WAEC SSCE - Geography - 2004

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The iron and steel industry is most likely to be located near the raw material. This is because iron and steel production requires large quantities of iron ore, coal, and limestone, which are the primary raw materials needed to produce iron and steel. Therefore, it is more cost-effective to establish iron and steel plants in locations where these raw materials are readily available, as transporting them over long distances can be expensive and impractical. Furthermore, the availability of raw materials is also a key determinant in the quality of the final product. Therefore, being close to the source of raw materials ensures that the iron and steel produced is of high quality. Consequently, iron and steel plants are often located near mining areas, where iron ore and coal can be easily sourced, or near coastal areas, where imported raw materials can be easily transported through ports.

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A well will contain water if it is dug below the water table. The water table is the level below the Earth's surface where the ground is saturated with water. When a well is dug below the water table, water will seep into the well from the surrounding soil and rocks. This water will fill up the well, making it a source of water. If the well is dug above the water table, there will be no water to fill it up. However, in some cases, drilling deep enough into the Earth's crust can reach aquifers, which are underground layers of rock or sand that hold water. So, in such cases, drilling a well below the water table or to reach sand bearing water can be necessary to access water.

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The organic components of soil are those derived from living organisms, including plants, animals, and micro-organisms. These components contribute to the formation of humus, which is a dark, spongy material that enriches soil fertility. Animal remains, such as bones and shells, can also contribute to the organic matter in soil as they decompose. Similarly, micro-organisms such as bacteria and fungi play a crucial role in breaking down organic matter into nutrients that can be used by plants. Rock pedestals, on the other hand, are not organic components of soil. They are geological features that are formed by the erosion of soft rock layers, leaving harder rock layers standing as pillars or pedestals. Therefore, the answer is "rock pedestals".

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Down folded layers of chalk or limestone sandwiched between impermeable rock layers and containing trapped water are referred to as artesian formations. An artesian formation is a type of aquifer, which is a layer of rock or sediment that holds water and allows it to flow through it. The water in an artesian formation is under pressure due to the weight of the overlying impermeable rock layer, which forces the water to the surface when a well is drilled. This type of formation is common in areas with folded or tilted rock layers, such as the Great Artesian Basin in Australia, which is the largest artesian basin in the world.

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When two or more towns grow to join each other and still retain their identities, they form a conurbation. A conurbation is a type of urban area where multiple cities, towns, or urban centers grow together and merge into a single continuous urban area. In a conurbation, each of the constituent towns retains its own individual identity and administrative boundaries, but they share common infrastructure, transportation systems, and other facilities. Conurbations are characterized by high population density, economic integration, and social interaction between the constituent towns. Examples of conurbations include the New York City metropolitan area and the Greater London Urban Area.

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The relative advantage of road transport over other modes of transport is its flexibility. This means that road transport can reach almost any location, even remote areas, as long as there is a road network. Unlike other modes of transport that are limited to specific routes, road transport can be directed to any destination as long as there is a road leading there. Additionally, road transport is not limited by fixed schedules and can be customized to meet specific needs of the transporters or the goods being transported. This flexibility makes road transport an ideal mode of transport for short distance travel and for transporting small quantities of goods.

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The correct option is (d), differences in the rate of evaporation, which is not a factor affecting the movement of ocean currents. The movement of ocean currents is primarily driven by the following factors: - Planetary winds: These are the major driving force of ocean currents. The winds move the surface water, which in turn causes a movement of deeper water. - Differences in temperatures: The temperature of ocean water affects its density. Cold water is denser than warm water, so it sinks, while warm water rises. This movement of water, known as thermohaline circulation, drives the ocean currents. - Shape of the land mass: The shape and location of the land masses affect the direction and flow of ocean currents. For example, a narrow strait or passage can cause water to flow faster or slower depending on its shape and width. On the other hand, the rate of evaporation is not a significant factor affecting the movement of ocean currents. Evaporation is the process by which water changes from a liquid state to a gaseous state, and it primarily affects the water cycle on land rather than the ocean currents. Therefore, the correct answer is (d) differences in the rate of evaporation.

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The differential heating of the land and sea results in the phenomenon of land and sea breezes. During the day, the land heats up faster than the sea due to lower specific heat capacity of land. As a result, the air over the land becomes warmer and rises, creating a low-pressure area. The cooler air from the sea then moves in to replace the rising warm air, creating a sea breeze. At night, the land cools faster than the sea, and the warm air rises over the sea to create a low-pressure area. The cool air from the land then moves in to replace the rising warm air, creating a land breeze. This cycle of land and sea breezes helps to moderate temperatures and distribute moisture along coastal areas.

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The description "They are crescentic or moon-shaped and occur individually or in groups" refers to a type of sand dune known as "barchans". Barchans are crescent-shaped dunes formed by the action of wind, which blows sand grains up the gently-sloping windward side and deposits them on the steeply-sloping lee side. They are commonly found in arid regions and can occur singly or in groups.

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The climate of equatorial regions of West Africa is characterized by two rainy seasons with a short dry season in-between. This type of climate is known as equatorial climate, which is typical of areas near the equator. Equatorial climate is characterized by high temperatures and humidity throughout the year, with no distinct winter or summer season. In West Africa, the two rainy seasons occur from April to July and from September to November, with a short dry season in-between. During the rainy seasons, heavy rainfall and thunderstorms are common, while the short dry season is characterized by clear skies and high temperatures. This type of climate supports lush vegetation and is important for agriculture in the region.

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The dry and wet bulb thermometers are used to measure relative humidity, which is the amount of moisture present in the air. When there is a large difference in the readings of the two thermometers, it means that the air is dry because the moisture from the wet bulb evaporates quickly due to low humidity. Thus, it indicates that the relative humidity is low. On the other hand, when the readings are closer, it indicates that the air is more saturated with moisture, and the relative humidity is higher. Therefore, the correct answer is "low."

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Jupiter is the planet that has twelve satellites. A satellite is a celestial body that orbits around a planet, and Jupiter is known to have a large number of satellites. In fact, Jupiter has the largest number of known satellites of any planet in the solar system. As of 2021, Jupiter has 79 known satellites or moons, with the four largest ones called Io, Europa, Ganymede, and Callisto, commonly known as the Galilean moons.

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The Arctic Circle is known as the land of the midnight sun during summer in the Northern Hemisphere. This is because during the summer solstice (around June 21), the sun is visible for 24 hours a day at locations within the Arctic Circle.

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The imports of most developing countries consist mainly of manufactured goods. This is because many developing countries lack the necessary infrastructure and resources to produce their own manufactured goods, such as electronics, machinery, and vehicles. As a result, they rely heavily on imported goods to meet their needs. Furthermore, many developing countries have economies that are heavily dependent on agriculture and the export of raw materials. This means that they may not have the necessary infrastructure or expertise to process these raw materials into finished products. As a result, they often import manufactured goods to satisfy their needs for finished products. It is worth noting that while developing countries do import agricultural raw materials and mineral resources, these tend to make up a smaller portion of their imports compared to manufactured goods. This is because many developing countries have a comparative advantage in the production of raw materials, but lack the necessary infrastructure and expertise to process them into finished products.

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The factor that does not determine the available humus resources in a country is evolution. Evolution refers to the gradual process of change in living organisms over a long period of time, and it does not directly affect the availability of humus resources in a country. On the other hand, births, deaths, and emigration can have an impact on the available humus resources in a country. Humus is a dark organic matter that forms in soil when plant and animal matter decay. The amount of humus in the soil depends on the amount of organic matter that is added to the soil over time. Births, deaths, and emigration can all affect the amount of organic matter that is available to be added to the soil. For example, if there is a high population density and a lot of food waste is produced, this can increase the amount of organic matter available for composting and eventually adding to the soil.

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The seasonal variation in the volume of water in a river is known as its regime. The regime refers to the fluctuations in the discharge or flow of a river throughout the year due to changes in precipitation, temperature, and evapotranspiration. The regime of a river is influenced by the climate and weather patterns of the surrounding area and can have significant impacts on the ecology and human uses of the river. The regime can be classified as perennial (constant flow throughout the year), intermittent (flow only during certain times of the year), or ephemeral (flow only during and immediately after precipitation events).

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The description provided in the statement is a characteristic of coniferous forests. Coniferous trees are usually tall and evergreen, meaning they retain their foliage all year round. The leaves of coniferous trees are commonly small, thick, and leathery, often in the shape of needles, as stated in the statement. These trees are adapted to cold and dry environments and can be found in regions such as northern Europe, Canada, and Siberia. Therefore, the correct option is (b) coniferous forest.

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The process which causes exposed rock surface to break and crumble is known as "weathering". Weathering can be described as the breaking down of rocks, soils and minerals through direct contact with the Earth's atmosphere, water, and biological organisms. Weathering occurs due to mechanical, chemical or biological processes that cause rocks to disintegrate into smaller particles. Mechanical weathering is caused by physical processes such as temperature changes, pressure, and ice wedging, while chemical weathering is caused by chemical reactions that alter the mineral content of rocks. Biological weathering is caused by the activities of living organisms that break down rocks and minerals.

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Winds generally blow from an area of high pressure to an area of low pressure. This is due to the difference in air pressure caused by uneven heating of the Earth's surface by the sun. When air is heated, it becomes less dense and rises, creating an area of low pressure. Conversely, when air cools, it becomes more dense and sinks, creating an area of high pressure. As air moves from high pressure to low pressure, it creates wind. The greater the difference in pressure between the two areas, the stronger the wind will be. This movement of air from high to low pressure is known as the pressure gradient force and is the main driving force of wind.

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Earth movements generate tensional forces that pull the crust apart. Tensional forces are generated when two plates move away from each other, creating a gap or a rift. As the plates move apart, the tension between them causes the crust to stretch and thin, forming a basin or a depression. This can lead to the formation of a rift valley or a mid-ocean ridge. The tensional forces can also cause earthquakes and volcanic eruptions as the magma rises to the surface through the cracks in the crust.

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The part of the earth's crust that is covered by oceans and seas is called the hydrosphere. This includes all the water on the Earth's surface, including oceans, seas, rivers, lakes, and groundwater. The hydrosphere is an important part of the Earth's system and plays a critical role in regulating climate, supporting life, and shaping the landscape through erosion and deposition.

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Three out of the four options provided are true statements about the relationship between the sun and the earth. However, the statement "sun revolves round the earth" is not true. It is the earth that revolves around the sun. This movement of the earth around the sun is what causes changes in the seasons and the length of day and night. The sun's gravitational force is responsible for holding the earth in its orbit and supplying heat and light energy to the earth. The distance from the earth to the sun is approximately 150 million kilometers.

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To calculate population density, we divide the total population of the area by its land area. Population density = Total population / Land area Here, the land area is given as 900,000 square kilometres and the total population is given as 120,000,000. Population density = 120,000,000 / 900,000 Population density = 133.33 persons per square kilometre Therefore, the population density of the area is 133 persons per square kilometre (rounded to the nearest whole number). The closest option is "133 persons per square kilometre".

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The peeling off of the surface layers of rounded boulders during mechanical weathering is called exfoliation. Exfoliation occurs due to the expansion and contraction of rock surfaces caused by temperature changes. During the day, rocks absorb heat from the sun and expand, and at night they cool down and contract. Over time, repeated expansion and contraction cause the outer layers of the rock to peel off in thin sheets. Exfoliation is a common process in areas with extreme temperature variations, such as deserts and mountainous regions.

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The plains formed when the slopes of mountains are worn back in arid and semi-arid regions by mechanical weathering is called pediplains. Pediplains are formed due to the process of mechanical weathering, which involves the physical breakdown of rocks into smaller pieces. In arid and semi-arid regions, the weathering process is accelerated due to the lack of vegetation cover, which protects the rocks from weathering. As the mountains are subjected to mechanical weathering, the loose rock material accumulates at the base of the slopes, forming a gentle slope or a flat plain known as pediplains. These plains have a gently sloping surface and are characterized by a thin layer of soil and gravel. Pediplains are commonly found in arid and semi-arid regions such as the deserts of the southwestern United States and the Sahara Desert in Africa. They are important for agriculture and grazing as they provide a large, flat area for farming and animal husbandry. In summary, pediplains are formed when the slopes of mountains are worn back in arid and semi-arid regions by mechanical weathering. They have a gently sloping surface and are important for agriculture and grazing.

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Laterization is a soil-forming process that is prominent in hot, humid tropics. It occurs in areas with high temperatures and heavy rainfall, where the soils are subjected to intense chemical weathering. Laterization results in the formation of a distinct red-colored soil layer, rich in iron and aluminum oxides. This layer is commonly referred to as the laterite layer, and it is highly leached and infertile due to the loss of nutrients. The process of laterization is driven by the intense rainfall, which leaches the nutrients from the topsoil and transports them downward into the lower layers of the soil. As a result, the laterite layer becomes enriched with iron and aluminum oxides, while the topsoil becomes depleted and infertile. This process of soil formation is important in the tropics because it creates soils that are well-drained, and have good water-holding capacity. However, the infertile nature of these soils presents a challenge to agriculture, and requires careful management and fertilization to support crops.

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The description given, "It is made up of a great variety of evergreen trees, with a distinct layer arrangement" refers to the equatorial forest. The equatorial forest, also known as the tropical rainforest, is a type of forest found around the Equator that experiences high rainfall and has a warm and humid climate. It is characterized by a great variety of evergreen trees, with a canopy layer, understory layer, and forest floor. The canopy layer is the topmost layer that receives the most sunlight, followed by the understory layer, and then the forest floor, which is the lowest layer. The trees in this forest are adapted to the wet and humid environment and many have broad leaves to maximize photosynthesis.

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Lines joining places of equal sunshine duration on maps are known as isohel. Isohel is a type of map that represents the distribution of sunshine duration. These lines connect points on the map with the same amount of sunshine during a specific period of time, usually a day or a year. The term "isohel" comes from the Greek words "iso" meaning equal and "helios" meaning sun. Isohel maps are important for understanding the amount and distribution of solar radiation in different regions, which can have a significant impact on climate, agriculture, and other related fields.

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Market gardening refers to the growing of vegetables around large towns or cities for commercial purposes. Market gardeners typically cultivate small plots of land to produce a variety of fresh fruits, vegetables, and herbs that are sold to consumers in nearby urban areas. This type of farming is usually done on a small scale and requires intensive labor to cultivate and harvest crops. The produce is then sold directly to consumers through farmers markets, roadside stands, or directly to restaurants and grocery stores. Market gardening is an important source of fresh, locally grown produce and provides a means for small-scale farmers to earn a living.

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Marble is a metamorphic rock that is formed from limestone. Limestone is a sedimentary rock that is composed primarily of calcium carbonate. When limestone is subjected to heat and pressure over a long period of time, it undergoes a process of metamorphism, which causes the minerals within it to recrystallize and fuse together. During this process, the original structure of the limestone is altered, and it takes on the characteristic veined and swirled appearance of marble. The high temperatures and pressures cause the calcium carbonate crystals in the limestone to grow larger and interlock with each other, resulting in a much harder and more durable rock than the original limestone. Marble can come in a range of colors, including white, gray, pink, and green, depending on the impurities present in the original limestone. It is a popular building material for its beauty, strength, and versatility.

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Longitude is the measure of distance east or west of the prime meridian (0 degrees longitude). Each 15-degree interval of longitude represents a time difference of one hour. Belfast is located at longitude 6°W, which is 6 x 15 = 90 minutes (1.5 hours) behind Greenwich Mean Time (GMT). Therefore, when it is 10.00am in Belfast, it is actually 10.00am - 1.5 hours = 8.30am GMT. Leningrad is located at longitude 30°E, which is 30 x 15 = 450 minutes (7.5 hours) ahead of GMT. Therefore, when it is 8.30am GMT, it is actually 8.30am + 7.5 hours = 4.00pm in Leningrad. So the answer is 4.00 pm.

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(a) Ways railway transport has contributed to economic development in Tropical Africa:

1. Movement of bulky goods: Railways carry heavy and bulky raw materials such as minerals (copper, coal, tin), timber and agricultural produce cheaply over long distances from the interior to the ports.
2. Opening up of the interior: Rail lines linked landlocked and remote inland regions to coastal ports, encouraging settlement, farming and mining in previously inaccessible areas.
3. Promotion of trade and commerce: By providing regular and relatively cheap transport, railways widened internal and export markets and stimulated buying and selling of goods.
4. Employment generation: Construction, operation and maintenance of railways provide jobs for engineers, drivers, clerks, labourers and traders, raising incomes.
5. Growth of towns and industries: Many towns (e.g. junction and terminal towns) grew along rail routes, and industries were sited near railways to obtain raw materials and distribute finished products.

(b) Ways of improving the development of railway transport in Tropical Africa:

1. Modernisation and expansion: Extend the rail network and construct new standard-gauge lines to link more producing regions, ports and neighbouring countries.
2. Re-equipment: Replace obsolete locomotives, coaches and worn-out tracks with modern engines and stronger rails to improve speed and reliability.
3. Adequate funding: Increase government investment and encourage private and foreign investment (public-private partnership) to finance construction and maintenance.
4. Regular maintenance: Establish workshops and train skilled personnel to service tracks, bridges and rolling stock regularly.
5. Gauge standardisation and inter-country links: Adopt a uniform gauge and connect national railways to promote through-traffic and regional integration.

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(a) Four effects of the revolution of the earth

• The four seasons: as the earth revolves round the sun with its axis tilted, the overhead sun shifts between the tropics, giving spring, summer, autumn and winter in temperate lands.
• Varying length of day and night: at different times of the year, days and nights become unequal in length (long days/short nights in summer and the reverse in winter), except at the equator.
• Changing altitude (apparent movement) of the midday sun: the noon sun is high overhead at some seasons and low at others.
• Occurrence of equinoxes and solstices, and the basis of the calendar year (365.25 days), leading to a leap year every fourth year.

(b) Time calculation

Match starts at 8:00 p.m. local time in Los Angeles (75°W). Find the time in Nigeria (15°E).

Difference in longitude \( = 75^\circ + 15^\circ = 90^\circ \).

\[ \text{Time difference} = \frac{90}{15} = 6 \text{ hours} \]

Nigeria lies east of Los Angeles, so its time is ahead; we add 6 hours:

\[ 8{:}00 \text{ p.m.} + 6 \text{ hours} = 2{:}00 \text{ a.m.} \]

Nigerian fans should switch on their televisions at 2:00 a.m. (the following day).

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(a)(i) Two areas of copper mining in Zambia: the Copperbelt Province towns of Kitwe, Chingola, Mufulira, Ndola and Luanshya, and the newer Solwezi (Lumwana/Kansanshi) area in the North-Western Province.

(a)(ii) One method of copper mining: Open-cast (open-pit) mining is used where the copper ore lies near the surface. The overburden (soil and rock covering the ore) is stripped off with heavy machinery, and the exposed ore is drilled, blasted and loaded onto trucks in a series of descending benches, then hauled to the surface for crushing, concentration and smelting. (Where the ore is deep, underground/shaft mining is used instead.)

(b) Contributions of copper mining to Zambia's economic development:

1. It is the chief source of foreign exchange, earning most of Zambia's export income.
2. It provides government revenue through taxes and royalties used for development.
3. It creates employment for miners, engineers and support workers.
4. It has stimulated growth of towns, railways and industries in the Copperbelt.

(c) Problems facing copper mining in Zambia:

1. Price fluctuations: Falling and unstable world copper prices reduce earnings.
2. Landlocked position: High transport costs to distant seaports raise export costs.
3. Depletion, deep ores and power/water shortages: Rising extraction costs, ore depletion and unreliable electricity hamper production.

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(a) Calculation of the missing percentages

Percentage premium income = \(\dfrac{\text{premium income}}{\text{total premium income}}\times100\).

Motor:

\[\frac{94,442,000}{202,320,000}\times100=46.678\ldots\%\approx \boxed{46.7\%}\]

Miscellaneous:

\[\frac{20,040,000}{202,320,000}\times100=9.904\ldots\%\approx \boxed{9.9\%}\]

Type of insurance	Premium income (₦)	Percentage (%)
Fire	24,532,000	12.1
Accident	13,770,000	6.8
Motor	94,442,000	46.7
Marine	49,536,000	24.5
Miscellaneous	20,040,000	9.9
Total	202,320,000	100.0

Check: \(12.1+6.8+46.7+24.5+9.9=100.0\%\).

(b)(i) Percentage bar graph

The bar represents the whole premium income, that is, \(100\%\). Its sections show the percentage contribution of each class of non-life insurance.

(b)(ii) Disadvantages of a percentage bar graph

1. It shows the relative percentages only; the actual premium incomes in naira cannot be read directly from the graph.
2. Very small component parts are difficult to draw, measure and compare accurately.

(c) Alternative method

A pie chart (divided circle) can be used to represent the statistics.

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(a) Sketch map of Africa showing two important lumbering areas

(b) Factors that promote lumbering in Africa

1. Availability of extensive forest reserves: Equatorial Africa and parts of West Africa have large stands of valuable hardwood trees such as mahogany, ebony and iroko.
2. Favourable hot and wet climate: High temperatures and heavy, reliable rainfall encourage rapid growth of dense tropical forests.
3. Fertile soils: In suitable forest areas, soils support the growth and regeneration of trees.
4. High demand for timber: Timber is needed locally and abroad for building, furniture, paper, plywood and other wood products.
5. Improved transport: Roads, railways, rivers and ports help to move logs from forest areas to sawmills, markets and exporting ports.
6. Establishment of sawmills and wood-processing industries: These provide facilities for converting logs into usable timber and wood products.

(c) Benefits of lumbering in Africa

1. It provides employment for tree fellers, machine operators, sawmill workers, transporters and traders.
2. It earns foreign exchange through the export of logs, sawn timber, plywood and other forest products.
3. It provides revenue to governments through taxes, licences, royalties and export duties.
4. It supplies raw materials for furniture, paper, plywood, carving and other industries.
5. It provides timber for building and construction works.

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Describe the formation and appearance of any two of the following (two are treated here).

(i) Stack

Formation: a stack develops on a headland of fairly resistant rock. Waves attack lines of weakness at the base by hydraulic action and corrasion, first cutting a cave. When two caves on opposite sides of a narrow headland join, or a cave is cut right through, an arch is formed. Continued erosion and weathering widen the arch until its roof becomes too heavy and collapses, leaving an isolated pillar of rock standing in the sea. This is a stack.

Appearance: a tall, steep-sided, isolated column or pillar of rock rising out of the sea just off the coast, separated from the mainland cliff.

(ii) Blow hole

Formation: a blow hole forms where a sea cave is cut into a cliff along a line of weakness (a joint). Waves force water and compressed air up through the joint towards the top of the cliff. Continued hydraulic action enlarges the joint until it breaks through to the cliff top, forming a vertical shaft. During high tides or storms, water is forced up the shaft and spouts out at the surface.

Appearance: a roughly circular opening or hole on top of a cliff, connected below to a sea cave, through which spray and water spout upward with a blowing sound.

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(a) Sketch map of West Africa

The sketch map below shows two ECOWAS coastal countries, two ECOWAS interior countries and the capitals of the four countries.

Key: Ghana and Nigeria are coastal ECOWAS countries. Mali and Burkina Faso are interior ECOWAS countries. The capitals shown are Accra, Abuja, Bamako and Ouagadougou.

(b) Problems facing ECOWAS

1. Poor transport and communication: Inadequate roads, railways, sea links and communication facilities make movement of people and goods between member states difficult.
2. Differences in currencies: The use of different national currencies makes trade and payment between member countries more difficult and costly.
3. Political instability: Coups d'état, civil unrest, wars and insecurity in some member states disrupt regional cooperation and development projects.

(c) Possible solutions

1. Member states should jointly improve roads, railways, ports, air transport and telecommunication links within West Africa.
2. ECOWAS should work towards the adoption of a common currency and harmonised monetary policies.
3. Member states should promote good governance, respect constitutional rule and cooperate in peacekeeping and conflict resolution.

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(a) Four components of soil

1. Mineral (inorganic) matter: weathered rock particles (sand, silt and clay) that form the bulk of the soil and supply nutrients such as potassium, calcium and phosphorus.
2. Organic matter (humus): decomposed remains of plants and animals which give the soil its dark colour, improve fertility and help retain moisture.
3. Soil water (moisture): water held in the pore spaces which dissolves nutrients and makes them available to plant roots.
4. Soil air: gases occupying the pore spaces, supplying oxygen for respiration of roots and soil organisms. (Living organisms such as bacteria, earthworms and fungi are also present.)

(b) The soil profile

A soil profile is a vertical section through the soil from the surface down to the parent rock, showing a succession of layers called horizons.

• O horizon (litter layer): topmost layer of fresh and decaying leaves and organic debris.
• A horizon (topsoil): dark, rich in humus and living organisms; the zone from which minerals are leached downward.
• B horizon (subsoil): lighter coloured zone of accumulation where clay, iron and minerals leached from above are deposited.
• C horizon: partly weathered, broken parent rock (regolith).
• D horizon (bedrock): the solid unweathered parent rock beneath.

See the labelled soil-profile diagram showing these horizons in order from the surface downward.

(c) Three farming practices that lead to soil erosion

1. Bush burning: burning of vegetation before cultivation removes the protective plant cover, exposing bare soil to rain-splash and wind.
2. Overgrazing: keeping too many animals strips the grass cover, loosens the topsoil and allows it to be washed or blown away.
3. Cultivation on steep slopes / ploughing up and down the slope: tilling along the direction of the slope creates channels that guide run-off, accelerating gully and sheet erosion. (Continuous cropping without fallow and shifting cultivation also expose and exhaust the soil.)

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(a) Outline map of Nigeria showing mineral-producing areas and towns

Key to the map:

• Crude oil: Niger Delta, with Port Harcourt shown and named.
• Limestone: Ewekoro area, Ogun State, with Ewekoro shown and named.
• Columbite: Jos Plateau, with Jos shown and named.

(b) Five ways crude oil contributes to the economic development of Nigeria

1. Foreign exchange earnings: Export of crude oil earns foreign exchange for Nigeria.
2. Government revenue: Government obtains revenue from petroleum taxes, royalties, rents and export sales.
3. Employment: It provides direct and indirect employment in exploration, drilling, refining, transport, marketing and related services.
4. Industrial raw material and energy: Petroleum provides fuel for transport and industries and raw materials for petrochemical, fertiliser, plastic and allied industries.
5. Infrastructure and urban growth: Oil revenue finances roads, schools, hospitals, ports, pipelines and other public facilities, while oil activities encourage the growth of towns such as Port Harcourt and Warri.

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(a) Factors which may favour a rapid growth of population

Human factors:

1. High birth rate: Early marriage, polygamy and the desire for large families raise the number of births and speed up growth.
2. Improved medical facilities: Better health care, immunisation and drugs lower the death rate, especially infant mortality, so more people survive.
3. In-migration: The movement of people into an area for jobs, security or better living conditions adds to its population.

Physical factors:

1. Favourable climate: Moderate temperature and reliable rainfall support farming and comfortable living, attracting and retaining people.
2. Fertile soils: Rich soils give good harvests and food security, encouraging settlement and population increase.
3. Availability of water and mineral resources: Adequate water supply and the presence of minerals attract settlers and support economic activity that sustains a growing population.

(b) Problems that may arise from rapid population growth:

1. Food shortage: Population may outstrip food production, leading to hunger and malnutrition.
2. Unemployment: The labour force grows faster than available jobs, causing widespread unemployment and low incomes.
3. Pressure on social amenities: Housing, schools, hospitals, water and electricity become overstretched and inadequate.
4. Environmental problems: Overcrowding, poor sanitation, congestion and pollution increase, and land is degraded through overuse.

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(a) Orographic (relief) rainfall

Orographic rainfall forms when moist air is forced to rise over a highland or mountain barrier. Warm, moisture-laden winds (often from the sea) meet a mountain range and are compelled to rise up the windward slope. As the air rises it cools at the lapse rate; on reaching its dew point the water vapour condenses to form clouds, and heavy rain falls on the windward slope. After crossing the summit, the air descends the leeward slope, warms and dries; this drier region is the rain shadow, which receives little rain.

(b) Convectional rainfall

Convectional rainfall forms through the strong heating of the ground surface. Intense insolation heats the land, which in turn heats the layer of air above it. This warm, moist air becomes lighter and rises rapidly in strong upward (convection) currents. As it rises it cools and condenses, building tall cumulonimbus clouds. When condensation is complete, heavy rain falls, usually in the afternoon and often with thunder and lightning. It is common in the equatorial regions and in the tropics during hot afternoons.

Détails de la réponse

(a) Outline map of Nigeria

Key locations shown: Murtala Muhammed International Airport, Lagos; Mallam Aminu Kano International Airport, Kano; Lagos-Min­na railway line; River Niger; Apapa Seaport, Lagos; and Lokoja River Port.

(b) Economic importance of road transport in Nigeria

1. It conveys agricultural produce, manufactured goods and raw materials from producing areas to markets, factories and ports.
2. It enables the movement of people between homes, farms, schools, offices, hospitals and other places.
3. It promotes domestic trade by linking rural markets with urban commercial centres.
4. It opens up rural and interior areas for development and encourages the establishment of farms, industries and settlements.
5. It provides employment for drivers, mechanics, road construction workers, vehicle dealers and transport operators.
6. It facilitates the movement of services, information, ideas and innovations.

(c) Problems of road transportation in Nigeria

1. Poor condition of roads: Many roads are untarred, narrow or full of potholes, making journeys slow and unsafe.
2. Poor maintenance: Roads, bridges and drainage facilities are often not repaired regularly, so they deteriorate rapidly, especially during the rainy season.

Détails de la réponse

(Country referred to: Nigeria.)

(a) Four factors that promote international trade

1. Differences in natural resources: Nigeria has crude oil, cocoa and solid minerals that other countries lack, while it needs machinery and manufactured goods produced abroad, creating a basis for exchange.
2. Differences in level of industrial/technological development: industrialised nations supply capital goods and technology that developing Nigeria cannot yet produce.
3. Availability of transport and communication links: shipping routes, ports, air links and modern communications make the movement of goods between countries possible.
4. Membership of international/economic organisations: membership of bodies such as ECOWAS, OPEC and the WTO removes barriers and encourages trade. (Others: surplus production for export, favourable government policy and a stable currency.)

(b) Three problems in trade with other West African countries

1. Similarity of products: most West African states export the same primary commodities (cocoa, palm produce, minerals), so they compete rather than complement one another.
2. Poor transport links between the countries: few good roads and railways connect the states, and rivers are interrupted by rapids, making the movement of goods difficult and costly.
3. Multiplicity of currencies and language/colonial barriers: different currencies, exchange controls and English/French divisions hinder smooth payment and dealing. (Also smuggling, trade restrictions and tariffs.)

(c) Three solutions

1. Diversify production so that member states produce different goods that can be exchanged instead of competing.
2. Improve inter-state transport by constructing trans-West African roads and railways and easing border crossings.
3. Adopt a single/common currency and harmonise trade policies (as pursued under ECOWAS) to simplify payments and remove tariff barriers.

Détails de la réponse

(a) Outline map of Nigeria showing cash-crop producing areas and towns

Key: The labelled dots show towns: Akure, Enugu, Kano and Zaria. The shaded or labelled areas show the main producing zones for cocoa, palm produce, groundnut and cotton.

(b) Three major problems of agriculture in Nigeria

1. Inadequate capital and credit facilities: Many farmers cannot obtain sufficient money to buy land, machinery, fertiliser, improved seeds and other farm inputs.
2. Primitive farming methods: The use of hoes and cutlasses on small scattered holdings results in low output and makes mechanisation difficult.
3. Pests, diseases and adverse weather: Insect pests, crop diseases, livestock diseases, drought and floods destroy crops and animals.

(c) Solutions to the problems

1. Government, agricultural banks and co-operative societies should provide farmers with adequate, low-interest loans and subsidies for farm inputs.
2. Farmers should be encouraged to use tractors and other machines, improved seeds, fertilisers and extension services. Land reform and consolidation should also be carried out to reduce fragmentation of farm holdings.
3. Extension officers should educate farmers on the proper use of insecticides, fungicides and veterinary drugs. Irrigation, drainage and flood-control schemes should be developed to reduce dependence on unreliable rainfall.

Détails de la réponse

(a) (i) Annotated cross-profile from A to B

(ii) Points A and B are not intervisible. The intervening hills rise above the line of sight between A and B and therefore obstruct visibility.

(b) Effects of relief on transportation

1. The area is mainly upland; consequently, road construction is difficult and transport routes are few.
2. The rugged hills in the western and northern parts discourage the construction of roads and other transport lines.
3. The less rugged eastern and south-eastern part permits a secondary road, while footpaths are few and widely spaced in the high-relief areas.

(c) Reasons for sparse population

1. The western and northern parts are rugged, high and inaccessible; hence, there are few or no settlements there.
2. Farming is difficult on the high, steep and rugged land, so few people settle in the area.

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(a) Characteristic features of the Tropical Continental (Sudan/Savanna) Climate

• It lies roughly between latitudes 5° and 15° north and south of the Equator.
• Distinct double season: a wet season in the high-sun period and a long dry season in the low-sun period.
• Total annual rainfall is moderate, about 50 cm to 100 cm, decreasing towards the poles/desert margins.
• Rainfall is convectional and falls mainly in one maximum during the wet season.
• Temperatures are high all year, generally 21°C to 32°C, with the hottest period just before the rains.
• The annual temperature range is greater than in the equatorial zone (about 8°C or more).
• Relative humidity is low, especially in the dry season when the dry, dusty Harmattan wind blows.
• Skies are largely clear in the dry season, giving high sunshine and strong evaporation.

(b) Vegetation of the Savanna region

• It consists mainly of tall grasses interspersed with scattered trees, giving a parkland appearance.
• Grasses grow tall (up to 3-4 m) in the wet season and dry up, turning brown, in the dry season.
• Trees are deciduous and drought-resistant, shedding leaves in the dry season to reduce water loss.
• Trees have adaptations to drought and fire: thick, fire-resistant bark, long tap roots, small leathery leaves and umbrella-shaped crowns (e.g. baobab, acacia, shea, locust bean).
• Vegetation is zoned by rainfall: it changes from Guinea savanna (moist, taller trees) through Sudan savanna (shorter grass, fewer trees) to Sahel savanna (thorn scrub) as rainfall decreases polewards.
• Grasses are tufted, growing in tussocks rather than continuous turf.

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(a) What is an environmental hazard?

An environmental hazard is any natural or human-induced event or condition in the environment that poses a threat or danger to human life, property and other living things. It is a situation with the potential to cause damage, injury, loss or destruction.

(b) Five examples of environmental hazards

• Flooding.
• Drought and desertification.
• Earthquakes.
• Volcanic eruptions.
• Soil erosion (also acceptable: landslides, storms/hurricanes, oil spillage, deforestation, pollution).

(c) Three effects of environmental pollution

• Health problems: polluted air and water cause diseases such as cholera, respiratory illness and skin infections, and can lead to death.
• Destruction of ecosystems and living things: pollution kills fish, wildlife and plants, poisons the soil and reduces biodiversity.
• Damage to agriculture and economic loss: contaminated soil and water lower crop yields and fish catch, spoil water supplies and impose high clean-up and treatment costs; air pollution also contributes to global warming and acid rain.