WAEC SSCE - Geography - 2010

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The process of providing water to farmlands in areas with insufficient rainfall is known as irrigation. It involves the artificial distribution of water to crops using channels, pipes, or other methods. The goal of irrigation is to ensure that crops have enough water to grow and develop properly. This is particularly important in arid or semi-arid regions where natural rainfall is not sufficient for agriculture. By providing water to crops through irrigation, farmers can increase their yields and improve food security.

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The northeastern seaboard of the USA has a very dense population. This region, also known as the Northeast Megalopolis, is a heavily urbanized area that includes cities such as New York, Boston, and Philadelphia. It is home to over 50 million people and is one of the most densely populated regions in the world. The Northeast Megalopolis has a long history of industrialization and urbanization, which has contributed to its high population density. Additionally, the region has a highly developed transportation infrastructure and is a center for commerce, finance, and culture, which attracts people from all over the world.

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The part of the lithosphere which forms the ocean floor is called "sima." The lithosphere is the outermost layer of the Earth, which includes the crust and the uppermost part of the mantle. The crust can be divided into two parts: sial and sima. Sial refers to the continental crust, which is primarily composed of lighter, less dense rocks such as granite. Sima, on the other hand, refers to the oceanic crust, which is primarily composed of heavier, more dense rocks such as basalt. The ocean floor is made up of sima, which is formed by volcanic activity at mid-ocean ridges. As magma rises to the surface, it cools and solidifies to form new oceanic crust. Over time, the ocean floor spreads out as new crust is formed at the ridges and older crust is pushed away from the ridge and subducted back into the mantle at deep-sea trenches. In summary, the part of the lithosphere which forms the ocean floor is sima, which is the part of the crust primarily composed of heavier, more dense rocks such as basalt.

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A true bearing is the angle between the direction of an object from the observer's position and the direction pointing towards True North. True North is the direction towards the geographic North Pole, and it is not affected by magnetic variation, which is the angle between magnetic North and True North. Magnetic North is the direction towards the Earth's magnetic North Pole, which is not located at the geographic North Pole. Therefore, a true bearing is not affected by magnetic variation, but it is important to take magnetic variation into account when using a compass to determine a magnetic bearing. The Southern Hemisphere is a geographic region and is not directly related to the concept of true bearing.

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The true characteristic of sedimentary rocks is that they are laid down in strata. Sedimentary rocks are formed through the accumulation and lithification (compaction and cementation) of sediment, which may come from weathering and erosion of pre-existing rocks, or from the remains of plants and animals. As the sediment settles, it forms layers, or strata, which are often visible in the rock. These layers can provide important information about the history of the area, including changes in the environment, climate, and sea level. Sedimentary rocks can include a variety of rock types, such as sandstone, shale, limestone, and conglomerate. They can be found all over the world and are often used as building materials, such as in construction of buildings and roads.

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Since the time at Point X is noon, we can assume that it is at the Prime Meridian (longitude 0). This means that for every 15 degrees of longitude, there is a time difference of one hour. If it is 10.00 pm at Point Y, this means that there is a time difference of 10 hours from Point X. Therefore, we can calculate the longitude difference between Point X and Point Y by multiplying the time difference by 15 degrees per hour: 10 hours * 15 degrees per hour = 150 degrees Since Point X is at longitude 0, we can find the longitude of Point Y by adding the longitude difference: 0 degrees + 150 degrees = 150 degrees East Therefore, the answer is: 1500E

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The correct answer is attrition. Attrition is a physical weathering process that occurs when rocks are broken down into smaller pieces through abrasion, collision, or friction. On the other hand, the other options listed are all processes of chemical weathering, which involves the breakdown of rocks through chemical reactions with water, air, or other substances. For example, oxidation is the reaction of oxygen with minerals in rocks to form oxides or rust, hydration involves the reaction of water with minerals to form new compounds, and carbonation is the reaction of carbon dioxide with water to form carbonic acid, which can dissolve certain types of rocks.

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The fold mountains found in Africa is the Atlas Mountains. The Atlas Mountains are a range that stretches across three countries: Morocco, Algeria, and Tunisia. They extend for about 2,500 km (1,600 miles) through these countries, with their highest peak reaching 4,167 meters (13,671 feet) in elevation. The Atlas Mountains were formed by the collision of the African and Eurasian tectonic plates and are a relatively young mountain range compared to other major ranges in the world.

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The northern and southern limits of the apparent movement of the sun are marked by the Tropics of Cancer and Capricorn. These are imaginary lines located at 23.5 degrees north and south of the equator, respectively. The Tropic of Cancer marks the northernmost point where the sun appears directly overhead during the summer solstice in the northern hemisphere, while the Tropic of Capricorn marks the southernmost point where the sun appears directly overhead during the summer solstice in the southern hemisphere. These lines also mark the limits of the tropical zone, where the climate is generally hot and humid.

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The statement best describes sea transport. Sea transport is the slowest and cheapest means of transportation and is ideal for transporting large quantities of bulky goods over long distances between countries. It involves the movement of goods and people by sea using ships or boats. Sea transport is suitable for the transportation of heavy and bulky goods such as machinery, automobiles, and minerals. It is also an efficient way to transport goods between countries as it can carry a large amount of cargo at once.

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The most important active factor of soil formation is climate. Climate affects soil formation by influencing the rate and type of weathering, organic matter accumulation, and leaching. Temperature and precipitation are the two key elements of climate that influence soil formation. High temperature and rainfall increase the rate of weathering, while cold temperatures slow it down. Additionally, high rainfall promotes leaching and organic matter accumulation, resulting in thicker and darker soils. Hence, climate is considered the most important factor affecting soil formation.

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The best explanation for the influx of refugees from Liberia to Ghana is the great suffering in Liberia from ethnic tension and civil war. Between 1989 and 2003, Liberia experienced two devastating civil wars that left hundreds of thousands of people dead and displaced millions more. The wars were fueled by ethnic tensions and political instability, and they caused widespread suffering and displacement. Many Liberians fled their homes and sought refuge in neighboring countries, including Ghana. Ghana has a history of welcoming refugees and providing them with assistance and support. During the Liberian civil wars, Ghana provided shelter, food, and medical care to thousands of Liberian refugees who had fled the violence and instability in their own country. Therefore, the correct answer is "great suffering in Liberia from ethnic tension and civil war".

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The most important trading partner of Anglophone West African Countries is the "United Kingdom." This is because most of these countries were colonized by the British, and they have maintained strong economic ties with the UK even after gaining independence. The UK is a major importer of West African products such as oil, cocoa, and minerals, and it also exports a variety of goods and services to the region. Additionally, the UK has historical, cultural, and linguistic ties to Anglophone West Africa, which further strengthens the trade relationship between the two regions.

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The study of the continuous interaction between living things and their environments is known as ecology. Ecology is a branch of biology that focuses on the study of living organisms and their interactions with each other and their physical environment. It encompasses various aspects such as the study of ecosystems, biotic and abiotic factors that affect living organisms, energy flow, nutrient cycling, and biodiversity. Ecologists study the relationships between living things and their environment to better understand how different species interact with each other and how they are affected by changes in their environment, such as climate change or human activities.

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The form of precipitation that is not included in the given options is "dust". Precipitation refers to any form of water that falls from the atmosphere and reaches the surface of the Earth. This can include rain, snow, sleet, and hail, all of which are forms of water in different states. Hail is a type of precipitation that falls as small pellets of ice during thunderstorms. Snow is another type of precipitation that forms when water vapor in the atmosphere freezes and falls to the ground as ice crystals. Dew, on the other hand, is not considered a form of precipitation because it does not fall from the atmosphere. Rather, it forms when water vapor condenses on surfaces during the night when the temperature drops. Finally, dust is not considered a form of precipitation because it is not made of water. Rather, it consists of tiny particles of soil, dirt, and other materials that are blown around by the wind. While dust can fall from the atmosphere and settle on surfaces, it is not classified as a form of precipitation. Therefore, the correct answer is "dust".

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The statement describes the equatorial climate. This climate is characterized by high temperatures, high humidity, and heavy rainfall throughout the year. The temperature remains fairly constant, with small variations due to altitude. The equatorial climate is usually found in areas close to the equator, such as Central Africa, the Amazon basin, and parts of Southeast Asia.

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A great circle is the largest circle that can be drawn on a sphere, and its center coincides with the center of the sphere. It is formed by the intersection of the sphere with a plane that passes through the center. The only line among the options that is a great circle is the Equator, which is the largest circle that can be drawn around the Earth, dividing it into two hemispheres: the Northern Hemisphere and the Southern Hemisphere. The Tropic of Cancer, Tropic of Capricorn, and Arctic Circle are all smaller circles that can be drawn around the Earth, and are therefore not great circles.

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One of the major problems of manufacturing industries in Tropical Africa is inadequate raw materials. Raw materials are the basic materials that are used in the production of goods. Inadequate raw materials can hinder the smooth functioning of manufacturing industries, especially in tropical Africa where there may be limited access to certain raw materials needed for manufacturing. This can result in a higher cost of production and the need to import raw materials, which can further increase costs and reduce competitiveness. Additionally, inadequate raw materials can limit the range of products that can be manufactured and lead to a heavy reliance on a few products, which can be risky for the long-term sustainability of the industry.

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The role of transport in economic development of any nation includes several factors that promote economic growth and development. These include the movement of goods and services, the opening up of new lands and areas, and the provision of employment. However, national disintegration is not a major benefit of transport. Rather, transport helps to connect and unify different parts of a nation, which can promote social and economic cohesion. Therefore, the correct answer to the question is "national disintegration."

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Nature mostly intervenes in the state of balance in land ecosystem through climatic change. The balance in a land ecosystem is determined by a delicate interplay between various living and non-living components. These include plants, animals, soil, air, water, and sunlight. Any change in one of these components can affect the balance of the entire ecosystem. Climatic change is one of the major factors that can disrupt the balance of a land ecosystem. Changes in temperature, rainfall, and other climatic conditions can affect the growth and reproduction of plants and animals, alter the composition of soil and water, and impact the overall productivity of the ecosystem. This can lead to a cascade of effects, causing changes in food chains, biodiversity, and even the physical structure of the ecosystem. Thus, climatic change can have significant impacts on the functioning and stability of land ecosystems.

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The landform that is not produced by faulting is a sill. Sills are horizontal intrusions of magma that solidify between layers of sedimentary or volcanic rock. They are not formed by faulting, which occurs when rocks along a fault line move relative to one another due to tectonic forces. On the other hand, a fault scarp is a cliff or steep slope that is created by the displacement of rock along a fault line. A rift valley is a lowland region that forms between two diverging tectonic plates. A horst is a raised block of land that is bounded by normal faults. Therefore, the correct answer is sill.

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The process of removing soluble substances such as mineral salts from the topsoil into lower layers of the soil is called "leaching." This process occurs when excess water, often from rainfall or irrigation, moves through the soil, carrying with it the dissolved minerals and nutrients. These soluble substances are transported downwards and deposited in the lower layers of the soil, making them less available to plant roots in the topsoil. This can have both positive and negative effects on plants and the environment. While leaching can help to prevent the accumulation of excess nutrients, it can also lead to a loss of valuable minerals from the topsoil, reducing soil fertility and plant growth.

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Lumbering, also known as logging or timber harvesting, is the process of felling trees and processing them into timber and other wood products. One outstanding benefit of lumbering to an economy is that it earns foreign exchange. This is because timber and wood products can be exported to other countries, generating revenue and boosting the country's foreign exchange reserves.

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Lumbering, also known as logging, is a very important activity in Liberia. Liberia is a country in West Africa with abundant forests covering over 45% of its land area. The country's forest resources are a vital source of livelihood and income for many Liberians, as well as a key contributor to the country's economy. The forests of Liberia are home to a wide variety of plant and animal species, some of which are unique to the region. However, unsustainable logging practices have led to deforestation and environmental degradation in the country. The Liberian government and international organizations are working to promote sustainable logging practices and protect the country's forest resources.

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The smallest ocean in the world is the Arctic Ocean. It is located in the northern hemisphere and is surrounded by parts of Europe, Asia, and North America. It covers an area of approximately 14.05 million square kilometers, which is about 3.5% of the total area covered by all the oceans on Earth. The Arctic Ocean is much smaller than the other major oceans, such as the Pacific and the Atlantic, which both cover much larger areas. The Indian Ocean is also larger than the Arctic Ocean. However, despite its relatively small size, the Arctic Ocean is an important body of water that plays a crucial role in regulating the Earth's climate and supporting a unique ecosystem of plants and animals. Therefore, the correct answer is the Arctic Ocean.

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The statement describes the tropical rain forest. Tropical rain forests are dense and luxuriant forests that are characterized by high rainfall, high humidity, and high temperatures throughout the year. These forests contain a great variety of plants, including broad-leaved trees, and are home to a wide variety of animal species. They are found in tropical regions around the equator, and are one of the most biologically diverse ecosystems on the planet.

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The correct order of increasing settlement size is: isolated farmstead - hamlet - village - town. An isolated farmstead is a single farm or homestead that is located in a remote or isolated area, often without any nearby settlements. A hamlet is a small settlement that consists of a few houses, and it usually lacks the basic amenities like schools, hospitals, and markets. A village is a larger settlement than a hamlet, and it usually has a population that ranges from a few hundred to a few thousand people. A village has basic amenities like schools, hospitals, and markets, but it may not have more advanced facilities like a large hospital or a university. A town is a larger settlement than a village, and it usually has a population that ranges from a few thousand to tens of thousands of people. A town has more advanced amenities and facilities than a village, such as large hospitals, universities, and shopping centers. Therefore, the order that represents an increasing order in the size of settlement is isolated farmstead - hamlet - village - town.

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Cameroun is not a member of ECOWAS. ECOWAS stands for Economic Community of West African States, and it is a regional intergovernmental organization that was established to promote economic cooperation and integration among its member states in West Africa. Although Cameroun is located in West Africa, it is not a member of ECOWAS. Instead, Cameroun is a member of the Central African Economic and Monetary Community (CEMAC), which is a regional organization that promotes economic integration and cooperation among its member states in Central Africa. In summary, Nigeria, Ghana, and Liberia are members of ECOWAS, while Cameroun is not a member of this organization.

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Lumbering, which is the commercial cutting and harvesting of trees for timber, is an important economic activity in the tropical rainforest vegetation belt. The tropical rainforest is a dense forest characterized by tall trees and a diverse range of flora and fauna. The region is home to a variety of tree species, including hardwoods like mahogany, teak, and rosewood, which are highly valued for their durability and beauty. Lumbering is a major economic activity in the region, as the timber is used for a variety of purposes such as construction, furniture making, and paper production.

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The option that is not a major benefit of savanna vegetation is "aqua culture". Savanna vegetation is a type of grassland with scattered trees, found in regions with seasonal rainfall. The major benefits of savanna vegetation are: 1. Livestock farming: Savanna vegetation provides a natural habitat for many grazing animals, such as zebras, giraffes, and antelopes, which are an important source of meat and dairy products for humans. 2. Arable crop cultivation: Savanna soils are generally fertile and can be used for crop cultivation, particularly in areas where rainfall is sufficient for agriculture. 3. Game reserves: Savanna vegetation is a popular tourist attraction, and many savanna areas have been set aside as game reserves or national parks to protect the wildlife and provide recreational opportunities. 4. Biodiversity: Savanna vegetation supports a high level of biodiversity, with many species of plants and animals adapted to the unique climate and soil conditions of the region. On the other hand, "aqua culture" refers to the cultivation of aquatic organisms, such as fish and shellfish, in controlled environments such as ponds, tanks, or ocean pens. This practice is not commonly associated with savanna vegetation, as savannas are generally characterized by dry grasslands with few bodies of water suitable for aquaculture. Therefore, "aqua culture" is not a major benefit of savanna vegetation.

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All the options listed are benefits of irrigation farming except for "making farmers depend solely on rainfall." Irrigation farming involves the controlled application of water to crops to supplement natural rainfall, which allows for more efficient water use and better crop yields. With irrigation, farmers can plant crops all year round, not just during the rainy season, making early planting possible. Additionally, irrigation can lead to bumper harvests, as crops receive adequate water and nutrients. Furthermore, irrigation farming can provide employment opportunities, as additional labor may be required for digging canals, constructing dams, and operating irrigation systems. However, irrigation farming does not make farmers depend solely on rainfall, as the purpose of irrigation is to supplement and enhance rainfall, not replace it.

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(a) Instruments used to measure rainfall

Rainfall is measured with a rain gauge and a graduated measuring cylinder. The rain gauge has a metal outer cylinder sunk firmly in the ground. At its top is a funnel with a receiving rim of known area. The funnel directs rainwater into a glass collecting bottle placed inside the outer cylinder. The collected water is poured into a graduated measuring cylinder and its depth is read in millimetres.

(b) How total annual rainfall is obtained

1. The rain gauge is inspected at the same fixed time every day, commonly 09:00 hours.
2. The funnel is removed and the water in the collecting bottle is poured into the graduated measuring cylinder.
3. The water level is read at eye level from the graduation in millimetres. This gives the daily rainfall.
4. The daily rainfall readings are added to obtain each month's total rainfall.
5. The totals for the twelve months are added to obtain the total annual rainfall:

\[\text{Total annual rainfall} = \sum_{m=1}^{12}\text{monthly rainfall total}\]

(c) Precautions

1. The rain gauge should be sited in an open space, well away from trees, buildings and walls that may intercept rain or cause dripping.
2. It should be fixed firmly with the rim level and about 25 to 30 cm above the ground, to prevent splashing into the gauge.
3. Readings should be taken daily at the same time, and the collecting bottle should be emptied after each reading.

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(a) Outline map of Africa

Key: dark green represents the Equatorial rain forest; light yellow represents Tropical grassland (savanna). Kisangani is a town in the equatorial rain-forest belt, while Kano is a town in the tropical grassland belt.

(b) Characteristics of the Equatorial rainforest vegetation

1. It has a distinct layered or storeyed structure: very tall emergent trees rise above a nearly continuous canopy, with smaller trees, shrubs and herbs below.
2. The trees are tall, broad-leaved and evergreen. They shed their leaves at different times of the year, so the forest remains green throughout the year.
3. The vegetation is very dense and contains many mixed species rather than pure stands. Trees commonly have long straight trunks and large buttress roots; lianas and epiphytes are also abundant.

(c) Economic importance of tropical rainforest vegetation

1. It provides valuable hardwood timber, such as mahogany, iroko and obeche, for building, furniture, plywood and railway sleepers. Timber exports earn foreign exchange.
2. It supplies forest products and industrial raw materials, including medicinal leaves, roots and bark, rubber, cane or rattan, fruits, seeds, dyes and tanning materials.
3. It provides employment and income through lumbering, sawmilling, furniture making, hunting, collection of forest products and forest administration. Government also earns revenue from licences and timber royalties.

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(a) Sketch map of Africa

Key: ● Oil-producing area and town marked on the sketch map.

(b) Contributions of petroleum to the economic development of the Niger Delta/Nigeria

1. Foreign-exchange earnings: Export of crude petroleum earns Nigeria substantial foreign exchange for importing machinery, medicines and other goods.
2. Government revenue and employment: Royalties, taxes and export proceeds provide revenue for government, while oil companies, refineries and related services create jobs and incomes.
3. Development of industries and infrastructure: Petroleum has encouraged refineries, petrochemical and other ancillary industries, as well as the development of roads, ports, pipelines, power supply, schools and hospitals.

(c) Problems affecting petroleum mining in the Niger Delta

1. Difficult terrain: Mangrove swamps, creeks, waterlogged land and offshore sites make prospecting, drilling, transport and laying pipelines difficult and expensive.
2. Oil spills and environmental pollution: Pipeline leaks and blow-outs pollute rivers, farmland and fishing grounds, destroy aquatic life and cause conflicts with local communities.
3. High cost and insecurity: Exploration and production require huge capital, modern equipment and skilled personnel. Pipeline vandalism, sabotage, theft and insecurity can interrupt production and raise operating costs.

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(a) Definition of soil

Soil is the thin, loose upper layer of the earth's surface made up of weathered rock particles (mineral matter), organic matter (humus), water, air and living organisms, in which plants grow.

(b) Three functions of soil

• It anchors plant roots and holds plants firmly in place.
• It supplies plants with water, air and mineral nutrients.
• It provides a habitat for micro-organisms and small animals that recycle nutrients.
• It serves as a medium for farming and a base for building.

(c) Two negative effects of man's activities on soil

• Soil erosion: deforestation, overgrazing and bad farming expose the soil so that water and wind wash or blow away the fertile topsoil.
• Loss of fertility/degradation: continuous cropping without rest, and burning, exhaust the nutrients and destroy the soil structure.
• Pollution of soil by chemicals, refuse and oil spillage.

(d) Two methods of conserving soil

• Contour ploughing/terracing: ploughing across the slope and building terraces to slow run-off and check erosion.
• Crop rotation and fallowing: alternating crops and resting the land, plus adding manure/fertiliser, to restore fertility.
• Afforestation and cover cropping to bind and shade the soil, and mulching to protect the surface.

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(a) Comparative (group) bar graph

Use the vertical scale: 1 major division = 100,000 kg. The bars for each state are grouped together, with the key showing the years.

Title: Quantity of Yams Produced by States A, B, C and D, 2003–2006.
Horizontal axis: States.
Vertical axis: Quantity of yams produced (kg).

(b) Advantages of comparative bar graphs

1. They make comparison of quantities for different items or years easy.
2. They give a vivid and clear impression of the quantities involved.

(c) One other method is a divided bar graph, also called a composite bar graph.

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(a) What is water pollution?

Water pollution is the contamination of water bodies (rivers, lakes, seas and underground water) with harmful substances that make the water dirty, unsafe and unfit for drinking, farming, aquatic life or other uses.

(b) Three causes of water pollution

• Discharge of untreated sewage and domestic waste into water bodies.
• Release of industrial effluents and chemicals from factories.
• Oil spillage from tankers, pipelines and oil fields.
• Run-off of agricultural fertilisers and pesticides, and dumping of refuse in water.

(c) Three effects of water pollution

• It causes water-borne diseases such as cholera, typhoid and dysentery in humans.
• It kills fish and other aquatic organisms, reducing the fishing industry.
• It makes water unfit for drinking, irrigation and domestic use, raising the cost of water treatment.
• It damages the ecosystem and can cause loss of biodiversity.

(d) Two control measures

• Treat sewage and industrial effluent before it is released into water bodies.
• Enforce anti-pollution laws and penalise offenders.
• Prevent and quickly clean up oil spills, and provide proper waste-disposal systems, plus public enlightenment.

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(a) Rural settlement explained

A rural settlement is a group of dwellings in the countryside where the population is small, sparsely spread and mainly engaged in primary activities such as farming, fishing, herding or lumbering, with few social amenities.

(b) Three types of rural settlement

• Nucleated (clustered) settlement: houses are grouped closely together around a central point such as a market, well or road junction.
• Dispersed (scattered) settlement: houses are spread far apart, each usually standing on its own farmland.
• Linear (ribbon) settlement: houses are strung out in a line along a road, river or valley.

(c) Five differences between rural and urban settlements

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(a)(i) Three commodities of world trade

• Crude petroleum (oil).
• Machinery and manufactured goods (vehicles, electronics).
• Agricultural products such as cocoa, coffee, wheat.

(a)(ii) Three sea routes in the world

• The North Atlantic route (between Western Europe and North America).
• The Suez Canal route (linking Europe with Asia via the Mediterranean and Red Sea).
• The Panama Canal route (linking the Atlantic and Pacific Oceans). (Also the Cape of Good Hope route.)

(b) Four conditions that promote trade among countries

• Differences in natural resources: countries exchange what they have in surplus for what they lack.
• Differences in climate and relief: allow production of different goods that can be exchanged.
• Differences in level of technology: industrial nations trade manufactured goods for raw materials.
• Good transport and communication: efficient shipping and ports ease the movement of goods.
• Peace, stable currencies and trade agreements between nations.

(c) Three reasons for the low volume of trade among African countries

• African countries produce similar raw materials, so they have little to exchange among themselves.
• Poor transport and communication links between the countries.
• Different currencies, languages and colonial ties that direct trade towards Europe rather than within Africa.
• Low level of industrialisation, so few manufactured goods are available to trade locally.

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(a) Four irrigation areas in the Nile Valley

• The Nile Delta (Lower Egypt, around Cairo/Damietta/Rosetta branches).
• The Faiyum (Fayoum) Depression.
• The Gezira Scheme in the Sudan (between the Blue and White Nile).
• Upper Egypt around Aswan and the area behind the Aswan High Dam (Lake Nasser).

(Other acceptable areas: the Middle Egypt reaches around Asyut; the New Halfa scheme.)

(b) The perennial method of irrigation in the Nile Valley

Perennial (all-year) irrigation is the modern system in which water is stored and supplied to the land throughout the year, so that two or three crops can be grown annually instead of one.

• Large dams and barrages (for example the Aswan High Dam) are built across the Nile to hold back the flood water in a reservoir such as Lake Nasser.
• The stored water is released steadily and led away by a network of main and branch canals which distribute it to the fields all through the year.
• Water is lifted to the fields where necessary by devices such as the shaduf, sakia (water-wheel) and Archimedean screw, or by mechanical pumps.
• Because water is available at all seasons, the farmer no longer depends on the natural annual flood, and the land is cropped continuously.

(c) Four problems created by irrigation in the Nile Valley

• Salinity (salinisation): constant watering without natural flushing leaves salts in the soil as the water evaporates, reducing fertility.
• Waterlogging and rising water table: excessive irrigation raises the water table and floods the root zone, harming crops.
• Loss of natural silt/fertility: the dam traps the fertile silt behind it, so farmers must now buy expensive artificial fertilisers to replace it.
• Spread of water-borne diseases: permanent standing water in canals encourages bilharzia (schistosomiasis) and malaria, and also allows aquatic weeds to choke the canals.

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(a) Sketch map of Nigeria

Key: The shaded south-western belt represents the cocoa belt. The hatched northern belt represents the groundnut belt. Kano is shown as a town in the groundnut belt.

(b) Physical conditions required for groundnut production in Nigeria

1. Moderate rainfall: annual rainfall of about 500 to 1,000 mm, sufficient for growth but not excessive.
2. A long dry, sunny season: this permits ripening, harvesting, drying and safe storage of the nuts.
3. Loose, well-drained sandy or loamy soil: this allows the pegs and pods to develop easily in the soil and prevents waterlogging.

Other acceptable conditions include wide level plains for mechanised cultivation and temperatures of about 25°C to 30°C.

(c) Contributions of groundnut production to the economy of Nigeria

1. It provides employment and income for farmers, traders, transporters and processors.
2. It earns foreign exchange through the export of groundnuts, groundnut oil and cake.
3. It supplies raw materials to industries producing vegetable oil, margarine, soap and groundnut cake.
4. It provides food for people and cake for livestock feed.
5. It has encouraged the development of roads, railways, markets and towns, especially in northern Nigeria.

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Explanatory notes on drought

Drought is a long period of abnormally low or no rainfall which causes a serious shortage of water for people, plants and animals.

(a) Causes

• Prolonged failure or lateness of the rains and general low, unreliable rainfall.
• Deforestation and removal of vegetation, which reduce local moisture and rainfall.
• Southward advance of dry desert conditions (desertification) and dry, dust-laden winds such as the harmattan.
• Climatic change and shifting of the rain-belts, and over-grazing/over-cultivation that dry out the land.

(b) Effects

• Crop failure, famine and food shortage.
• Death of livestock and wild animals from lack of water and pasture.
• Drying up of rivers, wells and reservoirs, causing acute water shortage.
• Migration of people and animals, and outbreaks of disease and poverty.

(c) Control

• Afforestation and reforestation to check desert advance and improve local rainfall.
• Building of dams, boreholes and irrigation schemes to store and provide water.
• Practising good land management (avoiding over-grazing and over-cultivation) and planting drought-resistant crops.
• Providing relief materials and early-warning weather forecasting to affected people.

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(a) Three features of local craft industry in Nigeria

• It uses simple, locally-made tools and local raw materials (clay, leather, cotton, wood, metal).
• It is small-scale, run by individuals or families using manual skill and little capital.
• The skills are traditional, often passed down within families, and the products (pots, cloth, mats, carvings) serve mainly the local market.

(b) Four factors affecting the location of manufacturing industries in Nigeria

• Availability of raw materials: industries locate near their raw materials, especially if bulky or perishable.
• Nearness to market: firms making consumer goods settle near the large centres of demand.
• Availability of power/energy: industries need reliable electricity or fuel.
• Transport facilities: good roads, rail and ports for moving materials and goods.
• Supply of labour and capital, and availability of water.

(c) Three ways industries have contributed to Nigeria's economy

• They provide employment and income for many people.
• They add value to local raw materials and reduce dependence on imported goods.
• They earn foreign exchange through the export of manufactured goods and generate revenue/taxes for government.
• They encourage the growth of towns and the development of infrastructure.

Detalles de la respuesta

(a) What is a plateau?

A plateau is an extensive area of highland with a fairly level or gently undulating top and steep sides, standing well above the surrounding land. It is often called a tableland.

(b) Two types of plateaux

• Volcanic (lava) plateau.
• Dissected/tectonic (block) plateau. (Others: intermont plateau, continental plateau.)

(c) Formation of one type of plateau

Volcanic (lava) plateau: During quiet, fissure eruptions, very fluid basaltic lava wells up through long cracks in the earth's crust and spreads out over a wide area. As successive flows cool and solidify one on top of another, they build up thick, horizontal sheets of rock with a broad, flat surface. Over time this piled-up lava forms an extensive, level upland known as a lava or volcanic plateau (for example the Jos Plateau region and the Deccan of India).

(d) Three ways plateaux are important to man

• They are rich in minerals (tin, gold, coal), which are mined.
• Their cool climate favours settlement, health resorts and the growing of temperate crops.
• Their edges have waterfalls and rivers that are used to generate hydro-electric power.
• They provide grazing land for livestock and attract tourists with their scenery.

Detalles de la respuesta

(a)(i) What is internal trade?

Internal trade (domestic or home trade) is the buying and selling of goods and services within the boundaries of a single country, using the country's own currency and moving goods from areas of surplus to areas of demand.

(a)(ii) Four commodities involved in internal trade in Nigeria

• Foodstuffs such as yam, rice, beans and garri.
• Livestock and animal products such as cattle, goats and hides.
• Manufactured/consumer goods such as textiles, soap and cement.
• Cash and forest products such as kola nut, palm oil, timber and vegetables.

(b) Four factors that encourage internal trade in Nigeria

• Regional differences in resources and production: the north produces grains and livestock while the south produces roots, palm produce and manufactures, encouraging exchange between zones.
• Improved transport network: roads, railways and waterways link producing and consuming areas, allowing goods to move cheaply.
• Large population and market: a big and growing population creates high demand for goods and services.
• Common currency and language of trade, and a single political unit: the naira and shared trading languages (Hausa, Yoruba, Igbo, English) ease transactions and remove internal tariff barriers.

Other valid points: presence of markets and middlemen, banking and credit facilities, division of labour/specialisation.

(c) Three problems limiting internal trade in Nigeria

• Poor transport and infrastructure: bad roads, few railways and poor storage raise costs and cause spoilage of perishable goods.
• Inadequate capital and credit facilities: many traders operate on a small scale and cannot expand.
• Insecurity and multiple taxation/levies: armed robbery, unrest and illegal tolls on highways discourage the movement of goods.

Other valid points: seasonal fluctuation and price instability, lack of market information, poor storage/preservation.

Detalles de la respuesta

(a) Formation of clouds

Clouds are masses of tiny water droplets or ice crystals floating in the sky. They form when warm, moist air rises and cools. As the air rises it expands and its temperature falls; when it cools to the dew point the water vapour it carries can no longer stay as a gas, so it condenses around tiny dust particles (condensation nuclei) in the atmosphere. Countless tiny droplets so formed collect together to become a visible cloud. The air may be forced to rise by heating of the ground (convection), by being pushed over mountains (relief), or where warm and cold air meet (frontal uplift).

(b) Relief (orographic) rainfall

Relief rainfall forms when moist air from the sea is forced to rise over a highland or mountain barrier. As the air climbs the windward slope it cools, its vapour condenses into cloud and heavy rain falls on that side of the mountain. Having lost most of its moisture, the air descends the far (leeward) slope, where it warms and dries; this drier side receives little rain and is called the rain shadow. Relief rainfall therefore gives heavy rain on the windward slope and a dry rain shadow on the leeward slope.

Detalles de la respuesta

(a) Distance from Agbeyangi to Marafa "as the crow flies"

Join the two places with a straight line and measure it on the map. The straight-line distance measures 20.6 cm. On a scale of 1:50,000, 1 cm represents 50,000 cm on the ground, so

\[ \text{Actual distance} = \frac{20.6 \times 50{,}000}{100{,}000}\ \text{km} = 10.3\ \text{km}. \]

The distance from Agbeyangi to Marafa is 10.3 km.

(b) Drainage of the mapped area

• The area is well drained, being covered by a network of well-defined stream channels.
• The major river is the River Oshin, which flows in a north-easterly direction and has many tributaries.
• The general drainage pattern is dendritic.
• The central ridge is the main watershed from which many rivers take their source.
• The rivers are at an early (youthful) stage of development, shown by the V-shaped valleys and the dissected highlands produced by active downward cutting.
• The smaller ridge at the north-eastern corner has rivers radiating from it, while the rivers in the north-west flow northwards.

(c) Relationship between the relief and the road network

• The main road takes advantage of the lowland and runs between the two major ridges, avoiding the highland.
• The road keeps to the valley floors, running parallel to Igporin hill rather than climbing it.
• The secondary roads, minor roads and footpaths are built along the spurs.
• The roads avoid steep slopes and pass through gaps such as passes, cols and saddles where the gradient is gentle.

(d) Two land-use types

1. Agricultural land use, shown by areas of scattered cultivation.
2. Transportational land use, shown by the roads, paths and tracks (educational land use is also evident from the schools).

Detalles de la respuesta

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

Key: Coal: Enugu; Limestone: Ewekoro; Crude oil: Niger Delta; Tin: Jos Plateau. Enugu is an important town in the coal-mining area.

(b) Problems associated with mineral exploration in Nigeria

1. Inadequate capital, modern equipment and skilled labour: Exploration, drilling and processing require costly machinery and technical expertise. Shortage of funds, spare parts and trained personnel limits effective exploitation.
2. Difficult terrain and poor transport network: Mineral deposits may occur in swampy Niger Delta creeks, offshore areas or rugged plateau and rocky areas. Poor roads and transport facilities make movement of equipment and minerals difficult and expensive.
3. Environmental and security problems: Oil spillage, gas flaring, land degradation and loss of farmland often cause conflict between host communities and mining companies. Oil theft, pipeline vandalism, sabotage and communal disputes also disrupt operations.

(c) Contributions of minerals to the economic development of Nigeria

1. Foreign exchange and government revenue: Crude oil and other mineral exports earn foreign exchange, while royalties, taxes and rents paid by mining companies increase government revenue.
2. Employment and income generation: Mining, processing, transportation and marketing of minerals provide direct and indirect employment and raise the incomes of workers and miners.
3. Industrial and infrastructural development: Minerals provide raw materials for industries, for example limestone for cement and crude oil for petrochemicals. Mining also encourages the growth of roads, railways, power facilities and mining towns such as Enugu, Jos and Port Harcourt.