2024 Cambridge IGCSE Geography (0460) 模擬試題連答案詳解

(a) (i) Country Y aged 0-4: \(9.0\% + 8.5\% = 17.5\%\).

(ii) Country X has a much higher percentage of elderly dependents than Country Y. In Country X, the total is \(25.0\%\) (\(11.2\% + 13.8\%\)), whereas in Country Y, it is only \(4.0\%\) (\(1.8\% + 2.2\%\)).

(iii) 1. A narrow base (low percentage of 0-4 year olds at \(4.1\%\)) indicates low birth rates.
2. A wide top/apex (high percentage of 65+ at \(25.0\%\)) indicates high life expectancy.
3. A bulge in the middle/working-age cohorts indicates declining birth rates over time and low infant mortality.

(iv) In Stage 2, the pyramid has a very wide base due to high birth rates, and rapidly tapering/concave sides due to high death rates. As the country moves to Stage 4, birth rates fall, causing the base of the pyramid to narrow. Simultaneously, death rates fall and life expectancy increases, meaning more people survive into older cohorts, causing the sides of the pyramid to become straighter and the top of the pyramid to widen/grow taller.

(b) (i) High birth rates in LEDCs occur because:
- There is a lack of availability/knowledge of contraception and family planning.
- High infant mortality rates mean parents have extra children to ensure some survive to adulthood.
- Children are seen as an economic asset to work on agricultural land and bring in income.
- Children are needed to look after parents in old age due to a lack of government pensions.
- Cultural or religious values encourage large family sizes.

(ii) Taking Japan or Germany as an example:
- High cost of providing state pensions puts financial pressure on the working population and government budgets.
- Increased strain on healthcare services and social care systems to treat chronic/elderly diseases.
- Severe labour shortages, meaning there are fewer active workers, leading to economic stagnation.
- Closure of schools and services aimed at young people as resources are diverted to elderly care homes.
- Increase in the dependency ratio, requiring a smaller tax-paying base to support a larger dependent generation.

(a) (i) Award 1 mark for correct calculation:
- \(17.5\%\) (must include % or units if specified, accept 17.5)

(ii) Award up to 2 marks:
- 1 mark for describing the difference (e.g., Country X has a higher proportion of elderly dependents than Country Y / Country Y has fewer elderly dependents).
- 1 mark for using correct comparative figures (e.g., Country X has \(25\%\) elderly while Country Y has \(4\%\)).

(iii) Award up to 3 marks for identifying features of Country X:
- Narrow base / small percentage of children (accept \(4.1\%\)) indicating low birth rate.
- Wide apex / high percentage of over 65s (accept \(25\%\)) indicating low death rate / long life expectancy.
- Bulge in middle / majority of population in middle working age groups.

(iv) Award up to 4 marks (1 mark for each point explaining changes):
- Base narrows / shrinks as birth rates fall (1 mark).
- Top becomes wider / taller as life expectancy increases (1 mark).
- Sides become straighter / more vertical as death rates fall (1 mark).
- Overall shape changes from triangular/pyramid shape to a barrel/beehive/rectangular shape (1 mark).

(b) (i) Award up to 3 marks for explaining high birth rates (1 mark per distinct reason):
- Lack of contraception / family planning clinics (1 mark).
- Need for child agricultural labour (1 mark).
- High infant mortality rates mean parents have more children (1 mark).
- Children act as pension / security for old age (1 mark).
- Traditional / religious opposition to family planning (1 mark).
- Early marriage / childbearing ages (1 mark).

(ii) Award up to 5 marks (max 4 marks if no named country/case study context is given):
- 1 mark for naming a relevant country (e.g., Japan, Italy, Germany).
- Up to 4 marks for explaining challenges (1 mark per point / well-developed idea):
- Government spends more on pensions, diverting funds from other sectors (1 mark).
- Pressure on hospitals / geriatric services due to age-related illnesses (1 mark).
- Shortage of labor / workforce leads to economic decline (1 mark).
- Tax revenues fall as fewer people are working (1 mark).
- Need for increased nursing homes / elderly care workers (1 mark).
- Decline of services for the young, e.g., school closures (1 mark).

Case Study: Namibia
Namibia is one of the most sparsely populated countries in the world, with an average population density of around 3 people per square kilometer.

Physical Causes:
1. Climate: A vast proportion of Namibia is covered by the hyper-arid Namib Desert along the west coast and the semi-arid Kalahari Desert to the east. These regions experience extremely low and unpredictable rainfall, with coastal desert areas receiving less than 50 mm annually. This hyper-aridity makes arable farming virtually impossible.
2. Temperature and Soils: Extreme daytime temperatures often exceeding 40 degrees Celsius lead to very high evapotranspiration rates, drying out any moisture. The sandy and rocky desert soils lack organic nutrients, preventing productive agriculture and subsistence farming.
3. Water Supply: The country has no permanent inland perennial rivers; major rivers like the Kunene and Orange are only found on its northern and southern borders, leaving the vast interior dependent on scarce groundwater aquifers.

Human Causes:
1. Infrastructure: Due to the immense distances between habitable areas, building and maintaining transport infrastructure like paved roads and railways is extremely expensive. This leaves many rural settlements highly isolated and disconnected from national markets.
2. Economic Opportunities: Employment is heavily concentrated in a few urban centers, such as the capital Windhoek and the port of Walvis Bay. Outside of these cities and a few mining hubs (like uranium mining in the Erongo region), there are very few secondary or tertiary jobs, driving younger populations to migrate away and leaving vast rural areas virtually empty.

Level 1 (1 to 3 marks):
- Identifies simple physical or human factors with generalized statements (e.g., it is a desert, it is hot, there are no jobs, there is no water).
- No specific case study selected, or a highly inappropriate case study.

Level 2 (4 to 6 marks):
- Explains physical and/or human factors with some geographical development (e.g., lack of rainfall means crops cannot grow, leading to a lack of food and water; lack of roads makes it hard for people to travel to work or access services).
- Maximum 5 marks if there is no named case study or if no place-specific details are included.

Level 3 (7 marks):
- Comprehensive and well-developed explanation of both physical and human factors.
- Includes specific, accurate place-specific details and/or statistical data for the chosen case study (e.g., naming Namibia, Namib Desert, Kalahari, Windhoek, Walvis Bay, referencing rainfall less than 50 mm, or temperatures exceeding 40 degrees Celsius).

(a) (i)
- Slip-off slope (or point bar).

(a) (ii)
- At Point A, the river bed is shallow and forms a gentle slope / slip-off slope.
- At Point B, the river bed is much deeper and features a steep-sided river cliff.

(a) (iii)
- At Point A, the water velocity is slow (due to friction with the inner bank), which reduces the river's energy, leading to the deposition of sediment.
- At Point B, the water velocity is fast (thalweg / centrifugal force), giving the river high kinetic energy, which leads to active lateral erosion (by hydraulic action and abrasion/corrasion).

(a) (iv)
- Lateral erosion occurs on the outer banks of the meander, while deposition occurs on the inner banks.
- This continuous process narrows the neck of the land between the meander loop.
- During a period of high discharge (such as a flood), the river takes the shortest, straightest path and cuts directly through the narrow neck.
- The main flow of the river now bypasses the old meander loop.
- Deposition of silt and sediment occurs at the ends of the abandoned loop, sealing it off and leaving a crescent-shaped oxbow lake.

(b) (i)
- Heavy or prolonged rainfall (increases surface runoff once soil is saturated).
- Steep valley slopes (accelerates surface runoff into the river channel).
- Impermeable geology/rocks, such as clay or granite (prevents infiltration, increasing overland flow).
- Saturated antecedent soil conditions from previous rain events.
- Rapid snowmelt.

(b) (ii)
- Deforestation: Removing trees reduces interception of rainfall and transpiration, leading to rapid water movement over the land surface into the river.
- Urbanisation: Covering soil with impermeable tarmac and concrete prevents infiltration, leading to high surface runoff.
- Artificial drainage: Storm drains and gutters quickly route rainwater directly to the river channel, shortening the lag time.
- Soil compaction (from intensive agriculture or heavy machinery): Reduces the soil's infiltration capacity, causing more overland flow.
- Channelisation: Straightening or concrete-lining rivers can speed up the flow, transferring the flood risk rapidly to areas downstream.

(a) (i) [1 mark]
- 1 mark for identifying slip-off slope or point bar.

(a) (ii) [2 marks]
- 1 mark for describing Point A (shallow/gently sloping).
- 1 mark for describing Point B (deep/steep/river cliff).
- Note: Must compare both points to receive full marks.

(a) (iii) [3 marks]
- 1 mark for linking slow velocity at Point A to low energy and deposition.
- 1 mark for linking fast velocity at Point B to high energy and erosion.
- 1 mark for identifying a specific erosion process (e.g., hydraulic action, abrasion/corrasion) or referencing the thalweg/centrifugal force.

(a) (iv) [4 marks]
- 1 mark for explaining that lateral erosion narrows the meander neck.
- 1 mark for explaining that the river cuts through the neck during high flow/flood.
- 1 mark for explaining that the river flow takes the shortest/straightest path.
- 1 mark for explaining that deposition seals off the old meander loop to form the oxbow lake.

(b) (i) [3 marks]
- 3 marks for describing three physical factors (1 mark per factor):
* Heavy/prolonged rainfall
* Steep slopes/valley sides
* Impermeable rock types (e.g., granite, clay)
* Prior saturation of soil (antecedent rainfall)
* Sudden snowmelt

(b) (ii) [5 marks]
- 5 marks for explaining human impacts, with up to 2 marks per developed point:
* Deforestation (1) reduces interception/transpiration (1) resulting in faster runoff (1).
* Urbanisation/concrete surfaces (1) are impermeable and prevent infiltration (1).
* Artificial drains/gutters (1) transport water rapidly to rivers, shortening lag times (1).
* Agriculture/ploughing downslope or soil compaction (1) reduces infiltration and increases surface runoff (1).

Exemplar Case Study: Ganges and Brahmaputra Rivers, Bangladesh

Physical Causes:
- Heavy Monsoon Rains: Bangladesh experiences intense monsoon rainfall from June to September, with some areas receiving over 2000mm of rain. This saturates the soil and drastically increases river discharge.
- Himalayan Meltwater: Global warming and seasonal spring temperature increases accelerate the melting of glaciers in the Himalayas, swelling the headwaters of the Ganges and Brahmaputra rivers.
- Low-lying Topography: Over 80% of Bangladesh lies on a flat, low-lying delta floodplain (less than 10 meters above sea level), making it physically difficult for floodwaters to drain away quickly.
- Peak Discharge Convergence: The peak discharges of the Ganges and Brahmaputra rivers can occur at similar times, overwhelming the main channel capacities.

Human Causes:
- Deforestation in the Upper Catchment: Intensive logging on the steep slopes of the Himalayas in Nepal and India has reduced interception and evapotranspiration. This leads to rapid overland flow and soil erosion, which silts up riverbeds in Bangladesh, lowering their carrying capacity.
- Rapid Urbanisation: The rapid expansion of cities like Dhaka has increased impermeable concrete surfaces. This prevents infiltration, increases surface runoff, and overloads the local drainage and river channels.
- Soil Erosion and Siltation: Poor agricultural practices and deforestation lead to high silt loads. As the river slows down in the flat delta, it deposits sediment on the riverbeds, raising the riverbed and decreasing the volume of water the channel can safely hold before overflowing.

Level 1 (1–3 marks):
- Simple, descriptive statements that identify physical and/or human causes of flooding.
- Little or no explanation of the processes involved.
- Focuses on general points with no specific place-specific details.
- E.g., 'Heavy rain makes the river overflow.' 'People cut down trees so water gets to the river faster.'

Level 2 (4–6 marks):
- Explains the physical and/or human causes of flooding with clear geographical reasoning (e.g., links deforestation to reduced interception and increased overland flow, or links monsoon rains to saturated soil and rapid surface runoff).
- To achieve the top of Level 2 (6 marks), both physical and human causes must be explained clearly.
- E.g., 'Monsoon rains quickly saturate the soil in the catchment area, meaning no more water can infiltrate, leading to rapid surface runoff. Deforestation on the slopes of the Himalayas reduces interception, which increases the speed and volume of water entering the river tributaries.'

Level 3 (7 marks):
- Comprehensive and well-developed explanation of BOTH physical and human causes of flooding.
- Must include place-specific details (e.g., named locations, specific quantities, river names, or country-specific context) for a named river basin or country (such as the Ganges/Brahmaputra in Bangladesh or River Severn in the UK).

(a)(i) 18%. (a)(ii) There is a negative correlation; as GNI per capita increases, agricultural employment decreases. For example, Country A has a GNI per capita of $550 and 72% agricultural employment, while Country H has $58,000 GNI per capita and 2% agricultural employment. (a)(iii) 1. Farming is mainly subsistence-based so many families must farm to feed themselves. 2. Lack of machinery and agricultural technology means tasks are labour-intensive. 3. Lack of alternative secondary/tertiary jobs due to limited industrial development. (a)(iv) 1. GNI per capita is an average that hides wealth inequalities between rich and poor. 2. It ignores the informal economy and subsistence farming which are major in LEDCs. 3. It does not measure social indicators such as healthcare, education, or life expectancy. 4. Currency exchange rate fluctuations can distort comparisons. (b)(i) As development occurs, employment in the primary sector decreases. The secondary sector initially grows during industrialisation and then declines. The tertiary and quaternary sectors grow steadily and become dominant. (b)(ii) For China: 1. TNCs brought Foreign Direct Investment (FDI) to build manufacturing plants in Special Economic Zones. 2. This created millions of jobs, raising incomes and creating a positive multiplier effect. 3. Workers gained technical and managerial skills. 4. Greater tax revenues allowed the government to invest in infrastructure like high-speed rail and ports.

Part (a)(i) [1 mark]: Award 1 mark for stating 18%. Part (a)(ii) [2 marks]: Award 1 mark for identifying the negative/inverse relationship (as GNI per capita rises, agricultural employment falls). Award 1 mark for correct use of data from Figure 1 supporting this trend (must state two GNI values and corresponding percentages). Part (a)(iii) [3 marks]: Award 1 mark per valid reason up to 3: subsistence farming dominance; lack of machinery/heavy manual labor reliance; lack of alternative jobs in industry/services; lack of capital to start business. Part (a)(iv) [4 marks]: Award 1 mark per valid limitation explained up to 4: it is an average that hides inequality; misses informal sector transactions; ignores social factors (health, education); distorted by exchange rates; ignores regional differences. Part (b)(i) [3 marks]: Award up to 3 marks for describing structural shifts: primary sector declines (1); secondary sector increases then decreases (1); tertiary/quaternary sectors increase and dominate (1). Part (b)(ii) [5 marks]: Award 1 mark for naming a valid country/area (e.g., China). Award up to 4 marks for explaining how TNCs/globalisation contributed to development: TNC investment (FDI) (1); job creation raising household incomes (1); training/skills transfer (1); infrastructure improvements (1); multiplier effect boosting local suppliers (1); increased tax revenues for government (1).

To achieve a Level 3 (7 marks), candidates must provide a comprehensive answer that describes and explains at least two renewable energy sources with place-specific details (such as named locations, power stations, or specific statistics) from a chosen country (e.g., Iceland).

**Example Case Study: Iceland**

* **Geothermal Energy (Description & Explanation):** Iceland uses geothermal energy for electricity and district heating. This is possible because it lies on the active constructive plate boundary of the Mid-Atlantic Ridge, bringing magma close to the crust to heat groundwater. The Hellisheidi Power Station is a key site producing over 300 MW of electricity.
* **Hydroelectric Power (Description & Explanation):** HEP provides nearly 73% of the country's electricity. The steep, mountainous landscape and high glacial runoff (e.g., from Vatnajökull) create fast-flowing, high-volume rivers. The Kárahnjúkar HEP plant was constructed to harness this energy, supplying power to the Alcoa aluminium smelter, demonstrating its industrial utility.

**Level 1 (1–3 marks):**
* Simple, generic statements describing or explaining renewable energy (e.g., 'They use wind power because it is windy' or 'They use dams to make electricity from rivers').
* No specific country context or very vague location detail.

**Level 2 (4–6 marks):**
* More detailed, explained statements that show a clear understanding of how and why the energy is developed (e.g., 'In Iceland, geothermal energy is used because they are on a plate boundary where heat is close to the surface' or 'Glacial rivers are dammed to produce HEP because there is lots of fast-flowing water').
* At the upper end of this level (6 marks), there must be some appropriate place-specific detail (e.g., named plants, rivers, or statistics).

**Level 3 (7 marks):**
* Comprehensive and detailed explanations of at least two renewable energy sources.
* Includes precise, accurate, and named place-specific details (e.g., Hellisheidi, Kárahnjúkar, Mid-Atlantic Ridge, Vatnajökull) supporting both the description and the explanation.

Part (a): (i) To find the six-figure grid reference, look at the easting line 24 and estimate tenths across to the church tower (3 tenths), giving 243. Then look at the northing line 45 and estimate tenths up (2 tenths), giving 452. Combine these to get 243452. (ii) Grid reference 284416 points to the symbol for a Quarry on the map. (iii) Following the course of the River Glen through square 2845 shows it flows from the bottom-left toward the top-right, which is South-west to North-east. Part (b): (i) Using a ruler to measure between the two points, the physical map distance corresponds to 8.2 km on the scale bar (allowable range 8.0 to 8.4 km). (ii) Aligning a protractor from the post office (center point) towards the viewpoint gives a bearing of 56 degrees (allowable range 54 to 58 degrees). Part (c): The settlement pattern shows a high concentration (nucleation) in the south-west flat basin (Glenwood town). Linear settlements follow the primary transport route (the A4105 road) in the valley. High-elevation slopes and the north-west forest are mostly empty, with only isolated, dispersed farmsteads. The active floodplain is avoided due to flood risks. Part (d): (i) Count up the contour lines from the index contour (200m) to the next line on the flat ridge, which is 210m. (ii) The relief north of northing 48 is characterized by rugged, steep terrain in the north-west (indicated by closely spaced contours), a high, flat plateau/ridge in the north-east exceeding 200m, and a steep north-south valley carved by stream action. (iii) The river features a meandering course with active bends, an oxbow lake (cutoff) indicative of mature river processes, a broad and flat valley floor (floodplain), and lateral tributaries flowing down from the valley sides.

Part (a) [4 marks total]: (i) 2 marks for 243452 (1 mark for correct grid square 2445; 1 mark for correct tenths: 242-244 and 451-453). (ii) 1 mark for Quarry (Accept: active quarry, open-cast mine). (iii) 1 mark for South-west to North-east (Accept: NE, North-easterly). Part (b) [4 marks total]: (i) 2 marks for 8.2 km (1 mark for 8.0 to 8.4 km; 2 marks for exact 8.2 km). (ii) 2 marks for 56 degrees (1 mark for 54 to 58 degrees; 2 marks for exact 56 degrees). Part (c) [5 marks total]: Max 5 marks for points describing settlement distribution: - Nucleated / clustered in the south-west / Glenwood town (1 mark) - Linear along the A4105 road / valley floor (1 mark) - Dispersed / scattered farmsteads in the uplands / hills (1 mark) - Absent / sparse on steep slopes / high land above 150m (1 mark) - Absent / avoided on the river floodplain (1 mark) - Sparse in forested areas (1 mark). Part (d) [7 marks total]: (i) 1 mark for 210m. (ii) Max 3 marks for describing northern relief: - Steep slopes in the north-west (1 mark) - Flat plateau / ridge / gentle slopes in the north-east (1 mark) - Valley / deep valley running north-south (1 mark) - High land / altitude over 240m (1 mark). (iii) Max 3 marks for physical river/valley features: - Meanders / winding river (1 mark) - Oxbow lake / cutoff (1 mark) - Broad / wide / flat valley floor / floodplain (1 mark) - Tributaries / confluences (1 mark).

(a) Annual temperature range is calculated as the maximum monthly temperature minus the minimum monthly temperature: \(27^\circ\text{C} - 26^\circ\text{C} = 1^\circ\text{C}\).

(b) Looking at the rainfall data, July has the lowest value of 80 mm.

(c) Total annual rainfall is the sum of all monthly rainfall: \(250 + 240 + 280 + 220 + 180 + 110 + 80 + 90 + 120 + 160 + 200 + 230 = 2160\text{ mm}\).

(d) The climate shown is a Tropical Rainforest climate. Typical vegetation characteristics include: evergreen broadleaf trees, shallow but wide buttress roots for stability, distinct stratified layers (canopy, undercanopy, shrub layer), leaves with waxy coatings and drip-tips to shed excess rainwater rapidly, and climbing plants like lianas.

(e) Intense solar radiation (insolation) near the equator heats the ground. The air above the ground becomes hot, absorbs moisture from high evapotranspiration, and rises rapidly. As this warm air rises, it cools at the adiabatic lapse rate, reaches its dew point, and water vapor condenses into towering cumulus/cumulonimbus clouds, releasing heavy convectional rain.

(a) 1 mark for correct temperature range: 1°C (units must be included).

(b) 1 mark for identifying both the month and the value: July AND 80 mm (accept 80 without mm if month is correct, but reject if wrong month).

(c) 2 marks total:
- 1 mark for correct calculation method (summing up all 12 values: \(250 + 240 + \dots\)).
- 1 mark for the correct total: 2160 mm (allow 2160 without units).

(d) 2 marks (1 mark per valid characteristic) such as:
- Evergreen nature / trees do not lose leaves at the same time
- Drip-tips
- Buttress roots
- Canopy / stratification / layers
- Large / broad leaves
- Lianas / epiphytes

(e) 2 marks (1 mark per valid explanation point) such as:
- High solar radiation / high temperatures lead to high rates of evaporation / evapotranspiration (1)
- Air rises / convection currents form (1)
- Air cools and condenses / forms cumulonimbus clouds (1)
- Heavy afternoon storms / convective storms occur (1)

(a) (i) A wide base on a population pyramid indicates a high birth rate/high proportion of young children.
(ii) High birth rates in developing countries (Country A) are typically caused by a lack of access to family planning/contraception, high infant mortality rates (leading parents to have more children to ensure some survive), traditional cultural preferences for large families, or the need for manual agricultural labor.

(b) Country B has an ageing population structure where the elderly dependents (20%) exceed the young dependents (15%), showing a low birth rate and high life expectancy. The economically active age group makes up the largest segment (65%).

(c) An ageing population structure poses several socio-economic risks, including: high healthcare costs due to age-related illnesses; strain on public funds to pay for pensions; labor shortages in the economy; a rising dependency ratio putting pressure on tax-paying workers.

(d) The dependency ratio is calculated using the formula:
\(\text{Dependency Ratio} = \frac{\text{Young Dependents (under 15)} + \text{Elderly Dependents (65+)}}{\text{Economically Active (15-64)}} \times 100\)

\(\text{Dependency Ratio} = \frac{15 + 20}{65} \times 100 = \frac{35}{65} \times 100 \approx 53.846\%\).
Rounded to one decimal place, this is 53.8.

(a) (i) 1 mark for: High birth rate / high proportion of children.
(ii) 1 mark for any valid reason for a high birth rate, such as:
- Lack of family planning / contraception / sex education (1)
- High infant mortality (so families have more children) (1)
- Children are needed to work on farms / earn income (1)
- Religious / cultural beliefs against birth control (1)
- Traditional preference for large families (1)

(b) 2 marks total:
- 1 mark for noting the relatively low percentage of young dependents (15%) / high elderly population (20%) / indicating an ageing population (1).
- 1 mark for noting that nearly two-thirds / the majority (65%) are of working age (1).

(c) 2 marks (1 mark per challenge) such as:
- High cost of medical care / strain on hospitals (1)
- High cost of state pensions / financial burden on government (1)
- Shortage of labor / lack of young workers to fill jobs (1)
- Increased tax burden on the working-age population (1)
- Need for specialized eldercare facilities / care homes (1)

(d) 2 marks total:
- 1 mark for correct working showing addition of dependents and division by economically active: \(\frac{15 + 20}{65} \times 100\) or \(\frac{35}{65} \times 100\).
- 1 mark for correct final value: 53.8 (accept 54 if rounded to whole number, but 53.8 is the exact single decimal place answer; reject 53).

(a) City Q is urbanising most rapidly because it has the highest average annual growth rate (4.8% per year), and its urban population more than tripled over the 30-year period.

(b) The calculation is \(78\% - 45\% = 33\%\).

(c) (i) Informal settlements are typically characterized by poorly constructed, temporary housing (using scrap materials like corrugated iron, wood, plastic), a lack of basic services (no piped water, sewage systems, or formal grid electricity), very high density/overcrowded living spaces, and location on unsafe marginal land like steep hillsides or marshy floodplains.
(ii) Rural push factors are negative aspects of rural life driving people away, such as lack of jobs, poor agricultural productivity/drought/crop failure, poor schools, lack of hospitals, or conflict.

(d) Self-help schemes are programs where local authorities support residents in upgrading their own living environments. Examples include "site and service" schemes, where the government lays out a grid of plots with sewage, clean water, and electricity, and residents construct their houses on these prepared sites. Another method is granting legal land ownership/tenure, which motivates residents to invest their own money into improving their homes without fear of eviction. Other actions include providing low-interest loans or building materials.

(a) 1 mark for: City Q.

(b) 1 mark for: 33% (allow 33 without % symbol).

(c) (i) 2 marks (1 mark per valid physical characteristic) such as:
- Homes built of scrap/temporary materials (e.g., corrugated iron, wood, canvas) (1)
- Lack of basic sanitation / no toilets / raw sewage in streets (1)
- Lack of clean piped water / reliance on standpipes or water trucks (1)
- High building density / overcrowded / houses packed tightly together (1)
- Built on hazardous/marginal land (e.g., steep slopes prone to landslides, river floodplains) (1)
- Lack of tarred roads / muddy paths (1)
- Illegal electricity connections / dangerous wiring (1)

(ii) 2 marks (1 mark per push factor) such as:
- Low wages / lack of job opportunities in rural farming (1)
- Drought / crop failure / famine (1)
- Extreme weather / natural disasters (1)
- Poor schools / limited access to education (1)
- Lack of hospitals / clinics / medical care (1)
- War / conflict / persecution (1)

(d) 2 marks (1 mark per described self-help scheme) such as:
- Site and service schemes: council provides land, roads, and basic utilities (water/sewerage) and residents build their own homes (1)
- Low-interest loans or provision of cheap/free construction materials (bricks, timber, cement) (1)
- Giving legal land tenure / deeds to residents so they feel secure enough to invest in house improvements (1)
- Upgrading basic infrastructure, such as installing municipal water standpipes, paving roads, or establishing formal electricity grids (1)

(a) (i) The maximum temperature is read at the base of the metal index on the maximum scale (right side), which is \(28^\circ\text{C}\).
(ii) The minimum temperature is read at the base of the metal index on the minimum scale (left side), which is \(12^\circ\text{C}\).
(iii) The current temperature is read directly at the top of the mercury column in either arm, which is \(19^\circ\text{C}\).

(b) The steel indices inside the glass tubes are reset using a small handheld magnet, which pulls the magnetic metal indices down until they rest on top of the mercury columns.

(c) (i) An anemometer (usually a cup anemometer) is used to measure wind speed.
(ii) A barometer (aneroid or mercury barometer) is used to measure atmospheric pressure.

(d) The Stevenson Screen is raised on legs (usually 1.2 to 1.5 meters high) to ensure that the thermometers are not affected by ground radiation, ground heat, or surface reflections (albedo). It is painted white to reflect solar radiation/heat rather than absorb it, ensuring the air temperature inside is measured accurately in the shade.

(a) (i) 1 mark for: 28°C (allow 28).
(ii) 1 mark for: 12°C (allow 12).
(iii) 1 mark for: 19°C (allow 19).

(b) 1 mark for: Using a magnet to pull/slide the steel indices down (to the top of the mercury meniscus).

(c) (i) 1 mark for: Anemometer.
(ii) 1 mark for: Barometer.

(d) 2 marks total:
- 1 mark for explaining white paint: reflects sunlight / solar radiation / prevents absorption of heat (1).
- 1 mark for explaining raised legs: avoids ground heat / avoids heat radiating from the ground / ensures air temperature is measured at standard height (1).

(a) The trend shows a massive decrease in dissolved oxygen immediately after the factory (dropping from 9.5 mg/L at Station A to a low of 1.8 mg/L at Station B). After Station B, the dissolved oxygen levels steadily recover/rise as the river flows downstream, reaching 4.2 mg/L at 5 km, 7.0 mg/L at 10 km, and returning almost to normal (9.2 mg/L) at 20 km (Station E).

(b) There is a direct/positive relationship. When dissolved oxygen levels are low, the number of fish species is low (e.g., Station B has 1.8 mg/L and only 1 species). As dissolved oxygen levels increase, the diversity of fish species increases (e.g., Station E has 9.2 mg/L and 15 species).

(c) A factory can lower dissolved oxygen levels in two main ways:
1. Eutrophication/Decomposition: discharging organic pollutants which act as nutrients for bacteria. The bacterial population multiplies rapidly and consumes oxygen during respiration.
2. Thermal pollution: releasing hot water used for cooling. Warmer water holds less dissolved gases, including oxygen, causing oxygen levels to drop.

(d) To prevent water pollution, the factory can build on-site waste treatment facilities to neutralize chemicals and filter out organic substances before releasing the water. Governments can set legal limits on effluents and enforce them with regular inspections and high fines. Water can also be recycled in closed-loop systems within the factory.

(e) Other environmental risks of industrial development include: air pollution (release of sulfur dioxide/nitrogen oxides leading to acid rain), greenhouse gas emissions contributing to global warming, noise pollution from machinery, and soil/land pollution from improper hazardous solid waste disposal.

(a) 2 marks total:
- 1 mark for describing the sharp fall between Station A and Station B / immediately downstream of the factory (from 9.5 to 1.8 mg/L) (1).
- 1 mark for describing the gradual recovery/increase as you move further downstream towards Station E (1).

(b) 1 mark for: Positive correlation / relationship / as dissolved oxygen increases, the number of fish species increases (or vice versa).

(c) 2 marks (1 mark per valid explanation point) such as:
- Discharging organic waste stimulates bacterial growth / bacteria multiply (1)
- Bacteria consume dissolved oxygen during respiration / decomposition (1)
- Discharging hot/warm water (thermal pollution) (1)
- Warm water holds less dissolved oxygen than cold water (1)

(d) 2 marks (1 mark per measure) such as:
- Treating industrial effluent / sewage in a wastewater treatment plant before release (1)
- Recycling water inside the factory / closed-loop cooling system (1)
- Government setting strict legal limits on pollution / environmental audits (1)
- Imposing heavy fines / penalties for factories that violate standards (1)
- Regular monitoring of water quality at discharge points (1)

(e) 1 mark for any valid non-water industrial pollution risk, such as:
- Air pollution / smog (1)
- Acid rain / sulfur dioxide emissions (1)
- Global warming / greenhouse gas emissions (1)
- Noise pollution from factory machinery (1)
- Land / soil contamination from toxic dumping (1)
- Deforestation / habitat destruction to build factories (1)

(a) (i) Flow meter method:
1. Submerge the impeller (propeller) completely under the water.
2. Ensure the impeller faces directly upstream into the current.
3. Hold the metal rod vertically at a consistent relative depth (e.g., at 60% of the depth or just below the surface).
4. Take multiple readings at regular intervals along a cross-section transect of the river and calculate the mean velocity.

(a) (ii) Flow meter vs Float:
- Advantage: More accurate because it measures velocity below the surface where friction is different; unaffected by surface wind; gives an immediate digital readout.
- Disadvantage: Expensive equipment; requires batteries which can fail; impeller can get clogged by debris or weeds.

(b) (i) Systematic sampling of pebbles:
1. Stretch a tape measure across the river channel from one bank to the other.
2. Pick pebbles at fixed, regular intervals along the tape (e.g., every 50 cm).
3. To avoid selection bias, pick the pebble that is touched by the fingertip or a ruler when lowering it blindly onto the river bed.

(b) (ii) Sample size:
A sample of 20 pebbles is more representative of the total population of bedload, which reduces the impact of anomalous pebbles and increases the reliability of the average.

(c) Anomaly analysis:
- Anomaly: Site 5 (velocity drops from 0.58 m/s at Site 4 to 0.52 m/s at Site 5).
- Geographical reasons: The river channel may have widened locally, increasing friction and decreasing the hydraulic radius; the local gradient may be flatter (e.g., a pool area); there may be human interference upstream (such as a weir or dam slowing down flow).

(d) Hypothesis 1 Evaluation:
The hypothesis is partially true (or true with an anomaly). Velocity increases from 0.22 m/s at Site 1 (1.5 km downstream) to 0.35 m/s at Site 2 (4.2 km downstream) and reaches a maximum of 0.58 m/s at Site 4 (12.5 km downstream). However, it decreases to 0.52 m/s at Site 5 (18.0 km downstream), indicating that the increase is not continuous.

(e) (i) Percentage Decrease Calculation:
- Initial size (Site 1) = 14.2 cm
- Final size (Site 5) = 2.1 cm
- Decrease = \(14.2\text{ cm} - 2.1\text{ cm} = 12.1\text{ cm}\)
- Percentage Decrease = \(\left(\frac{12.1}{14.2}\right) \times 100 = 85.21\%\) (accept 85% to 85.2%).

(e) (ii) Fluvial processes:
- Attrition: Pebbles collide with one another as they are transported downstream, chipping away sharp corners and reducing overall size.
- Abrasion: Bedload scrapes and grinds against the river bed and banks, wearing away over time.
- Solution: Weak acids in river water dissolve soluble rock types (such as limestone).

(f) Hypothesis 2 Evaluation:
The hypothesis is fully supported. Pebble size continuously decreases downstream: from 14.2 cm at Site 1 (1.5 km) to 7.2 cm at Site 3 (8.0 km), down to 2.1 cm at Site 5 (18.0 km). Concurrently, roundness increases steadily from 1.8 (angular) at Site 1 to 3.1 at Site 3, reaching 5.1 (highly rounded) at Site 5.

(g) Safety precautions:
1. Wear sturdy, non-slip footwear or waders to prevent falls on slippery rocks.
2. Monitor weather forecasts to avoid flash floods; do not enter deep or fast-flowing water (above knee height).
3. Wash hands after fieldwork to prevent waterborne diseases (like Weil's disease).

(a) (i) Max 4 marks: 1 mark for submerging impeller, 1 mark for facing into flow, 1 mark for holding rod vertically/at consistent depth, 1 mark for taking multiple cross-river measurements/averaging.
(a) (ii) Max 2 marks: 1 mark for advantage (e.g. not affected by wind / more accurate), 1 mark for disadvantage (e.g. expensive / weed blockage).
(b) (i) Max 3 marks: 1 mark for laying tape measure bank-to-bank, 1 mark for regular intervals (e.g. every 50cm), 1 mark for non-biased selection technique (touching blind).
(b) (ii) Max 1 mark: more representative sample / reduces anomaly impact / improves reliability.
(c) Max 3 marks: 1 mark for identifying Site 5, up to 2 marks for valid physical/human explanations (e.g., channel widening, gradient change, weir/human management).
(d) Max 4 marks: 1 mark for stating 'partially true', 2 marks for quoting rising velocity data with sites/distances (e.g., 0.22 m/s at Site 1 to 0.58 m/s at Site 4), 1 mark for pointing out the drop at Site 5 (0.52 m/s).
(e) (i) Max 2 marks: 1 mark for correct working, 1 mark for correct answer (85% to 85.21%).
(e) (ii) Max 4 marks: up to 2 marks for defining Attrition clearly, up to 2 marks for Abrasion, Solution, or Hydraulic Action definition in the context of size reduction and rounding.
(f) Max 4 marks: 1 mark for stating 'fully supported', 1 mark for quoting pebble size decrease with data (e.g., Site 1 is 14.2cm, Site 5 is 2.1cm), 1 mark for quoting roundness increase with data (e.g., Site 1 is 1.8, Site 5 is 5.1), 1 mark for linking distance to both trends.
(g) Max 3 marks: 1 mark for each sensible precaution (footwear, depth limits, group work, hygiene, weather checks).

### Worked Solution

**Part (a)**
* (i) The question contains two major flaws: first, it is highly sensitive, subjective, and potentially offensive ("How poor are you?"). Second, it is a leading/biased question ("terrible local infrastructure") which assumes the infrastructure is bad and guides the respondent towards a negative response.
* (ii) Proper ethical research practice requires: 1) Clearly explaining the academic purpose of the study to respondents; 2) Seeking verbal or written informed consent before commencing; 3) Guaranteeing anonymity and confidential treatment of the data collected.
* (iii) Closed questions generate structured, quantitative data. This makes it much easier to categorize, sum, and visually represent (e.g., in bar charts or pie charts) compared to open-ended qualitative text.

**Part (b)**
* (i) To implement systematic sampling: 1) The students should obtain a street map of Westlands; 2) Determine a sampling interval, such as surveying every 5th or 10th household; 3) Walk along a designated route (transect line) and consistently apply this interval to select houses.
* (ii) *Advantage:* Ensures a balanced spatial distribution across the entire suburb, avoiding clustering. *Disadvantage:* Not every household has an equal, non-zero chance of selection (it is non-probability based), meaning it can introduce bias if there is a recurring architectural layout (e.g., corner houses always being selected).
* (iii) A sample of 50 households is far more statistically representative of the wider community than a tiny sample of 10, meaning anomalies (outliers) will have less skewing impact on the final conclusions.

**Part (c)**
* (i) To construct a comparative divided bar graph: 1) Draw two parallel bars of equal length (representing 100% or 50 households each); 2) Subdivide each bar into segments proportional to the frequency of each category (e.g., for Huruma, sections of 3, 25, 15, and 7 units wide); 3) Apply distinctive colors/shading to each category and include a comprehensive key/legend.
* (ii) \(\text{Percentage} = \frac{15}{50} \times 100 = 30\%\).
* (iii) \(\text{Degrees} = \frac{30}{50} \times 360^{\circ} = 0.6 \times 360^{\circ} = 216^{\circ}\).

**Part (d)**
* (i) Hypothesis 1 is fully supported. Quality of life and basic infrastructure are significantly superior in the planned suburb of Westlands compared to Huruma. For example, 96% of households in Westlands (48 out of 50) have piped water direct to their homes, whereas in Huruma, only 6% (3 out of 50) have this luxury. Instead, Huruma households must rely on lower-quality or more costly alternative sources: 50% (25 out of 50) use public kiosks, and 30% (15 out of 50) depend on tanker trucks.
* (ii) Alternative indicators include: 1) Average monthly household income; 2) Literacy rate or average years of schooling; 3) Prevalence of waterborne diseases or distance to the nearest healthcare clinic.
* (iii) *Difficulty 1:* High crime rates or security risks for student researchers. *Mitigation:* Work in groups of 3 or 4, wear high-visibility school vests, and only conduct surveys during peak daylight hours.
* *Difficulty 2:* Narrow, unmapped alleys causing students to get lost. *Mitigation:* Hire a local community guide or seek permission and guidance from the village elder/local administration before entering the area.

**(a)(i)** [2 marks total, 1 mark per identified flaw]:
- Accept: Question is leading / biased / assumes infrastructure is terrible.
- Accept: Question is offensive / too personal / insensitive about poverty levels.
- Accept: It is a double-barrelled question (asks about poverty and infrastructure in one go).

**(a)(ii)** [3 marks total, 1 mark per valid guideline]:
- Accept: Introduce themselves and explain the academic purpose of the study.
- Accept: Ask for consent / respect the right of a resident to refuse to participate.
- Accept: Ensure anonymity / do not ask for names or sensitive personal details.
- Accept: Conduct a pilot study first to test the questions.

**(a)(iii)** [1 mark]:
- Accept: Easier to code / quantify / plot on graphs / compare statistically.
- Reject: "Easier to understand" (this is a benefit of clear phrasing, not closed question structure).

**(b)(i)** [3 marks total]:
- 1 mark for establishing a starting point.
- 1 mark for explaining the selection interval (e.g., "every 5th house" or "every nth door").
- 1 mark for specifying a systematic route / walking pattern (e.g., along a transect line or street).

**(b)(ii)** [2 marks total]:
- 1 mark for Advantage: Gives uniform spatial coverage / avoids clusters / is fast and simple to carry out on-site.
- 1 mark for Disadvantage: Can introduce bias if patterns in the housing layout match the sampling interval / not everyone has an equal chance of being selected.

**(b)(iii)** [1 mark]:
- Accept: More representative of the population / reduces the impact of anomalous or extreme results / increases reliability of the final conclusion.

**(c)(i)** [3 marks total]:
- 1 mark for explaining the scale (either percentage scale up to 100% or absolute scale up to 50 households).
- 1 mark for explaining the division of the two bars into sequential segments according to the values.
- 1 mark for detailing the use of a key / legend with differing colors or shading.

**(c)(ii)** [2 marks total]:
- 1 mark for correct working: \(\frac{15}{50} \times 100\).
- 1 mark for correct calculation: 30%.

**(c)(iii)** [2 marks total]:
- 1 mark for correct working: \(\frac{30}{50} \times 360\) or \(0.6 \times 360\).
- 1 mark for correct calculation: \(216^{\circ}\) (must include degrees or reference to circle share).

**(d)(i)** [4 marks total]:
- 1 mark for explicit hypothesis evaluation (e.g., "The hypothesis is correct / fully supported").
- 1 mark for comparative data point on piped water (e.g., 48 out of 50 in Westlands vs 3 out of 50 in Huruma).
- 1 mark for comparative data point on public standpipes / kiosk (e.g., 25 in Huruma vs only 2 in Westlands).
- 1 mark for comparative data point on tanker trucks (e.g., 15 in Huruma vs 0 in Westlands).
- *Note: To achieve full marks, both raw numbers (or percentages) and explicit comparison of the two areas are required.*

**(d)(ii)** [3 marks total, 1 mark per valid alternative indicator]:
- Accept: Household income levels, unemployment rate, literacy rate / level of education, access to waste collection / garbage disposal, housing construction material, distance to healthcare services.
- Reject: Water supply, cooking fuel (already in the prompt).

**(d)(iii)** [4 marks total]:
- 2 marks (1 mark per difficulty): e.g., Fear of crime / safety risks; Getting lost in poorly-mapped street layouts; Language/dialect barriers; Suspicions of locals towards outsiders.
- 2 marks (1 mark per paired mitigation): e.g., Move in supervised groups during daylight; Hire a trusted local guide / obtain permission from community leaders; Use translators; Show school ID cards to build trust.