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

**Part (a)**
(i) The central commercial, retail, and business core of an urban area, characterized by high land values, high building density, and accessibility.
(ii) Characteristics include: high density of terraced housing or older apartment blocks; derelict land or abandoned factories; higher crime rates; mix of low-order services; ongoing gentrification or redevelopment.
(iii) High-class residential areas are often located on the fringe because: land is cheaper and more plentiful, allowing for larger homes and gardens; lower levels of air and noise pollution; scenic, green environments; improved transport links (highways, commuter rail) that allow easy travel into the center.
(iv) Urban sprawl destroys natural habitats through land clearing, leading to loss of biodiversity; causes deforestation; increases surface runoff and flooding risk due to the expansion of impermeable concrete surfaces; pollutes water sources from construction runoff and residential waste; increases greenhouse gas emissions due to longer vehicle commuter distances.

**Part (b)**
(i) Traffic issues include: long delay times and slow travel speeds during rush hours; increased air pollution and smog from idling vehicles; high levels of noise pollution; economic losses due to late deliveries and wasted working hours; emergency vehicles (e.g., ambulances) being blocked or delayed.
(ii) Strategies include: improving public transport systems (e.g., building underground metro networks, bus rapid transit systems); introducing congestion charging zones (charging drivers to enter the city center); building park-and-ride schemes at the urban periphery; creating dedicated bike lanes and pedestrian-only zones to encourage non-vehicular transport; implementing carpooling lanes and high-occupancy vehicle (HOV) regulations; staggering working/school hours to spread out commuter demand.

**Part (c) Model Case Study: Rocinha, Rio de Janeiro (Brazil)**
In Rocinha, the government and NGOs have used several strategies to improve housing. Under the Favela-Bairro Project, basic services were integrated into the settlement. Dirt tracks were replaced with paved roads to allow access for waste collection vehicles and emergency services, reducing disease and improving safety. Wooden and unstable shelters were replaced with brick and concrete housing structures built with stronger foundations to prevent landslides on steep slopes. Heavy investments were made in sanitation, installing sewage pipes to redirect human waste away from open channels, and providing clean piped water directly to homes. Furthermore, the cable car system (teleférico) was introduced to improve connectivity with the city center, allowing residents easier access to formal jobs, raising their incomes to reinvest in self-help home improvements.

**(a)(i)** 1 mark for a clear definition.
* Accept: The central retail/business hub of a city; the commercial center.
* Reject: Just "the center of town" without commercial/business context.

**(a)(ii)** 1 mark per valid characteristic up to 2 marks.
* Accept: High-density terraced housing; older, low-quality housing; industrial/derelict land; multi-ethnic communities; redevelopment/gentrification; high crime rates.

**(a)(iii)** 1 mark per valid explanation up to 3 marks.
* Accept: Cheaper land allows larger houses/gardens; quieter/less air pollution; green spaces/closer to nature; good transport links/highways allow easy commuting.

**(a)(iv)** 1 mark per valid explanation up to 4 marks.
* Accept: Deforestation/loss of vegetation; habitat fragmentation/loss of biodiversity; soil erosion; increased surface runoff/flooding due to impermeable surfaces; air/water pollution from construction/traffic.

**(b)(i)** 1 mark per valid descriptive point up to 3 marks.
* Accept: Gridlock/long queues/delays; smog/air pollution; noise pollution; delayed emergency services; road rage/stress; economic losses from delays.

**(b)(ii)** 1 mark per valid point (up to 5 marks) with development allowed.
* Accept: Bus rapid transit / metro schemes (1 mark); congestion pricing (1 mark); park and ride (1 mark); bike lanes/pedestrianization (1 mark); carpooling lanes (1 mark); staggering work hours (1 mark).

**(c)** Case Study Marking Scheme (7 marks):
* **Level 1 (1-3 marks):** Simple, general statements describing housing improvements (e.g., they put in running water, rebuilt houses, added roads) with no or limited specific detail of a named urban area.
* **Level 2 (4-6 marks):** Developed statements showing geographical understanding of specific strategies used in a named slum/informal settlement (e.g., describing the Favela-Bairro scheme in Rio de Janeiro, highlighting concrete brick replacement on slopes and sewage pipe installation).
* **Level 3 (7 marks):** Fully developed, comprehensive case study of a named, specific urban area. Precise details, specific locations, and clear, integrated descriptions and explanations of the success or implementation of multiple housing improvement strategies.

**Part (a)**
(i) Discharge.
(ii) Traction involves large, heavy rocks and boulders rolling or sliding along the river bed (1 mark), whereas saltation involves smaller pebbles and coarse sand bouncing or hopping along the river bed (1 mark).
(iii) A waterfall forms where a river flows over a layer of hard, resistant rock overlying softer, less resistant rock. The soft rock is eroded more rapidly by hydraulic action and abrasion, creating a step. Over time, the soft rock is undercut, leaving an overhanging ledge of hard rock. This ledge eventually collapses under its own weight into the plunge pool below, causing the waterfall to retreat upstream and leave a steep-sided gorge.
(iv) On the outer bend of a meander, water flows fastest, creating high energy. This leads to lateral erosion (via hydraulic action and abrasion) which undercuts the bank, forming a river cliff. On the inner bend, the velocity is slowest, reducing energy and causing the river to deposit its load, forming a slip-off slope. Over time, this dual process of erosion on the outside and deposition on the inside causes the meander bend to migrate and become more pronounced.

**Part (b)**
(i) Deforestation removes vegetation that would intercept rainfall and absorb water, increasing surface runoff; urbanization covers the land with impermeable surfaces (concrete, tarmac), reducing infiltration and speeding up runoff into storm drains; building near rivers reduces the natural floodplain capacity.
(ii) Soft engineering works with natural processes to reduce flood risk. Strategies include: afforestation (planting trees in the upper catchment to increase interception and delay lag time); wetland restoration (allowing wetlands to act as natural sponges that store excess water); river restoration (returning modified, straight channels to their natural meandering state to slow down water flow); flood plain zoning (restricting building on floodplains, allowing them to flood naturally without damaging high-value property).

**Part (c) Model Case Study: River Ganges / Brahmaputra (Bangladesh)**
Bangladesh suffered devastating floods due to both physical and human factors. Physically, the region experienced exceptionally heavy monsoon rains over a short period, combined with rapid snowmelt from the Himalayas in spring. This caused huge volumes of water to enter the river systems simultaneously. Human factors included extensive deforestation in the upper catchment areas of Nepal and India, which significantly reduced interception rates and increased surface runoff and soil erosion, silting up the river beds. The impacts on people were catastrophic. Over 60% of the land area was submerged, destroying agricultural fields and rice crops, leading to severe food shortages. Millions of homes were damaged, leaving millions homeless. Water supplies were contaminated with sewage, causing outbreaks of waterborne diseases such as cholera and typhoid. Crucial transport infrastructure, including roads and bridges, was washed away, preventing aid from reaching isolated rural communities.

**(a)(i)** 1 mark for "Discharge".

**(a)(ii)** 1 mark for describing traction (rolling/sliding of large stones); 1 mark for describing saltation (bouncing/hopping of smaller stones).

**(a)(iii)** 1 mark per valid point up to 3 marks.
* Accept: Hard rock over soft rock (1 mark); differential erosion/undercutting of soft rock (1 mark); collapse of overhanging hard rock (1 mark); retreat of waterfall/gorge formation (1 mark).

**(a)(iv)** 1 mark per valid point up to 4 marks.
* Accept: Fast water on the outer bend causes lateral erosion (1 mark); forms a river cliff (1 mark); slow water on the inner bend causes deposition (1 mark); forms a slip-off slope (1 mark).

**(b)(i)** 1 mark per valid human activity explained up to 3 marks.
* Accept: Deforestation reduces interception/increases runoff; urbanization/impermeable surfaces prevent infiltration; channelization can increase water velocity downstream.

**(b)(ii)** 1 mark per valid soft engineering strategy explained (up to 5 marks with development).
* Accept: Afforestation (1 mark) + explanation of interception (1 mark); flood plain zoning (1 mark) + explanation of keeping buildings away from risk areas (1 mark); river restoration (1 mark); wetland creation (1 mark).

**(c)** Case Study Marking Scheme (7 marks):
* **Level 1 (1-3 marks):** Simple, general statements explaining why rivers flood and general impacts (e.g., it rained a lot, houses were destroyed, people drowned).
* **Level 2 (4-6 marks):** Developed statements showing understanding of the specific causes (e.g., monsoon rains, snowmelt, Himalayan deforestation) and specific impacts (e.g., cholera outbreak, destruction of rice crops, loss of road infrastructure) on a named river basin.
* **Level 3 (7 marks):** Fully developed case study of a named, specific river basin. Clear integration of both physical/human causes and detailed, localized impacts on the population with named places/data.

**Part (a)**
(i) Farming where crops are grown and livestock are reared primarily to feed the farmer and their family, with little or no surplus left over for sale.
(ii) Solar energy (sunlight), precipitation (rainfall), soil type, slope of the land (relief), or temperature.
(iii) Intensive farming involves a high level of inputs (such as labor, capital, fertilizers) relative to a small area of land to maximize yield per hectare (1 mark), whereas extensive farming involves a low level of inputs relative to a very large area of land, resulting in low yield per hectare but high overall production (1 mark). Intensive has high yields per unit area, extensive has low yields per unit area (1 mark).
(iv) Commercial farmers use chemical fertilizers to add vital nutrients to the soil, promoting faster growth; high-yielding variety (HYV) or genetically modified (GM) seeds that resist disease and drought; modern machinery (e.g., tractors, combine harvesters) to increase efficiency and speed up planting/harvesting; automated drip irrigation systems to provide optimal water levels to crops.

**Part (b)**
(i) Physical causes include: prolonged droughts that dry out soil and kill crops; severe flooding that washes away crops and topsoil; pests and diseases (e.g., locust swarms) that consume and destroy entire harvests; extreme temperatures (frosts or heatwaves) that prevent seed germination.
(ii) Human consequences include: widespread malnutrition and starvation, especially in children; increased susceptibility to diseases due to weakened immune systems; spikes in infant mortality rates; migration of people (food refugees) away from rural areas to urban centers or neighboring nations; social unrest, food riots, and political instability over scarce resources; inflation of food prices, making basic sustenance unaffordable.

**Part (c) Model Case Study: Intensive Wet Rice Cultivation in the Ganges Valley (India/Bangladesh)**
In the Ganges Valley, the farming system is intensive wet rice cultivation.
**Inputs** include physical elements such as high average temperatures (above 21°C), flat fertile alluvial soils deposited by the Ganges River floods, and heavy summer monsoon rainfall (over 2000 mm). Human inputs include a large and cheap labor force, simple hand tools (plows, sickles), water buffaloes for draft labor, and increasingly high-yielding variety (HYV) seeds like IR8.
**Processes** include preparing the soil using wooden plows drawn by water buffaloes, building earthen bunds (low walls) around fields to trap water, flooding the fields, transplanting rice seedlings by hand from nurseries into the flooded padi fields, weeding by hand, harvesting the crop using sickles, and threshing the rice manually against wooden boards.
**Outputs** include the primary crop of rice grain (mostly consumed by the family), rice straw (used as animal feed or thatch), and manure from the water buffaloes which is recycled back into the soil as a fertilizer input.

**(a)(i)** 1 mark for a clear definition.
* Accept: Farming to feed yourself/family; farming with no commercial surplus.

**(a)(ii)** 1 mark per valid physical input up to 2 marks.
* Accept: Soil; rainfall; temperature; solar energy; slope/relief.
* Reject: Fertilizers, tractors, seeds (human/capital inputs).

**(a)(iii)** 1 mark for intensive definition, 1 mark for extensive definition, 1 mark for comparative analysis.
* Accept: Intensive uses small land but high inputs/capital; extensive uses large land with low inputs; intensive has high yields per hectare, extensive has low yields per hectare.

**(a)(iv)** 1 mark per valid point explained up to 4 marks.
* Accept: High-yielding variety (HYV) seeds (1 mark); chemical fertilizers/pesticides (1 mark); mechanized harvesting/tractors (1 mark); irrigation systems (1 mark); genetic modification (1 mark).

**(b)(i)** 1 mark per valid physical cause up to 3 marks.
* Accept: Drought; floods; pests/diseases; extreme temperatures; soil erosion due to wind/storms.

**(b)(ii)** 1 mark per valid human consequence (up to 5 marks with development).
* Accept: Famine/malnutrition (1 mark); increased death rates (1 mark); disease outbreaks (1 mark); rural-to-urban migration (1 mark); food riots/civil unrest (1 mark); loss of income/poverty (1 mark).

**(c)** Case Study Marking Scheme (7 marks):
* **Level 1 (1-3 marks):** Simple, general statements listing basic agricultural inputs, processes, and outputs without detailed context (e.g., they use soil and water, they plant seeds and harvest them, they get crops).
* **Level 2 (4-6 marks):** Developed statements showing clear classification into inputs, processes, and outputs for a named farm or agricultural system (e.g., wet rice cultivation in India: alluvial soil as input, hand transplanting in flooded paddies as a process, rice grain as output).
* **Level 3 (7 marks):** Fully developed case study of a named farm or specific agricultural system. Complete, well-structured, and balanced description of physical and human inputs, precise manual/mechanized processes, and primary/secondary outputs with specific local/technical details.

(a) (i) Church with a tower / Place of worship with tower. (ii) 461807 or 462807. (iii) \(3700\text{ m}\) (acceptable range: \(3600\text{ m}\) to \(3800\text{ m}\)). (iv) East-North-East (ENE) or East (allow bearings between \(70^\circ\) and \(85^\circ\)). (b) The river meanders/winds through the valley floor. It flows generally from the north-west to the south-east. The valley floor is wide and flat (floodplain), while the valley sides rise steeply to the north and south. There is marsh/wetland on the floodplain, and a tributary stream joins the main river from the north. (c) (i) The settlements are dispersed or scattered. There is a linear pattern along the secondary road. Settlement density is very low, consisting mainly of isolated farmsteads (e.g., Highfield Farm). Settlements are located on the flatter, higher ground to avoid steep slopes. (ii) Function 1: Transport Hub - Evidence: presence of a railway station and junction of multiple primary roads. Function 2: Tourism/Recreation - Evidence: presence of a museum/tourist information centre. (d) (i) The slope is initially steep near the start (\(185\text{ m}\) down to \(150\text{ m}\)), then it becomes very gentle/flat on a terrace or spur (between \(150\text{ m}\) and \(130\text{ m}\)), before becoming steep again as it descends to the floodplain (\(130\text{ m}\) down to \(100\text{ m}\)), and finally flat on the valley floor. (ii) No, because there is intervening high ground / a ridge rising above \(210\text{ m}\) in grid square 4581 which blocks the line of sight.

Part (a) [6 marks]: (i) Award 1 mark for correct identification: Church with tower / Place of worship. (ii) Award 2 marks for exact 6-figure grid reference: 461807 or 462807 (1 mark for correct square 4680, 2 marks for exact reference within tolerance). (iii) Award 2 marks for correct distance: \(3700\text{ m}\) (allow \(3600\text{ m}\) to \(3800\text{ m}\)). Award 1 mark if distance is given in km (\(3.6\text{ km}\) to \(3.8\text{ km}\)) or if slightly out of range but correct method shown. (iv) Award 1 mark for: East-North-East (ENE) or East / bearing of \(70^\circ\) to \(85^\circ\). Part (b) [5 marks]: Award 1 mark for each valid descriptive point of physical features (up to 5 marks): - Meandering/winding river course. - Wide/flat valley floor/floodplain. - Steep valley sides/slopes. - Flows north-west to south-east. - Presence of marsh/wetland. - Tributary stream joining main river. Part (c) [5 marks]: (i) Award 1 mark for each valid point describing settlement pattern (up to 3 marks): - Dispersed/scattered. - Linear along roads. - Low density/isolated farms. - Located on flatter high ground / avoiding steep slopes. (ii) Award 1 mark for each correct function with corresponding evidence (up to 2 marks): - Transport (junction of roads / railway station). - Tourism/Recreation (museum / tourist information centre). Part (d) [4 marks]: (i) Award 1 mark for each gradient stage correctly identified (up to 3 marks): - Starts steep. - Becomes gentle/flat (terrace/spur). - Steeps up again. - Flattens out at the bottom. (ii) Award 1 mark for correct answer with reason: - No, because of intervening high ground / a ridge (over \(210\text{ m}\)) in square 4581 blocking the line of sight.

(a) Since the map scale is 1:25,000, 1 cm on the map represents 25,000 cm (0.25 km) on the ground.
Ground distance = \(12 \text{ cm} \times 0.25 \text{ km/cm} = 3.0 \text{ km}\).

(b) Height difference (Rise) = \(270\text{m} - 120\text{m} = 150\text{m}\).
Horizontal distance (Run) = \(3.0 \text{ km} = 3000\text{m}\).
Gradient = \(\frac{\text{Rise}}{\text{Run}} = \frac{150\text{m}}{3000\text{m}} = \frac{1}{20}\) (or 0.05).

(c) In a 1:25,000 map, each grid square is 1 km wide. Moving 2 km East of Point A (124 456) means adding 2 to the Eastings: \(12 + 2 = 14\). The Northing remains unchanged. Therefore, the grid reference is 144 456.

(d) A blue line represents a river, and the arrowhead shows the flow direction (South-West).

(a) 1 mark for correct method (e.g., multiplying 12 by 0.25 or equivalent conversion scale).
1 mark for correct accuracy (3.0 km).

(b) 1 mark for correct calculation of vertical interval (150 m) and horizontal distance (3000 m).
1 mark for correct final gradient calculation (1 in 20, 1:20, or 0.05).

(c) 1 mark for correct Easting (144).
1 mark for correct Northing (456).

(d) 1 mark for identifying the river.
1 mark for identifying the correct direction of flow (South-West).

(a) Depositional landforms include beaches, sand dunes, spits, bars, and tombolos.

(b) Constructive waves are low-frequency waves (6-8 per minute) with a strong swash that deposits sediment and a weak backwash. Destructive waves are high-frequency waves (10-14 per minute) with a weak swash and a powerful backwash that erodes the beach.

(c) Hard engineering methods include sea walls (reflect wave energy), groynes (trap sediment from longshore drift), and gabions/rip-rap (absorb wave energy).

(a) 1 mark for each valid depositional landform (Accept: beach, sand dune, bar, tombolo, salt marsh). Max 2 marks.

(b) 1 mark for comparing frequency (constructive low/destructive high).
1 mark for describing constructive wave action (strong swash / weak backwash).
1 mark for describing destructive wave action (weak swash / strong backwash).

(c) 1 mark for each valid hard engineering technique (Accept: sea walls, groynes, rip-rap/rock armour, gabions, revetments, offshore breakwaters). Max 3 marks.

(a) Annual range = Maximum Temp - Minimum Temp = \(31^\circ\text{C} - (-5^\circ\text{C}) = 36^\circ\text{C}\).

(b) A wind vane measures wind direction. It must be positioned high up (e.g., on a roof) or in an open area to avoid trees or buildings blocking or deflecting the wind.

(c) A Stevenson Screen is painted white to reflect solar radiation and keep the interior cool. It has double-louvred (slatted) sides to allow air to pass through freely while preventing direct sunlight from hitting the instruments.

(d) Weather refers to short-term, day-to-day atmospheric conditions (e.g., temperature, rain today). Climate is the long-term average of these weather conditions, usually calculated over 30 years.

(a) 1 mark for showing correct working (31 - (-5)).
1 mark for correct final temperature range value (36°C).

(b) 1 mark for identifying the wind vane.
1 mark for describing an appropriate location (open space, elevated position/roof, away from obstructions).

(c) 1 mark for each valid design feature identified and linked to protection from solar radiation (e.g., painted white to reflect solar rays; louvred/slatted sides to block direct sunlight but allow air flow; double roof to insulate). Max 2 marks.

(d) 1 mark for defining weather (short-term/day-to-day conditions).
1 mark for defining climate (long-term average/30-year trend).

(a) Natural population growth rate = \(\text{Birth rate} - \text{Death rate} = 28 - 8 = 20 \text{ per } 1,000\).
Converted to a percentage: \(\frac{20}{1000} \times 100 = 2.0\%\).

(b) Economically active population (15-64) = \(80 - (24 + 8) = 48\) million.
Dependency Ratio = \(\frac{\text{Young dependents (24)} + \text{Elderly dependents (8)}}{\text{Economically active (48)}} \times 100 = \frac{32}{48} \times 100 = 66.67\%\).

(c) A country with a high natural growth rate has a high birth rate, leading to a wide base on the pyramid. A high death rate or lower life expectancy results in rapidly concave, narrowing sides toward the apex.

(d) Decreases in death rates are driven by factors such as improved medical care (vaccinations), better sanitation, clean water access, and improved agricultural production/nutrition security.

(a) 1 mark for calculating natural increase per 1,000 (20 per 1,000).
1 mark for correct percentage (2.0%).

(b) 1 mark for calculating the economically active cohort (48 million).
1 mark for correct final dependency ratio (66.67% or 67%).

(c) 1 mark for each valid shape feature described (e.g., broad/wide base; steeply sloping sides; narrow apex). Max 2 marks.

(d) 1 mark for each valid factor (e.g., improved healthcare/hospitals, vaccinations, clean water supply, better sanitation, improved diet/food supply). Max 2 marks.

(a) The Central Business District (CBD) contains the peak land value intersection, leading to vertical high-rise development to maximize land usage.

(b) The Burgess Model posits that cities expand outwards in rings from the CBD (Zone 1). Zone 2 is the zone of transition (factories/low-quality housing), Zone 3 is working-class homes, Zone 4 is modern middle-class suburbs, and Zone 5 is the outer commuter ring.

(c) Pull factors include higher-paying employment opportunities, access to schools/universities, modern medical facilities, reliable infrastructure, and social/recreational amenities.

(d) Gentrification refers to the socio-cultural and economic rehabilitation of run-down urban neighborhoods by middle-to-high-income earners, often displacing the original lower-income residents.

(a) 1 mark for Central Business District (or CBD).

(b) 1 mark for stating that land use changes in concentric rings radiating from the center.
1 mark for naming at least two zones in correct order (e.g., CBD in center, followed by transition zone / working-class housing).
1 mark for explaining that accessibility/rent decreases as distance from the CBD increases.

(c) 1 mark for each valid pull factor (Accept: employment opportunities, higher wages, better schools/universities, superior healthcare/hospitals, better electricity/water infrastructure, entertainment). Max 3 marks.

(d) 1 mark for a clear definition of gentrification (updating/redevelopment of lower-class areas leading to influx of wealthier residents).

Detailed Step-by-Step Solution:

- **Part (a)(i)**: Systematic sampling involves choosing sites at regular intervals. The students use a map to draw a 5 km transect starting at the CBD (0 km). They mark points every 1 km (0 km, 1 km, 2 km, 3 km, 4 km, 5 km) to create 6 sampling locations.
- **Part (a)(ii)**: Safety measures are crucial in urban fieldwork. Appropriate precautions include wearing high-visibility vests to be visible to motorists, staying on the pavement/sidewalk, and crossing busy roads only at designated pedestrian crossings.
- **Part (a)(iii)**: Systematic sampling ensures uniform coverage and removes subjective selection bias. However, a disadvantage is that it can miss local variations (e.g., a nice park located at 2.5 km would be missed) or some intervals might land on dangerous/inaccessible roads.
- **Part (b)(i)**: Standard physical and aesthetic environmental quality indicators in urban geography include: level of litter/cleanliness, traffic noise/volume, air quality (smoke/exhaust), quality of building maintenance, and percentage of green space/vegetation.
- **Part (b)(ii)**: A bipolar scale assesses a range from extremely negative to extremely positive. Students define a standard rubric (e.g., for noise: -2 = deafening road/industrial noise, 0 = average background urban hum, +2 = peaceful/natural sounds only) and assign a score based on consensual group assessment.
- **Part (b)(iii)**: Add the scores together: \( (+1) + 0 + (+1) + (-1) + (+1) = +2 \).
- **Part (b)(iv)**: Human perceptions differ (subjective bias). This is mitigated by establishing clear scoring rubrics, training students beforehand, and using the average score of multiple independent student assessments.
- **Part (c)(i)**: To construct a bar graph, plot the independent variable (Sites 1-6) on the x-axis and the dependent variable (EQI Score) on the y-axis (with negative values below the origin). Draw bars to the calculated heights.
- **Part (c)(ii)**: Assess Hypothesis 1 using data. The hypothesis states quality decreases towards industrial zones and increases towards suburbs. Data: Site 1 is +6. It decreases to -3 (Site 2) and -1 (Site 3) near industrial/inner-city zones. It then rises to +2 (Site 4), +5 (Site 5), and +8 (Site 6). The hypothesis is supported as quality dips in the middle sites and is highest at the fringe (+8), but the high CBD score (+6) shows that the decrease only starts *after* leaving the CBD.
- **Part (c)(iii)**: A divided bar chart uses a 100% scale. Create a single bar for each site, dividing the bar proportionally (e.g., if Site 4 is 60% residential, that segment occupies 60% of the bar's length). Use distinct colors/patterns and a key.
- **Part (c)(iv)**: Bid-rent theory explains that land prices decrease with distance from the CBD. Retailers and offices require high footfall and can afford the highest rents in the CBD. Residential users need more space and cannot afford CBD rents, so they settle in suburban zones where land is cheaper.
- **Part (d)(i)**: Reliability is improved by reducing temporal anomalies and increasing data volume. Students should repeat the data collection on different days of the week and at different times (morning, afternoon) to account for variations in traffic/litter, and use digital sensors (for noise/air quality) to replace subjective observation with objective data.

Total Marks: 30

Part (a) [6 marks]
- (i) [2 marks] Award 1 mark for mentioning measuring/using a fixed/regular interval (e.g., every 1 km); Award 1 mark for referencing the transect starting from the CBD (0 km to 5 km).
- (ii) [2 marks] Award 1 mark each for any two sensible safety precautions (e.g., wear high-vis clothing, stay on pavements, use pedestrian crossings, work in groups, carry a first-aid kit/mobile phone). Do not accept vague answers like 'be careful'.
- (iii) [2 marks] Award 1 mark for a valid advantage (e.g., straightforward to carry out, eliminates researcher bias, even coverage); Award 1 mark for a valid disadvantage (e.g., may miss features between sample points, a site may be inaccessible or hazardous).

Part (b) [10 marks]
- (i) [3 marks] Award 1 mark each for up to three valid urban environmental categories (e.g., litter/cleanliness, noise levels, air pollution/smoke, traffic congestion, building condition/maintenance, lack of green space/vegetation).
- (ii) [3 marks] Award 1 mark for explaining what the end-member scores represent (e.g., -2 is very poor/highly polluted, +2 is pristine/excellent); Award 1 mark for explaining how a neutral score of 0 is used; Award 1 mark for explaining the process of assessment (e.g., students observe for a fixed period like 5 minutes and agree on a score based on a predetermined rubric/description sheet).
- (iii) [2 marks] Award 2 marks for the correct calculation: +2. (Award 1 mark if math process is correct but arithmetic error occurs, e.g., showing the sum of the numbers but getting a different value).
- (iv) [2 marks] Award 1 mark for identifying the source of bias (e.g., personal opinion, differing standards of what is clean/noisy); Award 1 mark for a valid solution (e.g., averaging scores of multiple students, using instrument/digital meters, using a photographic reference guide).

Part (c) [10 marks]
- (i) [2 marks] Award 1 mark for describing axes (x-axis: Sites/Distance, y-axis: EQI scores with negative scale below zero); Award 1 mark for drawing bars above/below the horizontal axis representing the values.
- (ii) [4 marks] Award 1 mark for stating that the hypothesis is partially supported/true. Award up to 2 marks for trend description using data (e.g., EQI decreases from CBD (+6) to Site 2 (-3), then increases steadily to Site 6 (+8) at the rural-urban fringe). Award 1 mark for pointing out the anomaly/nuance (e.g., CBD at Site 1 starts high (+6), so the decrease only begins after leaving the CBD).
- (iii) [2 marks] Award 1 mark for describing the bar scale (e.g., bars of equal total length representing 100% at each site); Award 1 mark for describing proportional segmenting and inclusion of a key/color code.
- (iv) [2 marks] Award 1 mark for referring to bid-rent theory / land values decreasing with distance from the CBD; Award 1 mark for explaining that commercial activities can afford high rents/need high accessibility, whereas residential land use requires more space and locates where land is cheaper.

Part (d) [4 marks]
- (i) [4 marks] Award 1 mark each for up to four distinct improvements to reliability (e.g., repeat study on multiple days (weekdays vs. weekends); repeat at different times of day (rush hour vs. midday); use digital/scientific equipment (e.g., decibel meter, particulate matter sensor) to remove subjectivity; increase the number of sample sites (e.g., every 500m); have more groups collect data and calculate a mean).

(a)(i) Two safety precautions: Wear sturdy waterproof footwear with good grip to avoid slipping; do not enter the river if the water level is too deep or the flow is too fast; check weather forecasts beforehand to avoid sudden flash flooding; work in pairs or groups; carry a first aid kit. (a)(ii) To measure wet width: Stretch a tape measure tightly across the river from one bank where the water meets the land to the opposite bank. Ensure the tape is kept horizontal and close to the water surface without dipping into it. Read the measurement perpendicular to the flow. (b) To measure depth systematically: Divide the measured channel width into equal intervals (e.g., every 0.5 meters). At each interval, lower a vertical measuring rule (or graduated metrestick) into the water until it touches the river bed. Read the depth at the water surface, ensuring the flat side of the ruler faces the flow to minimize water piling. Record depth at each point and average them. (c)(i) To measure velocity using a float: Measure a fixed distance (e.g., 10 meters) along a straight section of the river bank using a tape measure and mark the start and end points. Release a buoyant float (like an orange peel) slightly upstream of the start point. Start the stopwatch as the float passes the start marker. Stop the stopwatch as it passes the end marker. Repeat this test 3 to 5 times across different points of the channel width to calculate an average travel time, then divide distance by average time to find velocity. (c)(ii) Disadvantage of float: Floats only measure surface velocity which is affected by wind and friction, or they can get caught in vegetation/eddies. Alternative: Use a digital flowmeter (impeller flow meter) which measures velocity at different depths. (d)(i) Representative pebble sampling: Use a systematic approach (e.g., taking a pebble at regular intervals across the river bed, such as every 10cm or at intersections of a grid) or random sampling (using a random number generator to select coordinates on a grid). Avoid looking at the river bed when picking up the pebble to prevent bias toward larger or more colorful stones. (d)(ii) Measuring pebble size: Use a sliding caliper or ruler to measure the longest axis of the pebble in centimeters or millimeters. (d)(iii) Using a roundness chart: Compare each pebble visually against a standardized visual scale showing drawings of pebbles categorized from very angular to well-rounded. Assign a numerical value or category based on the closest visual match. (e)(i) Agreement with Hypothesis 1: Fully agree. The cross-sectional area increases downstream from Site 1 to Site 3. Site 1 area is 0.168 m2, Site 2 area is 0.896 m2, and Site 3 area is 2.610 m2. (e)(ii) Evaluation of Hypothesis 2: The hypothesis is supported. Mean pebble size decreases downstream from 14.2cm at Site 1, to 8.5cm at Site 2, and 3.1cm at Site 3. At the same time, the percentage of rounded/well-rounded pebbles increases downstream from 10 percent at Site 1, to 45 percent at Site 2, and 80 percent at Site 3. (e)(iii) Physical processes: Attrition causes pebbles to collide with each other and the bed/banks, chipping away sharp edges to make them rounder and smaller. Corrasion/abrasion involves the river's load wearing away the bed and banks, also wearing down the sediment itself.

Total: 30 Marks. (a)(i) [2 marks] 1 mark per valid precaution. Accept: non-slip footwear, checking weather forecast, working in groups, avoiding deep/fast-flowing water. Reject: general safety like 'wear a coat'. (a)(ii) [3 marks] 1 mark for securing tape on both banks at water level; 1 mark for ensuring tape is taut/horizontal; 1 mark for reading at water edge. (b) [4 marks] 1 mark for calculating equal intervals based on total width; 1 mark for placing metrestick/ruler vertically to touch the bed; 1 mark for reading at water level; 1 mark for facing the narrow edge of the ruler upstream to reduce resistance/water piling. (c)(i) [4 marks] 1 mark for measuring a set distance along a straight stretch; 1 mark for releasing float upstream of start line; 1 mark for timing with stopwatch from start to end; 1 mark for repeating multiple times and calculating mean. (c)(ii) [2 marks] 1 mark for disadvantage (e.g. surface-only measurement, wind interference, snagging on debris); 1 mark for alternative (flowmeter/impeller). (d)(i) [3 marks] 1 mark for systematic selection (e.g. touch toe down at every step and pick up the pebble it touches); 1 mark for avoiding bias (e.g. not looking down, picking first pebble touched); 1 mark for sampling across the whole width. (d)(ii) [2 marks] 1 mark for using calipers/ruler; 1 mark for measuring the absolute longest axis of the pebble. (d)(iii) [2 marks] 1 mark for comparing shape to standard reference silhouettes; 1 mark for categorizing/scoring based on scale (from angular to well-rounded). (e)(i) [3 marks] 1 mark for agreeing/stating hypothesis is correct; 2 marks for supporting with data from all three sites (0.168 m2 at Site 1, 0.896 m2 at Site 2, and 2.610 m2 at Site 3). Both units and comparative data must be correct for full marks. (e)(ii) [3 marks] 1 mark for confirming hypothesis is supported; 1 mark for pebble size data (14.2cm to 8.5cm to 3.1cm); 1 mark for roundness percentage data (10 percent to 45 percent to 80 percent). (e)(iii) [2 marks] 1 mark for attrition (rocks colliding and breaking/smoothing); 1 mark for abrasion/corrasion (scraping against riverbed smoothing them).