WAEC SSCE - Geography - 1989

Detalhes da Resposta

Diurnal range of temperature refers to the difference between the highest and the lowest temperature during a day. This means that the correct option is "difference between the highest and the lowest temperature for a day". For example, if the highest temperature in a day is 30°C and the lowest temperature is 20°C, the diurnal range of temperature for that day is 10°C. The other options listed are incorrect because: - The average of the highest and the lowest monthly temperature does not give information about the temperature range within a day. - The difference between the maximum and the minimum temperature for a year or a month does not necessarily give information about the daily temperature range. - The average of the minimum and the maximum daily temperature does not provide information about the daily temperature range as it only calculates an average value.

Detalhes da Resposta

Residual mountains are caused by denudation. Denudation is a process that involves the wearing away of the Earth's surface by various agents of erosion, such as wind, water, and ice. Over time, these agents of erosion can remove large amounts of material from the surface of the Earth, including rock and soil. Residual mountains are formed when erosion removes the softer, less-resistant rock layers, leaving behind the harder, more-resistant rock layers. These harder rock layers then form the core of the mountain, while the softer layers are eroded away, creating valleys and other landforms. Examples of residual mountains include the Appalachian Mountains in the eastern United States and the Scottish Highlands in Scotland. These mountains were formed over millions of years through the process of denudation and continue to be shaped by erosion to this day.

Detalhes da Resposta

Air pressure at sea level is higher than at the top of a mountain because the air at sea level has a greater weight. Air has mass and weight, and the weight of the air above us exerts pressure on the surface of the earth. At sea level, the air above us extends all the way to the surface of the ocean, which means that there is a greater weight of air pressing down on us. As we move up a mountain, there is less air above us, so the weight of the air and the air pressure decreases. This is why people often experience difficulty breathing at high altitudes where the air pressure is lower. Therefore, the answer is that air at sea level has a greater weight.

Detalhes da Resposta

The greatest problem to agriculture in the north-eastern part of Nigeria is desert encroachment. Desert encroachment is the process by which fertile land is gradually turned into desert due to natural or human-induced factors such as deforestation, overgrazing, and climate change. In the north-eastern part of Nigeria, desert encroachment has led to the loss of fertile land, reduction in agricultural productivity, and the displacement of farming communities. This has had a negative impact on the livelihoods of farmers in the region, as well as the food security of the country as a whole. Land tenure system, lack of mechanised tools, sparse farming population, and inadequate capital are also important factors that affect agriculture in the region, but they are not as significant as desert encroachment.

Detalhes da Resposta

The question is asking us to identify the statement that is not true of ECOWAS, which means we need to find the statement that does not accurately describe the organization. The answer is "non-payment of annual subvention by any member country leads to loss of membership." This statement is not true. Although annual dues are required from member countries to support the organization's activities, failure to pay these dues does not automatically lead to loss of membership. Rather, the organization may impose sanctions or other penalties on the defaulting member country, but expulsion is not automatic. ECOWAS is an international organization made up of 15 countries in West Africa, and its aim is to promote economic cooperation among member countries. It allows citizens of member countries to stay for at least ninety days within any country, which is intended to promote free movement of people within the region. ECOWAS has been instrumental in promoting regional integration and economic development in West Africa.

Detalhes da Resposta

The textile industry is best located in the northern part of Nigeria because of the availability of cotton. Cotton is the major raw material used in the production of textiles, and the northern part of Nigeria has a conducive climate for cotton cultivation. This makes it easier and cheaper for textile manufacturers to access the raw material needed for their production. In addition, the availability of cotton in the northern region also reduces the cost of transporting raw materials to textile factories, making the production process more cost-effective. Therefore, the availability of cotton is a significant factor in the location of the textile industry in the northern part of Nigeria.

Detalhes da Resposta

The term relative location of a settlement refers to the position of the settlement in relation to other places or landmarks. In other words, it is the location of the settlement relative to other geographical features or human-made landmarks, rather than its exact location on the earth's surface. For example, the relative location of a settlement could be described as being "30 miles south of the nearest city" or "located near a major river." The relative location is important because it helps to provide context and understand the settlement's relationship with other places. It is not related to the nature of the land on which the settlement is located, whether the settlement is inhabited by relatives, an imaginary point on the settlement, or the position of buildings in relation to one another.

Detalhes da Resposta

Detalhes da Resposta

The use of water transport is limited by various factors, including the width of valleys, presence of waterfalls, floating vegetation, seasonality, and narrow gorges. However, the question asks us to identify the exception among these factors, which means we need to find the factor that does not limit the use of water transport. The answer is "wide valleys." Wide valleys actually facilitate the use of water transport because they provide ample space for boats and ships to navigate. In fact, many major rivers around the world, such as the Amazon, Nile, and Mississippi, have wide valleys that have been used for transportation for centuries. On the other hand, waterfalls, floating vegetation, seasonality, and narrow gorges can all make water transport difficult or impossible. Waterfalls and rapids can be dangerous and require portages or other means of bypassing them. Floating vegetation can clog waterways and impede navigation. Seasonality, such as changes in water levels due to drought or flood, can affect the ability of boats to travel. Narrow gorges can make navigation difficult or impossible due to the presence of rocks and other obstacles.

Detalhes da Resposta

Since Tehran (60oE) is ahead of Seoul (150oE) by 90o of longitude, which represents 6 hours of time difference (360o/24 hours = 15o/hour, 90o/15o = 6 hours). If the football match starts at 4p.m on Friday in Tehran, then the time difference between Tehran and Seoul means that it will be 6 hours later in Seoul. Therefore, the commentary of the football match would be heard in Seoul at 10p.m on Friday.

Detalhes da Resposta

Detalhes da Resposta

The best method to check flooding in coastal lowlands is channelisation. This involves the construction of channels or artificial waterways to control the flow of water in a particular area. In coastal lowlands, the land is often flat, and the water from rainfall and other sources may accumulate and cause flooding. Channelisation helps to divert the excess water to a specific location, such as a river or a reservoir. This reduces the risk of flooding and also provides a source of water for irrigation and other uses. Contour ploughing, strip cultivation, terracing, and excavation are all methods used in agriculture to conserve soil and prevent erosion. However, they are not as effective in controlling flooding in coastal lowlands as channelisation.

Detalhes da Resposta

Detalhes da Resposta

Lines of longitude can best be described as imaginary lines on the Earth's surface joining the north and south poles. They are also called meridians. These lines are numbered from 0° to 180°, with the Prime Meridian at 0°, which passes through the Royal Observatory in Greenwich, England. Lines of longitude measure the distance of a place east or west of the Prime Meridian, which is used as the reference line for measuring longitude. The 180° meridian is exactly opposite the Prime Meridian and marks the International Date Line. Each line of longitude is a great circle that runs from the North Pole to the South Pole, cutting the Equator at a right angle. Longitude is an important geographic coordinate that is used to locate positions on the Earth's surface, along with latitude, which measures the distance of a place north or south of the Equator. Overall, lines of longitude help us to navigate and locate places on the Earth's surface, and are an important tool for understanding and studying geography.

Detalhes da Resposta

Koppen's classification of climate is an empirical system based on temperature and precipitation patterns. This classification divides the world's climates into five major groups, which are determined by the annual and monthly averages of temperature and precipitation. The system takes into account factors such as the amount and timing of precipitation, temperature, and the degree of seasonal variation in these factors. It is widely used in the study of climate and helps scientists understand and predict weather patterns in different regions of the world.

Detalhes da Resposta

The statement that best explains the absence or sparsity of undergrowth in the equatorial rainforest is that the taller trees cut off most of the sunlight. The canopy of tall trees in the rainforest is so thick that it blocks most of the sunlight from reaching the forest floor. This lack of sunlight makes it difficult for undergrowth plants to grow, as they require sunlight for photosynthesis. Therefore, the undergrowth in the equatorial rainforest is sparse, and most of the plant life is found in the canopy and understory layers of the forest.

Detalhes da Resposta

The relationship between the elements of an ecosystem is best described as interdependent. This means that the different living and nonliving components of the ecosystem rely on each other for survival and well-being. For example, plants rely on sunlight, water, and nutrients from the soil to grow, while animals rely on plants for food and shelter. At the same time, plants rely on animals to pollinate their flowers and disperse their seeds. Even nonliving components of the ecosystem, such as air and water, are important for the survival of living organisms. Therefore, the relationship between the elements of an ecosystem is not uni-directional or exclusive, but rather multi-directional and interdependent, with each element playing a vital role in maintaining the balance and functioning of the ecosystem as a whole.

Detalhes da Resposta

Detalhes da Resposta

The rocks which do not allow water to pass through them are called impermeable rocks. These rocks have very tiny or no pores, cracks or spaces between the particles that make up the rock, which means that water cannot flow through them easily. This makes impermeable rocks useful for building things like dams or lining ponds to prevent water from leaking out. On the other hand, porous rocks have spaces between their particles, which allows water to flow through them more easily. So, if you want to store water, you would want to use impermeable rocks to prevent it from seeping into the ground.

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

The direction of ocean flow is mainly determined by two factors: prevailing winds and the rotation of the earth. Prevailing winds are the winds that blow most frequently in a particular area, and they exert a significant influence on the surface of the ocean. The rotation of the earth, on the other hand, creates what is known as the Coriolis effect. This effect causes moving objects, including ocean currents, to be deflected to the right in the Northern Hemisphere and to the left in the Southern Hemisphere. As a result, the combination of prevailing winds and the Coriolis effect determines the direction of ocean currents. Other factors such as the shape of the continents, temperature, and depth of the ocean can also affect ocean currents, but prevailing winds and the rotation of the earth are the primary drivers.

Detalhes da Resposta

The world's highest population growth rates are generally recorded by countries that produce inadequate food. This is because, in these countries, the birth rate is high while the death rate is relatively low due to improvements in healthcare and sanitation. As a result, the population of such countries grows rapidly, leading to an increased demand for food, housing, and other basic necessities. However, since these countries produce inadequate food, they may struggle to keep up with the rising demand, leading to issues such as malnutrition and famine.

Detalhes da Resposta

The Benue River provides the longest distance of internal waterways in Nigeria. The Benue River is the largest tributary of the River Niger and is approximately 1,400 kilometers long. It flows from the Adamawa Plateau in northeastern Nigeria and flows westward through the country, eventually joining the River Niger at Lokoja. The Benue River is navigable for approximately 500 kilometers from its mouth, and its navigability provides a significant transportation route for goods and people in Nigeria. The waterway is used for transportation of goods such as agricultural produce, petroleum products, and other goods. It also serves as a source of water for irrigation, fishing, and hydroelectric power generation.

Detalhes da Resposta

Wind erosion is very effective in desert regions because of the combination of two main factors: the lack of vegetation and the arid climate. The desert environment has little to no vegetation cover, and this makes the soil and rocks exposed to the wind, allowing it to act as the only agent of erosion. Additionally, the rocks in desert regions are often soft and less resistant, which means they can be easily eroded by the abrasive action of the wind. Furthermore, there are no large water bodies in desert regions, and rainfall is usually insufficient, leading to high evaporation rates. The lack of water means that there is little to no vegetation cover to protect the soil and rocks from the wind, resulting in more effective wind erosion. Therefore, the lack of vegetation, soft and less resistant rocks, absence of large water bodies, and arid climate make wind erosion very effective in desert regions.

Detalhes da Resposta

Detalhes da Resposta

The statement that is not correct is "igneous rocks occur in layers and contain fossils". Igneous rocks are formed from the cooling and solidification of molten rock material such as lava or magma. They do not occur in layers and they do not contain fossils because they are formed from molten rock, not from the accumulation of organic material. On the other hand, sedimentary rocks are formed by the accumulation and lithification of sediments, and they often contain fossils. Metamorphic rocks are formed from the alteration of pre-existing rocks due to great heat and pressure, and they do not necessarily contain fossils. Basalts are a type of igneous rock that often contain small crystals, while granites are a type of intrusive igneous rock that often contain larger crystals. Sedimentary rocks that are hardened by compression are called sedimentary rocks, not stratified rocks. Calcareous rocks are indeed formed from the remains of living organisms, such as shells or coral reefs.

Detalhes da Resposta

The pair that is not correct in the development of land and sea breeze is "Rainfall with raingauge". A raingauge is a meteorological instrument used to measure the amount of precipitation (rainfall) that occurs over a specific time period and location. The development of land and sea breeze is primarily influenced by differences in temperature between the land and the sea. During the day, the land surface heats up faster than the sea surface, causing the air above the land to rise and the cooler air over the sea to move inland to replace it. This onshore flow is known as sea breeze. At night, the land surface cools faster than the sea surface, causing the air above the land to become cooler and denser, and to move offshore. This offshore flow is known as land breeze. The other options listed are correct instruments used to measure the parameters that affect the development of land and sea breeze. - A hydrometer is used to measure humidity, which is an important factor in the formation of land and sea breeze. - An anemometer is used to measure wind speed, which is an important factor in determining the strength of land and sea breeze. - A thermometer is used to measure temperature, which is the primary driver of land and sea breeze. - A wind vane is used to measure wind direction, which is important in determining the direction of the sea and land breeze. In conclusion, the development of land and sea breeze is not measured with a raingauge, but rather with instruments that measure temperature, humidity, wind speed, and wind direction.

Detalhes da Resposta

The growth of olives in the Mediterranean region of Africa is favoured by cool, wet winters and warm, dry summers. Olives require a specific growing season, and the Mediterranean climate provides the ideal conditions. During the winter months, the temperature is cool, and there is enough rainfall to provide moisture for the trees to grow. In the summer, the temperatures are warm and dry, which allows the olives to ripen and mature. Additionally, the moderately stiff loam or clayey soil found in the Mediterranean region is also suitable for olive growth. High humidity and heavy rainfall are not favourable for olive growth as they can lead to disease and rot. Finally, an abundant supply of skilled labour is important for olive cultivation, but it is not a factor that directly favours the growth of olives.

Detalhes da Resposta

Detalhes da Resposta

Detalhes da Resposta

Jos experiences a moderate temperature compared with other places on the same latitude in Nigeria because it is on a high altitude. As elevation increases, the temperature decreases. Jos is located on the Jos Plateau, which has an average elevation of about 1,200 meters above sea level. This high altitude results in lower temperatures than areas at lower elevations. Therefore, even though Jos is located close to the equator, which typically experiences warm temperatures, its high altitude results in moderate temperatures. Furthermore, the high altitude also results in cooler nights, which makes the climate more conducive for agriculture. The cooler temperatures also make Jos a popular tourist destination, especially during the hot summer months. In conclusion, Jos experiences moderate temperatures due to its high altitude, which results in lower temperatures than other areas on the same latitude.

Detalhes da Resposta

Detalhes da Resposta

The greatest hydro-electricity potential in Nigeria is found in the Niger Benue Trough. This area is known for its numerous rivers, including the Niger and Benue Rivers, which have a combined potential to generate over 5,000 megawatts of electricity. In addition to its abundant water resources, the Niger Benue Trough also has favorable topography for hydroelectric power generation, with steep slopes and gorges that can be used to create waterfalls and dams. While other regions in Nigeria may also have some potential for hydroelectric power generation, the Niger Benue Trough stands out as the most promising area due to its abundant water resources and favorable topography.

Detalhes da Resposta

A good example of the tropical grassland is the vegetation found around Kano in Nigeria. This vegetation is called savanna, which is characterized by grassy plains with scattered trees and shrubs. Savannas are found in tropical regions, where the climate is hot and receives a distinct dry and wet season. In these regions, the high temperatures and seasonal rainfall support the growth of tall grasses and trees with deep roots that can access the moisture beneath the dry surface. The savanna vegetation around Kano is an example of a tropical grassland and is home to many grazing animals, such as antelopes, zebras, and giraffes, as well as predators like lions and hyenas.

Detalhes da Resposta

Detalhes da Resposta

A geographical account of ECOWAS (Economic Community of West African States)

ECOWAS is a regional economic grouping of West African countries. It was established by the Treaty of Lagos on 28 May 1975 to promote economic co-operation and integration among the states of the West African sub-region. Its executive body, the ECOWAS Commission, has its headquarters in Abuja, Nigeria.

(a) Aims and objectives

• To increase and promote trade among the member countries by removing tariffs, quotas and other trade barriers, thereby working towards a common market and a common external tariff.
• To promote co-operation and development in economic activities such as industry, transport, energy, agriculture and telecommunications.
• To co-operate in social and cultural areas such as education, music and art.
• To ensure the free movement of people, goods, services and capital across member states.
• To contribute to a common fund which is used to finance joint projects and to compensate member countries that may lose economically as a result of the integration.
• To raise the standard of living of the people of the sub-region and to achieve collective self-reliance.
• To establish, eventually, a single common currency (the proposed ECO) to ease trade and payments within the region.
• To maintain peace, security and political stability in the sub-region (leading to the formation of the ECOWAS Monitoring Group, ECOMOG).

(b) Membership

ECOWAS is made up of fifteen West African member states, drawn from English-speaking, French-speaking and Portuguese-speaking countries. They are: Nigeria, Ghana, Senegal, Cote d'Ivoire, Mali, Niger, Burkina Faso, Togo, Benin, Guinea, Guinea-Bissau, Sierra Leone, Liberia, The Gambia and Cape Verde. Mauritania, a founding member, withdrew from the organisation in the year 2000. The distribution of the member states across the sub-region is shown on the sketch map below.

(c) Possible solutions to the problems of ECOWAS

• Payment of the annual financial contributions (dues) should be made compulsory, and any member that persistently refuses to pay should be sanctioned or suspended, so that the common fund is well financed.
• Proper orientation and mutual trust among members, with genuine equality in the discussion and formulation of resolutions, so that no country dominates the others.
• A neutral body should be set up to execute the programmes and projects of the organisation impartially, and common funds should be managed honestly.
• The office of the President/Chairman of ECOWAS should be rotated fairly among the Heads of State of the member countries.
• Full and speedy implementation of the protocol on the free movement of persons, goods and services, and improvement of transport and communication links (roads, railways, telecommunications) between member states to boost trade.
• Introduction of a single common currency (the ECO) to facilitate inter-regional trade and payments and to reduce dependence on the currencies of former colonial powers.
• Diversification of member economies so that they produce different, complementary goods rather than competing similar primary exports.
• Maintenance of peace and political stability through bodies such as ECOMOG, since trade and investment can only grow in a secure region.

Detalhes da Resposta

(a) Problems of transportation

(i) The Niger-Benue waterway

• Seasonal fluctuation in water level: the rivers are shallow and non-navigable to large craft in the dry season, restricting use to a few months.
• Sand bars, shoals and rapids: obstacles such as rapids near Jebba and shifting sandbanks interrupt continuous navigation.
• Silting and sediment: heavy deposition reduces depth and needs constant dredging.
• Floating vegetation: water hyacinth and other weeds clog channels.
• Delta problem: a maze of distributaries and a shifting mouth make the lower course difficult to keep open.
• Poor port and handling facilities at river ports, and limited modern craft.

(ii) The Lagos-Kano railway line

• Narrow (single, narrow-gauge) track: a single line causes delays as trains must wait to pass, and the narrow gauge limits speed and load.
• Old and worn equipment: ageing locomotives, wagons and track lead to frequent breakdowns and derailments.
• Slow and infrequent service makes it uncompetitive with road transport.
• Difficult terrain: crossing rivers, the plateau and valleys required costly bridges and gradients that slow trains.
• Poor maintenance and inadequate funding of track and rolling stock.
• Vandalism and theft of rails and fittings, and inadequate feeder links to farms and towns.

(b) Possible solutions

• Regular dredging of the Niger-Benue and clearing of rapids, sandbars and floating weeds to keep channels open all year.
• Construction of dams and barrages to regulate flow and raise dry-season water levels.
• Improve river ports with modern loading, storage and navigational aids (buoys, beacons).
• Modernise the railway: re-lay to standard gauge, double the track on busy sections and replace worn track.
• Buy new locomotives and wagons and set up proper maintenance workshops.
• Provide adequate funding, tighten security against vandalism, and build feeder roads and links to widen the traffic served.

Detalhes da Resposta

Two pairs are chosen: (b) Waterfalls and Gorges and (d) Levees and Deltas. Each pair is described with three main differences and supported by a well-labelled diagram.

(b) Waterfalls and Gorges

(d) Levees and Deltas

Detalhes da Resposta

None

Detalhes da Resposta

Factors limiting industrial development in Tropical Africa

• Shortage of capital: Most Tropical African countries are poor with low savings, so there is little money to build factories, buy machinery and provide infrastructure; they depend on scarce foreign loans and investment.
• Inadequate power supply: Industry needs steady electricity, but many areas (e.g. much of Nigeria and neighbouring states) suffer irregular power and limited energy sources, which discourages factories.
• Poor transport and infrastructure: Bad and insufficient roads, railways, ports and communications make it costly and slow to move raw materials and finished goods, raising production costs.
• Shortage of skilled labour and technical know-how: A high level of illiteracy and few trained engineers, technicians and managers mean industries must import experts, which is expensive.
• Small home market and low purchasing power: Widespread poverty means people cannot buy many manufactured goods, so the market is small and factories cannot produce on a large, cheap scale.
• Competition from imported goods: Cheaper, better-quality manufactured goods from developed countries undersell local products and stifle infant industries.
• Dependence on raw-material export / lack of local raw materials in some areas: Many economies simply export unprocessed raw materials, and some regions lack the varied raw materials needed for manufacturing.
• Political instability and weak policy: Frequent instability, poor planning and inconsistent government policy discourage long-term investment (for example, deterring investors in unstable states).

Any four, well explained with specific examples, are acceptable.

Detalhes da Resposta

Chosen vegetation type: Tropical Rainforest (equatorial forest)

(i) Location

• Found in the low latitudes near the Equator, roughly between 5°N and 5°S.
• Chief areas: the Amazon (Congo) Basin of Central Africa, the Amazon Basin of South America, and South-East Asia (Malaysia, Indonesia); in West Africa it covers the coastal south (including southern Nigeria).

(ii) Vegetation characteristics

• Evergreen - trees keep their leaves all year because growth continues in the hot, wet climate.
• Tall trees arranged in three layers (canopy) - emergent, middle and lower storeys - with a closed canopy shutting out light.
• Great variety of hardwood species (mahogany, iroko, obeche, ebony) mixed together, not in pure stands.
• Lianas (woody climbers), epiphytes and buttress roots are common; the shaded floor has sparse undergrowth except along rivers and clearings.

(iii) Economic importance

• Timber: supplies valuable hardwoods for building, furniture, plywood and export.
• Cash crops: the climate favours cocoa, oil palm, rubber and coffee grown after clearing.
• Forest products: fuelwood, fruits, medicinal plants, rubber latex, bush meat and raffia.
• Employment, foreign exchange, and environmental value - protects soils, stores water, supports research and tourism.

(Either of the other types may be chosen instead: Laurentian - cool temperate eastern margin with mixed coniferous and deciduous forest supporting lumbering, pulp/paper and fur trapping; or Temperate grassland - prairies/steppes/pampas of tall to short grasses supporting extensive wheat farming and cattle/sheep ranching.)

Detalhes da Resposta

None

Detalhes da Resposta

(a) Main features of rotational bush fallowing in West Africa

• The land is divided into several plots; some are cultivated while others are left fallow (resting) so that natural vegetation can regrow.
• Cultivation and fallowing rotate around the plots: after a plot has been cropped for two to three years it is abandoned, and the farmer moves to a rested plot, returning to the first after several years.
• Unlike shifting cultivation, the farmer keeps a permanent homestead and only rotates the farm plots around it.
• The fallow period allows the soil to recover its fertility naturally as vegetation returns nutrients and improves soil structure.
• Simple tools (hoe, cutlass) and family labour are used; farm sizes are small.
• Mixed cropping of food crops such as yam, cassava, maize and vegetables is common.
• Little or no chemical fertiliser is used; soil fertility is restored by the fallow and by ash from burning.

(b) Major factors affecting the practice of bush fallowing

• Population pressure: where population is high, land is scarce and fallow periods are shortened.
• Availability of land: plenty of land encourages longer fallow periods; land shortage discourages the practice.
• Soil fertility: poor tropical soils that lose fertility quickly make fallowing necessary.
• Climate and vegetation: the rate at which bush and grass regrow depends on rainfall and temperature.
• Level of technology: reliance on simple tools and lack of fertiliser makes fallowing the main way of restoring fertility.
• Land tenure system: communal land ownership allows farmers to move around and rest plots.
• Economic level and capital: subsistence farmers who cannot afford fertilisers depend on natural fallow.

(c) Problems associated with bush fallowing

• Shortened fallow periods due to population growth prevent full recovery of soil fertility, leading to declining yields.
• It requires large areas of land, which is wasteful where land is scarce.
• Low productivity means it can support only subsistence needs, not commercial farming.
• Burning of the fallow destroys soil organisms and exposes the soil to erosion.
• Scattered plots make supervision, mechanisation and provision of infrastructure difficult.
• It ties up land that could be used for permanent, more intensive agriculture.
• Continuous cropping when fallow is cut short leads to soil exhaustion and erosion.

Detalhes da Resposta

(a) Diagram showing the four major positions of the earth during its revolution round the sun

The sun is drawn at the centre with the earth shown at four points on its orbit. Throughout the year the earth's axis stays tilted at \(23\tfrac{1}{2}^\circ\) from the vertical (that is, \(66\tfrac{1}{2}^\circ\) to the plane of the orbit) and always points in the same direction in space. The four cardinal positions are the two solstices and the two equinoxes:

• 21 June - Summer Solstice: the North Pole is tilted toward the sun, the overhead (vertical) sun is at the Tropic of Cancer (\(23\tfrac{1}{2}^\circ\)N); longest day in the Northern Hemisphere.
• 23 September - Autumnal Equinox: the axis is sideways to the sun, the overhead sun is at the Equator; day and night are equal everywhere.
• 22 December - Winter Solstice: the North Pole is tilted away from the sun, the overhead sun is at the Tropic of Capricorn (\(23\tfrac{1}{2}^\circ\)S); longest day in the Southern Hemisphere.
• 21 March - Vernal (Spring) Equinox: the axis is again sideways to the sun, the overhead sun is back at the Equator; day and night are equal everywhere.

(b) Effects of the revolution of the earth

1. Change of seasons: Because the tilted axis keeps a fixed direction, each hemisphere is inclined toward the sun for part of the year and away from it for another part, producing the succession of spring, summer, autumn and winter.
2. Varying length of day and night: Away from the Equator the days and nights change in length through the year - long days and short nights in summer, the reverse in winter - while at the Equator they remain nearly equal all year.
3. Changing altitude and apparent migration of the midday sun: The overhead noon sun appears to move to and fro between the Tropic of Cancer and the Tropic of Capricorn, so the noon sun stands higher in the sky in summer and lower in winter.
4. Occurrence of the equinoxes and solstices: The revolution fixes the four cardinal dates (21 March, 21 June, 23 September, 22 December) on which the equinoxes and solstices fall.
5. Periods of continuous day or night near the poles: Beyond the Arctic and Antarctic Circles there are spells of unbroken daylight (midnight sun) and unbroken darkness (polar night).
6. It fixes the length of the year: One complete revolution takes \(365\tfrac{1}{4}\) days; the accumulated quarter-days give an extra day (leap year) every fourth year.

Detalhes da Resposta

The relationship between climate and vegetation in Nigeria

There is a close positive relationship between climate and vegetation in Nigeria. The natural vegetation of any belt depends chiefly on the amount of rainfall it receives, the length of its rainy season and its temperature. Because rainfall is heaviest along the southern coast and decreases steadily northward, the vegetation also changes in step: it grades from dense evergreen forest in the wet south, through the savanna grasslands of the middle belt, to sparse, drought-tolerant scrub in the dry far north. As a result the vegetation belts, like the climate belts, run roughly east to west and succeed one another from south to north.

The two sketch maps below place the climate belts and the vegetation belts side by side. Notice that each vegetation belt occupies almost exactly the same position as the climate belt that produces it.

Map 1 – Climate belts

Map 2 – Vegetation belts

How the belts match, from south to north

Explaining the relationship

• Rainfall is the master control. Where rainfall is heavy and falls for most of the year (the south), trees have enough water all year, so the vegetation is a dense, multi-layered evergreen forest. Along the tidal creeks of the Delta the wettest ground carries mangrove swamp forest.
• As rainfall decreases northward, the forest thins. In the middle belt the total rainfall is lower and a real dry season appears, so tall forest gives way to Guinea savanna – a mix of tall grasses and fire-resistant trees.
• A longer, harsher dry season in the north (with the dry, dusty Harmattan) allows only grasses and scattered thorn trees to survive: this is the Sudan savanna, and in the driest north-east it becomes the open Sahel savanna of short, sparse grass and thorn scrub.
• Temperature and evaporation reinforce rainfall. The hot, dry north loses much water by evaporation, worsening the moisture shortage and favouring drought-tolerant, deep-rooted plants over tall broad-leaved trees.

Conclusion: the heavier and longer the rainfall, the thicker and taller the vegetation. Because rainfall falls steadily from the wet south to the dry north, the vegetation belts change in the same direction – from mangrove and rain forest, through Guinea and Sudan savanna, to Sahel scrub. The two sketch maps therefore show the same belts lying in the same places, proving the direct relationship between climate and vegetation in Nigeria.

Detalhes da Resposta

(a) Three major countries outside Africa that trade with Nigeria

• China, the United States of America, and India. (Others: United Kingdom, Netherlands, Germany, Japan.)

(b) Chosen country: China

(i) Three major products Nigeria exports to China:

• Crude petroleum (oil), liquefied natural gas, and agricultural products such as sesame seeds/cocoa (also solid minerals).

(ii) Three major products Nigeria imports from China:

• Machinery and equipment, electronics and vehicles, and manufactured goods such as textiles and household products.

(c) Two factors responsible for the present pattern of trade

• Difference in level of industrialisation: China is highly industrialised and produces manufactured goods cheaply, while Nigeria is less industrialised and relies on selling raw materials, so Nigeria exports primary products and imports manufactures.
• Nigeria's oil wealth and China's demand for raw materials/energy: China needs energy and raw materials for its industries, and Nigeria has abundant crude oil to sell, so oil dominates Nigeria's exports while it buys finished goods in return.

(d) Two effects of this pattern of trade on Nigeria's economy

• Unfavourable balance of trade / dependence: Nigeria often imports more (and higher-value) manufactured goods than the value it earns, and depends heavily on a single export (oil), so its economy is vulnerable to falling oil prices.
• Weak local industry and loss of jobs: Cheap imported manufactures undersell Nigerian products, discouraging local industry and reducing employment, while the sale of unprocessed raw materials means less value-addition and fewer jobs at home.

(Any listed country may be chosen; products and factors should match that country.)

Detalhes da Resposta

Irrigation agriculture in the Nile Valley (Egypt/Sudan)

(a) Methods of irrigation

• Basin irrigation: low-lying fields are enclosed by earthen banks (bunds); flood water from the annual rise of the Nile is trapped in these basins, allowed to soak the soil and deposit silt, then the surplus is drained off before planting. This is the traditional method.
• Perennial (canal) irrigation: a network of main canals, branch canals and field ditches distributes water throughout the year. Regulators and barrages (e.g. at the Aswan High Dam) store flood water and release it as needed, allowing two or three crops per year.
• Lift irrigation using traditional devices: the shaduf (a counter-weighted bucket on a pole), the sakia (an animal-turned water wheel) and the Archimedean screw (tambour) raise water from the river or canal onto higher fields.
• Modern mechanical pumps driven by diesel or electricity lift large volumes of water from the river and canals to the fields.

(b) Reasons for irrigation agriculture in the Nile Valley

• The region has a hot desert climate with very low, unreliable rainfall, so crops cannot grow on rainfall alone.
• The Nile provides a permanent, reliable supply of water flowing across the desert.
• The annual flood deposits fertile silt (alluvium), producing rich soils that support intensive cultivation.
• High temperatures and abundant sunshine throughout the year allow all-year cropping once water is supplied.
• A large, dense population needs food and cash crops such as cotton, hence the demand for continuous production.

(c) Problems associated with irrigation agriculture in the Nile Valley

• Salinisation: continuous irrigation with poor drainage causes salts to accumulate in the soil, lowering fertility.
• Waterlogging: over-watering raises the water table and floods the root zone, damaging crops.
• Loss of silt: since the Aswan High Dam traps silt in Lake Nasser, downstream fields no longer receive natural fertiliser and farmers must buy expensive chemical fertilisers.
• Spread of water-borne diseases such as bilharzia (schistosomiasis) and malaria, which breed in the standing canal water.
• Silting of canals and reservoirs reduces storage capacity and raises the cost of maintenance and dredging.
• High evaporation losses from canals and reservoirs in the hot desert climate waste water.
• Pests, weeds and disputes over water sharing between countries and farmers also occur.

Detalhes da Resposta

(a) Sketch map of Africa showing the named dams

The outline of the continent is drawn and each dam is marked with a solid dot (●) at its correct position on the river named, then labelled:

• Aswan Dam – on the River Nile in southern Egypt (north-east Africa).
• Owen Falls Dam – on the River Nile where it leaves Lake Victoria, at Jinja in Uganda (East Africa).
• Akosombo Dam – on the River Volta in Ghana (West Africa).
• Kariba Dam – on the River Zambezi, on the Zambia–Zimbabwe border (south-central Africa).
• Cabora Bassa Dam – on the River Zambezi in Mozambique (southern Africa).

(b) Importance of hydro-electric power (HEP) projects to the economy

With reference to specific African examples:

• Provision of electricity for industry: cheap, reliable power drives manufacturing, e.g. the Akosombo Dam on the Volta supplies the VALCO aluminium smelter at Tema in Ghana, so bauxite can be refined locally.
• Domestic and urban power supply: HEP lights homes, offices, schools and hospitals, raising the standard of living, e.g. Owen Falls (Nalubaale) supplies much of Uganda and exports power to Kenya.
• Irrigation and water supply: the reservoirs store water for farmland, e.g. Lake Nasser behind the Aswan High Dam irrigates the Nile valley and permits double-cropping.
• Flood control: the dams regulate river flow and reduce destructive downstream flooding, e.g. Aswan on the Nile and Cabora Bassa on the Zambezi.
• Fishing: the large artificial lakes support commercial fisheries, e.g. Lake Volta and Lake Kariba, providing food and income.
• Tourism and recreation: the lakes and dam walls attract visitors, generating revenue, e.g. Lake Kariba resorts.
• Water transport (navigation): the calm reservoirs serve as inland waterways, e.g. boat services on Lake Volta linking northern and southern Ghana.
• Employment and revenue: construction and operation create jobs and the sale of power earns government revenue.

(c) Problems facing the development of HEP projects in Tropical Africa

• High cost of construction: dams need enormous capital that poor countries lack, forcing reliance on foreign loans and aid.
• Seasonal variation in river flow / water shortage: reduced discharge in the long dry season lowers the water level and disrupts power output.
• Silting of reservoirs: sediment carried by rivers fills the reservoir, reducing storage capacity and shortening the dam’s life.
• High cost of resettlement: flooding large areas displaces people (e.g. over 80,000 resettled for Lake Volta), which is costly and socially disruptive.
• Shortage of skilled labour and technical expertise for building, running and maintaining the plant.
• Mechanical failure and poor maintenance of turbines and equipment interrupt supply.
• Low or scattered demand: a small, dispersed population makes projects uneconomic and long transmission lines expensive.
• Water-borne diseases: the still reservoir water breeds bilharzia (schistosomiasis) and mosquitoes (malaria).
• High evaporation losses from the reservoirs in the hot tropical climate reduce the volume of water available.

Detalhes da Resposta

The answer below describes the North Central Highlands (the Jos Plateau and its surroundings) of Nigeria under the required headings.

(a) Relief

• A high, dissected plateau standing generally between 1,200 m and over 1,800 m above sea level, rising steeply above the surrounding plains through a bounding escarpment.
• The surface is broken by isolated volcanic hills and cones, extinct crater lakes and old lava flows.
• Younger granite masses and inselbergs project above a rolling, undulating upland surface.

(b) Drainage

• The plateau is an important water tower and source region for many rivers, which radiate outward from it.
• Rivers such as the Kaduna, Gongola and headstreams draining to the Benue and to the Niger rise here.
• Streams are fast-flowing with rapids and waterfalls (for example Assop Falls) where they descend the escarpment, giving hydro-power potential.

(c) Soils

• Soils are largely derived from weathered granite and from basaltic (volcanic) material.
• Where formed on lava the soils are dark, deep and comparatively fertile; elsewhere they are shallow, gravelly and leached.
• Extensive tin-mining has disturbed and degraded soils in worked-over areas.

(d) Vegetation

• Cooler, higher rainfall on the plateau supports montane grassland with scattered short trees and shrubs.
• The lower slopes and surroundings carry Guinea savanna woodland.
• Gallery (fringing) forest lines the river valleys.

(e) Human activities

• Mining: the plateau is Nigeria's chief source of tin and columbite.
• Farming: the cool climate favours temperate crops (Irish potatoes, vegetables, wheat) and cereals such as acha, plus livestock rearing on the grasslands.
• Settlement and administration: Jos is the main urban centre.
• Tourism and health resort: the pleasant, cool climate attracts tourists and once served as a rest station.
• Power generation and dairy/ranching: streams and grasslands support hydro-power and cattle rearing.

Detalhes da Resposta

Lumbering in Nigeria

(a) Methods of lumbering

• Selective felling: only mature and commercially valuable trees such as mahogany, iroko, obeche and opepe are cut; young trees are left to grow.
• Felling: trees are cut down with axes, cutlasses, hand-saws and, increasingly, power chain-saws.
• Trimming and cross-cutting: the felled trunk is trimmed of branches and cut into logs of manageable length.
• Log haulage: logs are dragged out of the forest by tractors, caterpillars or human/animal power to a collecting point or roadside.
• Transport to sawmills: logs are moved by lorries, or floated down rivers such as the Niger and Cross rivers, to sawmills and ports.
• Sawing and seasoning: at the sawmill logs are sawn into planks and seasoned (dried) before sale or export.

(b) Problems associated with the exploitation of timber

• Difficult accessibility: dense undergrowth, swamps and lack of roads make it hard to reach and remove timber.
• Heavy weight of logs: hardwood logs are very heavy and some do not float, raising transport costs.
• Scattered occurrence of valuable trees makes selective felling slow and costly.
• Pests and diseases attack the timber and standing trees.
• Rapid deforestation without adequate replanting depletes the forest.
• Shortage of capital and modern machinery, and of skilled labour.
• Poor transport network and bad weather (heavy rains) disrupt operations.

(c) Economic importance of lumbering in Equatorial Africa

• Foreign exchange: export of timber and wood products (e.g. from Nigeria, Zaire/DR Congo, Gabon) earns foreign currency.
• Employment: provides jobs for fellers, sawmill workers, transporters and traders.
• Raw material for industries: supplies timber for construction, furniture, plywood, paper and matches.
• Government revenue through royalties, licences and taxes.
• Development of infrastructure: roads and railways built for logging open up the interior.
• Local needs: supplies fuel-wood, building poles and materials for the local population.
• It stimulates the growth of allied industries such as furniture-making and paper-milling.

Detalhes da Resposta

(a) Functions of urban and rural settlements

Functions of urban settlements (towns/cities):

• Administrative - centres of government and public offices.
• Commercial and industrial - centres of trade, banking, markets and manufacturing.
• Service centres - provide higher education, specialist hospitals, transport hubs, and recreation.

Functions of rural settlements (villages):

• Agricultural production - main centres of farming, livestock keeping, fishing and forestry.
• Supply of food and raw materials to the towns.
• Source of labour and preservation of traditional/cultural life; some carry out mining or local crafts.

(b) Three areas of interdependence between rural and urban settlements

• Supply of food and raw materials vs manufactured goods: Rural areas produce food and raw materials for the town, while the town supplies the village with manufactured goods (tools, cloth, fertiliser) and processed products.
• Labour and employment: Rural areas supply workers (migrants) to urban industries and services, and towns provide jobs and wages, some of which are sent home to support rural families.
• Markets and services: The town is a market where villagers sell produce and buy goods, and it provides higher services (hospitals, schools, banks, administration) used by rural people; in turn the rural area is a market for the town's goods.

(Also acceptable: movement/transport links, and the town as a source of ideas, technology and credit for the countryside.)

Detalhes da Resposta

(a) Economic importance of rocks

• Source of building materials: Granite, limestone, sandstone and gravel are quarried for construction of houses, roads and bridges; limestone is the raw material for cement.
• Source of minerals and ores: Rocks contain valuable metallic and non-metallic minerals (iron ore, tin, gold, copper, coal, petroleum) that support mining industries and exports.
• Formation of soils for agriculture: The weathering of rocks produces the soils on which crops are grown, and some rocks (e.g. volcanic) give very fertile soils.
• Source of energy and industrial raw materials: Coal, petroleum and natural gas found in sedimentary rocks provide fuel and power; other rocks supply raw materials for glass, ceramics and chemical industries.
• Underground water and tourism/employment: Porous rocks store underground water (aquifers) tapped by wells; striking rock scenery attracts tourists, and quarrying and mining create employment and revenue.

(b) Characteristics and mode of formation of igneous rocks

Mode of formation: Igneous rocks are formed from the cooling and solidification of molten material (magma below the surface or lava on the surface).

• Intrusive (plutonic) rocks form when magma cools slowly deep underground, allowing large crystals to grow (e.g. granite).
• Extrusive (volcanic) rocks form when lava cools quickly at the surface, giving small or fine crystals (e.g. basalt).

Characteristics:

• They are crystalline, made of interlocking crystals; slow cooling gives large crystals, fast cooling gives fine ones.
• They are usually hard and non-porous, and generally lack stratification (no layers).
• They contain no fossils, because they solidified from molten material.
• They occur in masses such as batholiths, dykes and sills, and many are resistant to weathering.

Detalhes da Resposta

The Tropical Monsoon climatic region

(a) Climate

• High temperatures all year (about 24-30°C), with the hottest period just before the rains break.
• A marked wet and dry season controlled by reversing monsoon winds: the on-shore south-west monsoon in summer brings very heavy rain, while the off-shore north-east winds in winter give a dry season.
• Very heavy annual rainfall (often over 2000 mm), concentrated in the summer months, sometimes with relief rainfall on windward coasts.

(b) Vegetation

• Monsoon (tropical deciduous) forest: trees shed their leaves in the dry season to reduce water loss, unlike the evergreen equatorial forest.
• Valuable hardwoods such as teak and sal, with bamboo thickets; the forest is less dense and more open than equatorial rainforest.
• Where rainfall is lower it grades into tall grassland with scattered trees.

(c) Human activities

• Intensive wet-rice cultivation on the plains and deltas, which support dense farming populations.
• Growing of other crops such as cotton, jute, sugar cane, tea and spices, and rearing of cattle.
• Lumbering of teak and other hardwoods, and processing/industries based on the farm and forest products; fishing along the coasts.

(Alternatively, the Cool Temperate Western Margin (British type) may be described: mild winters and cool summers, rain all year with a winter/autumn maximum from westerlies and depressions; natural deciduous woodland (oak, beech, ash); mixed farming, dairying, fishing, industry and dense urban settlement.)

Detalhes da Resposta

Industrial location is controlled by the pull of raw materials, power, market, labour, transport and government policy. Any three of the following are required.

(a) Textile mills in Kaduna

• Raw material: ready supply of cotton from the surrounding Northern savanna belt (Kaduna, Zaria, Katsina, Kano areas).
• Power: access to electricity from the national grid and nearby Kainji/Shiroro hydro-power.
• Water: the River Kaduna provides the large volumes of soft water needed for washing, dyeing and finishing cloth.
• Labour: abundant cheap labour from the densely populated North.
• Market: large local and national demand for cloth and clothing.
• Transport: the Lagos-Kano railway and trunk roads pass through Kaduna, easing movement of cotton in and cloth out.
• Government policy: deliberate siting of textile industries in the North to develop the region.

(b) Oil refinery in Warri

• Raw material: nearness to the Niger Delta crude-oil fields, so crude is piped over a short distance.
• Transport of product: coastal/creek location gives access to the sea for tanker export and coastal distribution; pipelines link it to depots.
• Water: abundant water from the delta creeks for cooling and processing.
• Land: availability of extensive, cheap swampy land for the large plant and storage tanks.
• Market: supplies petroleum products to the industrial south and beyond.
• Government policy: federal decision to refine crude locally rather than export it all.

(c) Pulp and paper mill in Oku Iboku

• Raw material: location within the rain-forest belt of the Cross River basin supplies timber and fast-growing gmelina plantations for wood pulp.
• Water: the Cross River provides the very large volumes of water pulping and paper-making require, and a means of moving logs.
• Power: supply of electricity from the grid.
• Transport: river and road links for bringing in wood and taking out paper.
• Market: national demand for paper and packaging materials.
• Government policy: siting an import-substitution paper industry to save foreign exchange.

(d) Cement factory in Ewekoro

• Raw material: the factory sits directly on massive limestone deposits, the chief raw material for cement; clay and shale are also locally available.
• Market: nearness to Lagos, Ibadan and Abeokuta, a large and growing construction market.
• Transport: good road and rail links to the coastal cities for distributing the bulky, heavy product.
• Power and labour: grid electricity and available labour from the densely settled south-west.
• Land: availability of land for quarrying and the plant.

Detalhes da Resposta

(a) Outline map of Nigeria

The map below shows the required rivers, lakes, highlands and lowland regions correctly located.

What is shown on the map:

• Rivers: the Niger (entering in the north-west, flowing south-east through Kainji and Jebba to the confluence at Lokoja, then south to the delta); the Benue (entering from the east and joining the Niger at Lokoja); the Sokoto (in the north-west, a tributary of the Niger); the Cross (in the south-east, draining to Calabar); and the Ogun (in the south-west, draining towards the Lagos lagoon).
• Lakes: one natural lake - Lake Chad (far north-east); and one artificial lake - Lake Kainji (the reservoir behind Kainji Dam on the River Niger).
• Highlands: the Jos Plateau (central Nigeria), the Udi Hills (near Enugu in the south-east), the Western Highlands (the Yoruba uplands of the south-west) and the Obudu Plateau (on the eastern border near Cameroon).
• Lowlands: the Sokoto Plains (a lowland region in the north) and the Niger Delta / coastal lowland (in the south).

(b) Importance of the River Niger to the economy of Nigeria

1. Generation of hydro-electric power (HEP): dams on the river at Kainji, Jebba and Shiroro generate a large part of Nigeria’s electricity, which powers homes and industries.
2. Inland water transport: the river serves as a natural waterway for moving people and goods by boat and barge, linking river ports such as Onitsha, Lokoja and Baro.
3. Irrigation: its water is used to irrigate farmlands in the dry season, supporting schemes such as the Bacita sugar and rice projects, thereby increasing food production.
4. Fishing: the river supports a thriving fishing industry that supplies protein food and income to riverine communities.
5. Employment: it provides jobs for fishermen, boat operators, dam and irrigation workers, and traders along its banks.
6. Domestic and industrial water supply: the river supplies water for household use and for factories located near it.
7. Tourism and recreation: the Kainji Lake and its National Park attract tourists, earning revenue for the country.
8. Source of building materials: sand and gravel are dredged from the river for the construction industry.

Detalhes da Resposta

Reasons for the high population growth rates in developing countries

Population growth depends on the balance between the birth rate and the death rate. In developing countries the birth rate stays high while the death rate has fallen sharply, giving rapid natural increase.

• High birth rate: Fertility is high because of early marriage, limited use of family planning, and the desire for large families.
• Falling death rate through better medicine: Improved health care, immunisation, drugs and control of diseases have greatly reduced deaths, especially infant mortality, so more children survive.
• Children seen as an economic asset: On farms children provide labour and are expected to care for parents in old age, encouraging couples to have many.
• Religious and cultural beliefs: Some beliefs and traditions favour large families and discourage birth control, and a man's status may be linked to the number of his children.
• Improved food supply, water and sanitation: Better nutrition and clean water have lowered deaths from hunger and disease, raising life expectancy.
• High illiteracy and low status of women: Where education, especially of women, is low, family-planning knowledge is limited and women marry young and bear more children.
• Young age structure: Because past growth was high, a large share of the population is young and entering child-bearing age, so births remain high (population momentum).

Together these keep births high while deaths fall, producing the rapid population growth typical of developing countries.