WAEC SSCE - Geography - 1991 (Essay)

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Important features of Koppen's climatic classification

Wladimir Koppen produced an empirical (quantitative) classification of world climates whose main features are:

• Based on temperature and rainfall: it uses actual measured monthly and annual values of temperature and precipitation as the criteria, rather than causes of climate.
• Based on vegetation: the boundaries between climatic types are chosen to correspond with the limits of natural vegetation belts, on the assumption that vegetation reflects climate.
• Uses a system of letters: each climate is given a code of letters. The first (capital) letter gives the five major groups: A (tropical rainy), B (dry), C (warm temperate/mesothermal), D (cold temperate/microthermal) and E (polar). A special H is sometimes added for highland climates.
• Second and third letters give sub-types: the second letter describes the seasonal rainfall (e.g. f = rain all year, w = dry winter, s = dry summer, m = monsoon), and a third letter gives finer temperature detail. This gives combinations such as Af (equatorial), Aw (tropical wet-and-dry/savanna), BW (desert), BS (steppe), Cf, Cs (Mediterranean), etc.
• Defined by fixed temperature/rainfall limits: each group has precise threshold values (for example the 18°C isotherm for the coldest month separates A from C, and dryness is defined by a temperature-rainfall formula), making the scheme objective and easy to map.

Its strengths are that it is quantitative, worldwide and easy to apply; its weakness is that it stresses average values and vegetation rather than the atmospheric causes of climate.

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(a) Meaning of hinterland

A hinterland is the inland area served by, and trading through, a sea port. It is the region from which the port draws its exports (raw materials, produce) and to which it distributes its imports. For example, most of northern and central Nigeria forms part of the hinterland of the port of Lagos (Apapa).

(b) Importance of sea ports in the economy of Nigeria (with examples)

• Handling of foreign trade: ports such as Lagos (Apapa/Tin Can Island), Port Harcourt, Warri, Calabar and Onne handle the bulk of Nigeria's imports and exports (petroleum, cocoa, manufactured goods).
• Export of oil and revenue: the oil terminals (e.g. Bonny, Escravos) export crude oil, earning the greater part of national foreign exchange and revenue.
• Employment and urban growth: ports create jobs (dockworkers, shipping, clearing) and have stimulated the growth of large port cities.
• Industrial growth: port locations attract industries (refineries, cement, manufacturing) that use imported materials, and they link Nigeria to landlocked neighbours.

(c) Four problems of port development in Nigeria

• Silting and shallow water at some harbours, requiring costly dredging to admit large ships.
• Congestion of ships, cargo and traffic, causing long delays.
• Inadequate/obsolete equipment and infrastructure and poor access roads and railways to the hinterland.
• High cost of construction and maintenance, bureaucracy/corruption, and over-concentration of traffic on Lagos ports.

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(a) Characteristics and (b) formation of each rock type

(i) Granite

• Characteristics: a hard, crystalline igneous rock, coarse-grained with large interlocking crystals of quartz, feldspar and mica; light in colour, resistant to weathering, non-porous and non-bedded (no layers or fossils).
• Formation: formed by the slow cooling and solidification of molten magma deep below the earth's surface (a plutonic/intrusive igneous rock). Slow cooling allows the large crystals to grow.

(ii) Limestone

• Characteristics: a sedimentary rock made largely of calcium carbonate; usually well-bedded (layered), often contains fossils, is porous and jointed, and reacts with (is dissolved by) dilute acid and rain water.
• Formation: formed by the accumulation and compaction of the shells and skeletons of marine organisms (or by chemical precipitation of calcium carbonate) on the sea floor, later cemented and hardened into rock.

(iii) Graphite

• Characteristics: a soft, dark-grey to black, greasy/smooth metamorphic rock (form of carbon); it is a good conductor of heat and electricity and marks paper (used in pencils).
• Formation: formed by the metamorphism (alteration by great heat and pressure) of carbon-rich rocks such as coal or organic sediments deep within the earth's crust.

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(a) Outline map of West Africa: ECOWAS members and capitals

On the outline, locate and name (examples):

• (i) Two coastal ECOWAS members: Nigeria (capital Abuja) and Ghana (capital Accra). Other coastal members: Senegal (Dakar), Cote d'Ivoire (Yamoussoukro), Liberia (Monrovia), Togo (Lome), Benin (Porto-Novo).
• (ii) Two interior (landlocked) ECOWAS members: Niger (capital Niamey) and Mali (capital Bamako). The other landlocked member is Burkina Faso (Ouagadougou).
• (iii) Mark each capital with a dot beside the country name as above.

(b) Six benefits a member derives from ECOWAS (e.g. Nigeria)

• Free movement of persons: citizens can travel, live and work within member states without visas.
• Free trade / larger market: removal of tariffs and trade barriers widens the market for its goods and promotes intra-regional trade.
• Economic cooperation and joint projects: shared development of roads, power, communications and a common currency proposal.
• Collective security and peace-keeping: the ECOMOG/standby force helps keep peace and stability in the region.
• Bigger bargaining power: the group negotiates as a bloc with the outside world, obtaining better trade and aid terms.
• Employment and investment opportunities: a wider market and free movement attract investment, create jobs and promote cultural and technical exchange among members.

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(a) Factors favouring rapid growth of population

Two physical factors:

• Favourable climate: a moderate, healthy climate (neither too hot, cold nor too wet) encourages settlement and reduces death from harsh conditions.
• Fertile soils and adequate water: productive land and reliable water supply provide abundant food, supporting a large and growing population (e.g. river valleys and lowlands).

Two human factors:

• Improved medical services: better health care, immunisation and control of disease lower the death rate, especially infant mortality, so population grows.
• High birth rate and immigration: early marriage, large-family customs and religious/social attitudes keep the birth rate high, while good economic opportunities (jobs, industry) attract in-migrants.

(b) Five problems arising from rapid population growth

• Pressure on food supply, leading to food shortage, high prices and possible famine.
• Unemployment and underemployment, as jobs cannot grow as fast as the labour force.
• Shortage of housing, giving rise to overcrowding and slums.
• Strain on social services and infrastructure (schools, hospitals, water, electricity, roads, transport), which become inadequate.
• Environmental problems and pressure on land, including deforestation, over-farming, pollution, waste disposal problems and rural-urban migration/congestion.

Also acceptable: increased crime rate and social vices; low per-capita income and poverty.

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(a) Three types of rural settlement and their characteristics

• Nucleated (clustered) settlement: houses are grouped closely together in a compact village, often around a central feature such as a market, well, church or road junction; farmland lies around the built-up cluster. It develops where water is localised or for defence and social convenience.
• Dispersed (scattered) settlement: individual houses/farmsteads are spread widely apart, each standing on its own farmland, with no central cluster. It is common where water is widely available and land is farmed individually.
• Linear (ribbon) settlement: houses are strung out in a line along a road, river bank, coast or valley, one or two buildings deep, following the line of the routeway or water body.

(Other acceptable type: compact/roadside or planned settlement.)

(b) Four ways rural and urban settlements are interdependent

• Food supply: rural areas produce food and raw materials for the urban population and for urban industries.
• Market and manufactured goods: urban centres provide a market for rural produce and supply the countryside with manufactured goods and equipment.
• Labour and services: rural areas supply labour and migrants to the towns, while towns provide higher-order services (hospitals, higher schools, banks, administration) used by rural dwellers.
• Employment and remittances: town-dwellers send money (remittances) back to rural relatives, and both are linked by transport, trade and communication networks.

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Five factors that determine the volume of trade between Nigeria and Ghana

• Range and differences in products: trade is larger when each country produces goods the other needs (complementarity). If both produce similar goods (cocoa, oil palm) there is little to exchange, reducing trade.
• Nature and cost of transport: the availability, efficiency and cost of road, sea and air transport linking the two countries affects how easily and cheaply goods can be moved, and so the volume traded.
• Government policy and trade barriers: tariffs, import/export duties, quotas, border restrictions and ECOWAS agreements encourage or discourage the flow of goods; free-trade arrangements raise the volume.
• Currency and purchasing power: the exchange rate and convertibility of the naira and cedi, and the level of income/demand in each country, determine how much each can afford to buy.
• Political relations and stability: good, peaceful relations and stable governments promote trade, while political disputes, border closures or insecurity reduce it.

Other acceptable factors: distance between the trading centres, and the size of population/market in each country.

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(a) Outline map of West Africa (features to show)

• (i) Area with less than four months of rain: shade the far north (Sahel/Sahara margin), e.g. northern Mali/Niger/northern Nigeria, where the short rainy season lasts under four months.
• (ii) Area with rainfall all year round: shade the southern coastal belt near the Equator, e.g. the Guinea coast/Niger Delta and the mountains of Cameroon, which have rain in every month.
• (iii) Position of the high-pressure belt in January: draw the continental high pressure (with the ITD/ITCZ pushed south, near the coast) lying over the Sahara in the north, from which the dry north-east trades (Harmattan) blow.

(b) Three reasons for the length of the rainy season in the dry north (a)(i)

• The area lies far inland/far north, away from the sea, so it is reached by the moist maritime south-west monsoon for only a short part of the year.
• The rain-bearing ITD (Inter-Tropical Discontinuity) reaches it only briefly around July-August before retreating southward, giving a short single rainy season.
• For most of the year the dry, dust-laden north-east trade winds (Harmattan) dominate, keeping the area dry and shortening the rains.

(c) Three problems rainfall poses to agriculture in the wet coastal south (a)(ii)

• Heavy, continuous rain causes serious soil erosion and leaching, washing away nutrients and lowering soil fertility.
• Excessive moisture encourages pests, weeds and crop diseases (fungal rots) and hinders the drying and storage of harvested crops.
• Waterlogging and flooding damage crops, and the lack of a dry season makes it hard to grow crops that need a dry spell to ripen and makes farm operations difficult.

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(a) Outline map of Africa: features to locate and name

• (i) Lines: draw the Prime Meridian (0°) and longitude 20°E as vertical lines, and latitude 4°N and latitude 35°S as horizontal lines across the continent.
• (ii) Rivers: mark the Zambezi in south-central/south-east Africa and the Volta in West Africa (Ghana).
• (iii) Mountains: mark Mount Ruwenzori on the Uganda-DR Congo border (equatorial East Africa) and the Atlas Mountains in north-west Africa (Morocco/Algeria).
• (iv) Towns: mark Yaounde (Cameroon, West-Central) and Entebbe (Uganda, on Lake Victoria).
• (v) Man-made lake on the Nile: mark Lake Nasser (behind the Aswan High Dam in southern Egypt).
• (vi) Desert: mark the Namib Desert along the south-west (Atlantic) coast of Namibia.

(b) Four ways the rivers of Africa are important

• Hydro-electric power: rivers are dammed (Volta, Zambezi, Nile) to generate electricity for homes and industry.
• Irrigation and agriculture: river water and flood plains support farming, e.g. the Nile and Niger valleys.
• Transport and trade: navigable stretches provide inland waterways for moving people and goods.
• Water supply and fishing: rivers supply domestic and industrial water, support fishing, and provide tourism/recreation; they also aid national/international communication.

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Contrast between the Sokoto Plains and the Eastern Highlands of Nigeria

(a) Relief and drainage

(b) Resources and human activities

(c) Problems of development

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(a) Outline map of West Africa: minerals, towns and routes

• Diamond: mark the Sierra Leone field (town: Kono/Koidu), with a route to the port of Freetown for export.
• Petroleum: mark the Niger Delta, Nigeria (town: Port Harcourt/Warri), with a pipeline/route to the oil terminals at Bonny/Forcados for export.
• Gold: mark Ghana (town: Obuasi/Tarkwa), with a rail route to the port of Takoradi for export.

(b) One method of mining a named mineral

Petroleum (drilling): after geological and seismic survey locates an oil-bearing structure, a derrick and rotary drill bore a well down through the rock to the oil reservoir. The oil rises up the well under natural pressure (or is pumped) to the surface, is separated from gas and water, and is piped to storage tanks and refineries or export terminals.

(For gold by deep/shaft mining: vertical shafts and horizontal tunnels are sunk to reach the gold-bearing reef, the ore is blasted, brought to the surface, crushed and the gold extracted chemically. For diamond by alluvial mining: gravel is dug from river beds and washed/sieved to recover the stones.)

(c) Four problems associated with mining in West Africa

• Shortage of capital and modern machinery, so mining is often small-scale and inefficient.
• Shortage of skilled/technical manpower, forcing reliance on foreign experts.
• Poor transport and infrastructure from mine to port, and irregular power supply.
• Environmental damage and hazards (land degradation, pollution, mine collapse), plus dependence on unstable world prices and smuggling.

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Ways transportation contributes to the economic development of a country (e.g. Nigeria):

• Movement of raw materials and goods: transport carries raw materials to factories and finished products to markets and ports, keeping industry supplied and reducing costs.
• Opening up of areas / access to resources: roads, railways and waterways make remote regions accessible, allowing mineral, agricultural and forest resources to be exploited and new land to be settled and farmed.
• Promotion of trade: good transport widens the market, links producing and consuming regions, and promotes both internal and international trade, encouraging specialisation.
• Employment and income: the transport sector itself provides jobs (drivers, mechanics, construction workers, port and airline staff) and generates income and government revenue.
• Encourages agriculture and industry: reliable transport allows perishable farm produce to reach markets quickly and lets industries locate efficiently, boosting output.
• Aids other services and national integration: it supports tourism, distribution of social services and the movement of people, and links different parts of the country, promoting national unity and administration.
• Earns foreign exchange: ports, shipping and airlines handle exports and imports and can earn foreign exchange for the economy.

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(a) Distinction between rotation and revolution of the earth

Rotation	Revolution
It is the spinning of the earth on its own axis.	It is the movement of the earth in its orbit around the sun.
The earth turns from west to east.	The earth travels along an elliptical path round the sun.
One complete rotation takes about 24 hours (one day).	One complete revolution takes about 365¼ days (one year).
It is a movement about the earth’s axis.	It is a movement along the earth’s orbit round the sun.
It causes day and night.	It causes the seasons and the varying length of day and night.

(b) Two effects of the rotation of the earth

1. Alternation of day and night: as the earth spins on its axis, the half facing the sun experiences day while the half turned away experiences night, and the two alternate every 24 hours.
2. Deflection of winds and ocean currents (Coriolis effect): the earth’s rotation deflects moving winds and ocean currents (to the right in the Northern Hemisphere and to the left in the Southern Hemisphere) and also produces the difference in local time between places on different meridians.

(c) An eclipse of the sun (solar eclipse)

An eclipse of the sun occurs when the Moon comes exactly between the Sun and the Earth, so that the three bodies lie in a straight line and the Moon’s shadow falls on the Earth, cutting off the sun’s light from part of the earth’s surface. It can happen only at new moon.

Because the Moon is much smaller than the Sun, its shadow has two parts. The dark, cone-shaped inner shadow is the umbra; where its tip touches the earth the sun is completely hidden and observers there see a total eclipse. Surrounding it is the lighter shadow, the penumbra; places within it see only part of the sun covered, giving a partial eclipse. As the Earth rotates and the Moon moves in its orbit, the shadow sweeps across the earth, so the eclipse lasts only a short time at any one place.

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(a) Industrial zones and towns

As shown on the map above, the three major zones of modern manufacturing industries in Nigeria are:

• Lagos-Ibadan industrial zone in south-western Nigeria: Lagos and Ibadan.
• Kano-Kaduna-Jos industrial zone in northern Nigeria: Kano and Kaduna.
• Port Harcourt-Aba-Onitsha industrial zone in south-eastern Nigeria: Port Harcourt and Aba.

These zones developed because they have large markets, better transport links, relatively good electricity and water supply, access to labour, capital, ports or raw materials.

(b) Problems resulting from the concentration of industries in these zones

1. Pressure on social amenities: Heavy industrial concentration places great pressure on electricity, water supply, housing, roads, hospitals and schools.
2. Pollution: Factory smoke, industrial waste, noise and effluents pollute the air, land and water, thereby creating health hazards.
3. Congestion and high cost of living: Industries attract workers and migrants, leading to overcrowding, traffic congestion, high rents, slums and increased pressure on urban land.

(c) Measures for encouraging industries outside these zones

1. Provide basic infrastructure: Government should extend reliable electricity, water supply, roads, rail transport, telecommunications and health facilities to less-industrialised areas.
2. Give investment incentives: Entrepreneurs who establish industries outside the major zones should be offered tax holidays, low-interest loans, grants and subsidised or free land.
3. Establish industrial estates near raw materials: Government can develop industrial layouts and processing centres in other regions, especially near agricultural and mineral raw materials, while improving transport links to markets.

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(a) Characteristics of tropical grassland (savanna) vegetation

• It is dominated by tall grasses (up to 3-4 metres near the forest margin, shorter toward the desert) that turn green in the rains and brown in the dry season.
• Trees are scattered/isolated and short, drought-resistant (xerophytic) and deciduous, with features such as thick bark, small leaves, deep roots and flat crowns (e.g. acacia, baobab, shea).
• Vegetation shows a marked seasonal rhythm, growing luxuriantly in the wet season and drying up, often with bush fires, in the long dry season.
• Grass cover becomes thinner and shorter, and trees fewer, as one moves from the wetter forest edge toward the drier semi-desert margin.
• Trees often occur in gallery (fringing) forest along river banks where water is available all year.

(b) Economic values of savanna vegetation to the inhabitants

• Grazing land: the extensive grasses support cattle, sheep and goat rearing and pastoralism.
• Farmland: cleared and burnt land is used for growing crops such as grains (millet, guinea corn, maize), groundnuts and cotton.
• Timber, fuel and building materials: trees provide firewood, charcoal, poles and thatching grass.
• Economic tree products: shea butter, gum arabic, locust bean and fruits are collected and sold.
• Wildlife and tourism: the open grassland supports abundant game animals, encouraging game reserves, hunting and a tourist industry. It also supports beekeeping/honey collection.

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(a) Vegetation belts in Nigeria

As shown on the sketch map above, the major vegetation belts are arranged broadly from the humid coastal south to the dry northern frontier. Any four of the following are correctly located and named:

• Mangrove swamp forest: found along the Atlantic coast, especially around the Niger Delta and coastal creeks.
• Freshwater swamp forest: found immediately inland of the mangrove belt, particularly in the lower Niger and Niger Delta floodplain.
• Tropical rainforest: found in the southern interior, including parts of Edo, Ondo, Ogun, Cross River, Akwa Ibom and Rivers States.
• Guinea savanna: occupies much of the Middle Belt, north of the forest zone.
• Sudan savanna: found in the northern part of Nigeria.
• Sahel savanna: occurs in the extreme north-east and north-west, close to the borders with Niger and Chad.

(b) Contributions of forest vegetation to the economy of Nigeria

• It provides timber and wood products for building, furniture making, paper production, plywood and fuelwood.
• It provides employment for lumbermen, sawmill workers, carpenters, forest guards, transporters and furniture makers.
• It earns revenue and foreign exchange through the sale and export of timber, logs, wood products and other forest produce.
• It supplies raw materials such as latex, gums, resins, fruits, herbs and medicinal plants for pharmaceutical and other industries.

(c) Problems associated with the exploitation of forest vegetation

• Inaccessibility: Many forest areas are remote, swampy or poorly served by motorable roads, making the evacuation of logs difficult and expensive.
• Mixed or heterogeneous tree species: Valuable trees are often scattered among less valuable trees, so locating and extracting economic species requires more time and money.
• High cost of operation: Forest surveying, purchasing machinery, constructing logging roads, felling trees and transporting logs require large capital investment.
• Danger involved in logging: Tree felling and the use of heavy equipment can cause accidents, injuries and loss of life to forest workers.

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(a) Land and sea breezes

These are local winds caused by the unequal heating and cooling of land and sea. By day the land heats faster than the sea; the warm air over the land rises and the cooler, denser air from the sea blows in to replace it, giving a sea breeze (from sea to land). By night the land cools faster than the sea; the air over the sea is now warmer and rises, so cooler air from the land blows out to sea, giving a land breeze (from land to sea). They are common along coasts and moderate coastal temperatures.

(b) Temperature inversion

Normally temperature falls with height in the lower atmosphere. A temperature inversion is a reversal of this, where a layer of warm air lies above cooler air near the ground, so temperature rises with height. It occurs typically on clear, calm nights when the ground loses heat rapidly by radiation and chills the air just above it, and in valleys where cold, dense air drains down and collects at the bottom. Inversions trap smoke, fog and pollutants near the surface and prevent convection.

(c) Convectional rainfall

Convectional rainfall results from the intense heating of the ground (as in the tropics and in equatorial regions on summer afternoons). The hot surface heats the air above it, which becomes light and rises rapidly by convection. As it rises it cools, water vapour condenses to form tall cumulonimbus clouds, and heavy rain falls, usually in the afternoon and often with thunder and lightning. It is the chief rainfall type near the Equator.

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Explanatory notes on any three of the following:

(a) Government's influence on the location of industries in Tropical Africa

Governments strongly influence where industries are sited. Through industrial policy they establish industrial estates and free-trade zones, grant incentives (tax holidays, cheap land, loans) to firms that locate in chosen areas, and provide infrastructure (roads, power, water). To reduce regional inequality they may deliberately disperse industries to less-developed regions, or site strategic industries (steel, refineries) for political and defence reasons, so factories often locate where the government directs rather than purely on economic grounds.

(b) Nearness to market as a factor of industrial location in Tropical Africa

Industries locate near their markets to cut transport costs and reach consumers quickly. This is important for weight-gaining and perishable/fragile products (soft drinks, bread, furniture) and for industries serving large urban populations. Large towns provide a big, concentrated market and purchasing power, so consumer-goods factories cluster in and around cities such as Lagos, Accra and Kano.

(c) The concentration of manufacturing industries in urban centres of developing countries

Manufacturing concentrates in a few big towns because they offer large labour supply, a big local market, better infrastructure (electricity, water, ports, roads), banking and commercial services, and government offices. Existing industries also attract others (agglomeration/linkage). This leads to over-concentration in a few cities while other regions remain industrially backward.

(d) The predominance of consumer-oriented industries in developing countries

Developing countries are dominated by light, consumer-goods industries (textiles, food and drink, soap, plastics) rather than heavy capital-goods industries. This is because they have limited capital and technology, a shortage of skilled labour, small and low-income markets that demand cheap everyday goods, and a desire to process local raw materials and reduce imports. Such industries need less capital and yield quicker returns.

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(a) Two main types of environmental pollution and causes of one

Two main types are air (atmospheric) pollution and water pollution (others include land/soil pollution and noise pollution).

Three causes of air pollution:

• Burning of fossil fuels in vehicles, power stations and homes, releasing carbon monoxide, sulphur dioxide and smoke.
• Industrial emissions from factories and refineries discharging smoke, soot, dust and toxic gases into the atmosphere.
• Bush burning and gas flaring (and burning of refuse), which release smoke, carbon dioxide and other gases.

(If water pollution is chosen: discharge of industrial effluents/oil spillage into rivers; dumping of untreated sewage and refuse; and run-off of agricultural fertilizers and pesticides.)

(b) Three effects of pollution on man

• Ill-health and disease: polluted air causes respiratory diseases (bronchitis, asthma) and polluted water causes cholera, typhoid and other water-borne diseases.
• Death and shortened life: exposure to toxic gases and contaminated water can cause poisoning and death.
• Loss of livelihood and damage to property: pollution destroys crops, kills fish and livestock, contaminates drinking water and food, and corrodes buildings, reducing income and quality of life.

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(a) Importance of the Aswan High Dam to the Nile Basin

• Hydro-electric power: the dam generates large amounts of electricity for Egypt's homes and industries, promoting industrial development.
• All-year irrigation: stored water in Lake Nasser provides perennial irrigation, allowing two or three crops a year and the reclamation of desert land for farming.
• Flood control: it controls the annual Nile floods, preventing destructive floods in wet years.
• Water storage against drought: the reservoir stores water for use in dry years, giving a reliable water supply.
• Other benefits: improved navigation on the river, a fishing industry on Lake Nasser, and tourism at the dam and lake.

(b) Four problems resulting from the construction of the dam

• Loss of fertile silt: the dam traps silt behind it, so farmland downstream no longer receives the natural fertilising mud and farmers must buy artificial fertilizers.
• Displacement of people and loss of sites: the reservoir flooded land, displacing the Nubian people and threatening ancient monuments (Abu Simbel had to be moved).
• Increased evaporation and salinity/waterlogging: high evaporation from Lake Nasser wastes water, and continuous irrigation causes salinity and waterlogging of soils.
• Spread of disease and coastal erosion: the still water encourages bilharzia (schistosomiasis) and malaria, and the loss of silt has caused erosion of the Nile delta coast and a decline in Mediterranean sardine fishing.

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Explanatory notes on any four of the following:

(a) Cocoa growing in Western Nigeria

Cocoa is the leading cash crop of the south-west (Ondo, Osun, Oyo, Ogun, Ekiti). It thrives on the region's hot, wet climate (over 1200 mm rain), deep well-drained forest soils and shade. It is grown mainly on small peasant farms, takes several years to mature, and the dried beans are a major export earning foreign exchange. Problems include ageing trees, pests/diseases (black pod, capsid) and price fluctuations.

(b) Oil palm production in the eastern states

The oil palm flourishes in the high rainfall and forest soils of the south-east and Niger Delta. It is largely gathered from semi-wild and small-holder groves, yielding palm oil and palm kernel used locally and for export. It provides food, cooking oil, soap-making material and income, but output is limited by reliance on wild palms, low-yielding varieties and simple processing methods.

(c) Rice cultivation in the middle belt

Rice is widely grown in the middle belt (Benue, Niger, Kwara) in river valleys and fadama (flood-plain) land where seasonal flooding provides water. Both swamp (wet) and upland rice are grown, mostly by small farmers. It is a staple food and cash crop, but faces problems of poor water control, pests, and inadequate milling and storage.

(d) Intensive farming in the Kano close-settled zone

Around Kano is one of Africa's most densely populated rural areas, where land is farmed very intensively and continuously. Farmers use manure (from livestock and household refuse), crop rotation, intercropping and permanent cultivation to keep the land productive. Crops include guinea corn, millet, groundnuts, cowpeas and vegetables, often combined with livestock keeping. Pressure on land is high, so holdings are small and every piece of land is used.