less satisfied despite unprecedented material options. Whether this represents an unavoidable consequence of affluence or a challenge addressable through institutional design remains actively debated among researchers and policymakers seeking to promote human flourishing in consumer societies.

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Questions 27–32

Do the following statements agree with the claims of the writer in the passage?

In boxes 27–32 on your answer sheet, write

27 The abundance of consumer choice is universally beneficial for individual wellbeing. {{ANSWER:27}}

28 In Iyengar's jam study, the larger display attracted more shoppers but resulted in fewer purchases. {{ANSWER:28}}

29 Maximizers generally report higher life satisfaction than satisficers. {{ANSWER:29}}

30 All attempts to replicate the original jam study have successfully confirmed its findings. {{ANSWER:30}}

31 People with expertise in a particular area may handle extensive choices more effectively. {{ANSWER:31}}

32 Barry Schwartz believes that abundant choice has made people less satisfied overall. {{ANSWER:32}}

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Questions 33–37

Complete the summary below.

Choose NO MORE THAN THREE WORDS from the passage for each answer.

Write your answers in boxes 33–37 on your answer sheet.

The Psychology of Choice Overload

Research has identified several reasons why too many choices can be problematic. When options increase, {{ANSWER:33}} grows significantly, requiring more mental effort. People also experience greater {{ANSWER:34}} because they worry about missing better alternatives they did not select. Furthermore, when many options are available, individuals must accept full {{ANSWER:35}} if their choice proves disappointing, since limited availability cannot be blamed. These effects have practical consequences: some businesses now use {{ANSWER:36}} to help shoppers navigate large product catalogues. In healthcare, reformers have applied these findings to {{ANSWER:37}} design to help consumers make better decisions.

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Questions 38–40

Choose the correct letter, A, B, C or D.

Write the correct letter in boxes 38–40 on your answer sheet.

38 What point does the writer make about satisfaction with purchased products? {{ANSWER:38}}

A      Satisfaction increases proportionally with the number of available options.

B      Consumers are more satisfied when they choose from smaller selections.

C      Product quality is the only factor determining consumer satisfaction.

D      Satisfaction may decrease as rejected alternatives increase, regardless of product quality.

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39 The writer mentions the "nudge" approach primarily to {{ANSWER:39}}

A      criticise government interference in consumer decisions.

B      illustrate how choice research has influenced policy design.

C      argue that all consumer choices should be made by authorities.

D      demonstrate that behavioural economics has no practical applications.

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40 What is the writer's main purpose in the final paragraph? {{ANSWER:40}}

A      To argue that consumer choice should be eliminated entirely.

B      To suggest that traditional societies were superior to modern ones.

C      To explore the tension between choice abundance and human wellbeing.

D      To prove that all psychological research on choice is flawed.

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— END OF TEST —