WAEC SSCE - Geography - 2007

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A levee is a feature of river deposition. When a river floods, it carries sediment with it and deposits it on the surrounding floodplain. Over time, this sediment builds up and forms a raised bank or ridge called a levee. The size and height of the levee depend on the amount and type of sediment deposited by the river. Levees can help to contain future floods by restricting the river's flow and preventing it from spilling over onto the surrounding land.

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Africa's exploitation of solar energy will not result in less amount of solar energy received by plants for photosynthesis. This is because solar energy is harnessed by installing solar panels or solar collectors which do not reduce the amount of solar energy reaching plants. The other options are all potential benefits of exploiting solar energy in Africa. It can result in savings in liquid fuel and electricity costs as solar energy can be used as an alternative to traditional energy sources. Additionally, it can reduce the use of fuel wood, which can help to prevent deforestation and environmental degradation.

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A landlocked country is a country that is completely surrounded by land and has no direct access to the sea or ocean. China and South Africa are not landlocked countries as they have coastlines along the sea. Tunisia is not a landlocked country as it has a coastline along the Mediterranean Sea. Therefore, the answer is Burundi, which is a landlocked country located in East Africa. It is surrounded by Tanzania to the east and south, the Democratic Republic of the Congo to the west, and Rwanda to the north. Being landlocked can have economic implications for a country as it can limit trade and access to international markets.

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Zambia is a major producer of copper. Copper is a valuable metal used in many industries, including construction, electronics, and transportation. Zambia is one of the largest producers of copper in the world, accounting for a significant portion of global production. The country's copper production is primarily located in the Copperbelt region, which is home to some of the world's largest copper mines. The mining industry is a key contributor to Zambia's economy, with copper exports being a significant source of foreign exchange earnings. In contrast, Chad, Burundi, and Morocco are not major producers of copper. While these countries may have some copper deposits, their production levels are relatively small compared to that of Zambia. Therefore, the correct option is "Zambia."

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The rocks at the core of the Earth are believed to be rich in iron and nickel. This is because scientists have studied the behavior of seismic waves passing through the Earth and have observed that they change their speed and direction when they encounter different materials. By analyzing these changes, scientists have determined that the Earth has a solid inner core and a liquid outer core. The outer core is thought to be composed of a mixture of molten iron and nickel, while the inner core is thought to be a solid ball of iron and nickel. This is supported by the fact that meteorites, which are believed to be remnants from the early solar system, also contain high amounts of iron and nickel.

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The instrument used for measuring atmospheric pressure is a barometer. A barometer is an instrument that measures atmospheric pressure, which is the force exerted by the weight of the atmosphere on the Earth's surface. The most common type of barometer is the mercury barometer, which consists of a glass tube that is closed at one end and filled with mercury. The tube is then turned upside down and inserted into a container of mercury, which allows the mercury in the tube to settle at a certain height. The height of the mercury in the tube is directly proportional to the atmospheric pressure, with higher pressure pushing the mercury up the tube and lower pressure allowing the mercury to fall. The atmospheric pressure can be read by measuring the height of the mercury column in the tube against a scale. Other types of barometers include aneroid barometers, which use a flexible metal chamber to measure changes in atmospheric pressure, and digital barometers, which use electronic sensors to measure pressure changes. In summary, a barometer is the instrument used for measuring atmospheric pressure. The most common type is the mercury barometer, which measures the height of a column of mercury in a tube to determine the atmospheric pressure.

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The instrument used for measuring relative humidity is called a hygrometer. A hygrometer is a device that measures the amount of moisture or water vapor in the air. It is an important instrument used in meteorology to help understand and predict weather patterns. The two common types of hygrometers are the mechanical and electronic hygrometers. The mechanical hygrometer uses a human hair or a piece of organic material that changes length in response to humidity changes. The electronic hygrometer, on the other hand, uses sensors to measure humidity levels and displays the readings on a screen.

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The area around the Equator is known as the Intertropical Convergence Zone (ITCZ) which is a belt of low pressure. The ITCZ is sometimes referred to as the doldrums because it is typically characterized by calm winds and sudden thunderstorms. The air in this area is heated by the sun, which causes it to rise and create a region of low pressure. As the air rises, it cools and the moisture in it condenses, leading to the formation of clouds and precipitation. This region is also characterized by high humidity due to the large amounts of moisture in the air. Therefore, the correct answer is the "doldrums", which is the area of low pressure around the Equator. It is an important area for shipping and navigation, as well as for the climate of the surrounding regions.

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The dominant climatic elements that control soil development are temperature and precipitation. Temperature affects the rate of chemical reactions that break down rocks and minerals, which form the basis of soil. High temperatures speed up these reactions, while low temperatures slow them down. Precipitation, on the other hand, affects the amount of water available to weather rocks and minerals, and to transport the resulting soil particles. It also affects the leaching of nutrients from the soil. In areas with high precipitation, there may be more leaching of nutrients from the soil, leading to nutrient-poor soils. Together, temperature and precipitation determine the rate of weathering, erosion, and soil formation. In areas with high temperatures and low precipitation, soil development may be slow due to limited water availability. Conversely, in areas with high precipitation and moderate temperatures, soil development may be rapid, but the soil may be nutrient-poor due to leaching. In summary, temperature and precipitation are the two dominant climatic elements that control soil development, with temperature affecting the rate of chemical reactions and precipitation affecting water availability and nutrient leaching.

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Loess is not a metamorphic rock. Metamorphic rocks are formed from the transformation of existing rocks through heat, pressure, and chemical processes. Slate, marble, and gneiss are all examples of metamorphic rocks. Slate is formed from the metamorphism of shale or mudstone, marble from the metamorphism of limestone, and gneiss from the metamorphism of other rocks such as granite or schist. In contrast, loess is a type of sediment that is made up of fine-grained, windblown particles such as silt, sand, and clay. It is deposited in areas such as floodplains and desert basins and can be several meters thick. In summary, loess is not a metamorphic rock, while slate, marble, and gneiss are all examples of metamorphic rocks. Loess is a type of sediment that is deposited in areas such as floodplains and desert basins.

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The Andes is not a mountain in Africa. The Atlas Mountains are located in North Africa, primarily in Morocco, Algeria, and Tunisia. The Tibesti Mountains are in the Sahara Desert and are located in the northern part of Chad and the southern part of Libya. The Rwenzori Mountains, also known as the "Mountains of the Moon," are located in the border region between Uganda and the Democratic Republic of the Congo. In contrast, the Andes is a mountain range located in South America, extending through seven countries from Venezuela in the north to Argentina and Chile in the south. In summary, the Andes is not a mountain in Africa. The Atlas Mountains, Tibesti Mountains, and Rwenzori Mountains are all located in Africa, while the Andes is a mountain range located in South America.

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The distance between Accra, latitude 5030N and latitude 51030N can be calculated using the formula: distance = 111.12 x difference in latitude. So, the difference in latitude is 51°30'N - 5°30'N = 46°. Substituting this value into the formula gives: distance = 111.12 x 46 = 5,107.52 km. Rounding up to the nearest whole number gives a distance of 5,108 km. Therefore, the answer is option D: 5,106 km.

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The Sahel savanna vegetation is predominantly found in Mauritania. The Sahel is a transitional zone between the Sahara desert to the north and the Sudanian savanna to the south. Mauritania is located in the western part of the Sahel region and has a semi-arid climate, which is characterized by low and erratic rainfall. The vegetation in this region is adapted to these conditions, with grasses and shrubs being the dominant plant types.

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The correct answer is option A: I and III only. Rift valleys are formed due to tensional forces in the Earth's crust which pull the crust apart, causing it to stretch and thin. This leads to the formation of a depression or a valley, which is further deepened by erosion and other geological processes. Lateral forces and compressional forces, on the other hand, result in the formation of folds, mountains, and other geological features. The subsidence of the rift valley floor occurs after the valley has been formed, as a result of the continued movement of the Earth's crust.

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The correct answer is "tilting of the earth on its axis." The tilt of the earth's axis does not necessarily prove that the earth is spherical in shape, as a similar tilt could also occur in a non-spherical shape. The other options listed provide evidence that the earth is spherical in shape: - The curved horizon of the earth: when looking at the horizon from a high altitude, such as from an airplane or a mountain, the curvature of the earth can be seen. This is because the surface of the earth curves away from the observer's line of sight. - The eclipse of the moon: during a lunar eclipse, the earth passes between the sun and the moon, casting a shadow on the moon's surface. The curved shape of the earth's shadow on the moon provides evidence of the earth's spherical shape. - Aerial photograph of the earth taken by astronauts: photographs taken from space show the earth as a spherical shape, as the entire surface of the earth can be seen from this vantage point.

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The relationship between the elements of an ecosystem is best described as interdependent. This means that the different living and non-living components of an ecosystem rely on each other to survive and thrive. For example, plants produce oxygen through photosynthesis, which is essential for the survival of animals that breathe oxygen. Similarly, animals provide nutrients for plants through their waste, which helps the plants grow. In this way, the different elements of an ecosystem are interconnected and rely on each other in a complex web of relationships.

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The characteristic of warm currents that is not mentioned in the options is that they flow from the polar regions to the equatorial region. Warm currents flow from the equatorial region towards the poles, carrying warm water from the tropics towards higher latitudes. This results in a warming effect on the regions they flow through, affecting both the climate and the oceanic ecosystem. Warm currents are also characterized by high surface temperatures due to the warm water they transport, and they tend to flow along the east coast of continents.

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The answer is "inadequate workforce" because overpopulation usually results in an excess of labor supply, which can lead to unemployment, but not inadequate workforce. Inadequate workforce implies a shortage of people available to work, which is not a typical result of overpopulation. Overpopulation can lead to a rapid increase in population, which can cause various problems, such as the strain on resources, the decline in the standard of living, and the decline in the standard of health due to a lack of access to essential resources and services. Therefore, inadequate workforce is not a problem of overpopulation.

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Equal degree of cloudiness is represented by an isoneph chart. An isoneph chart is a map that shows areas of equal cloudiness. The term "isoneph" comes from the Greek words "isos," meaning equal, and "nephe," meaning cloud. On an isoneph chart, lines are drawn to connect points that have the same amount of cloud cover. For example, on an isoneph chart, areas with 50% cloud cover will be connected by a line, and areas with 70% cloud cover will be connected by another line. The lines allow meteorologists to easily identify areas of similar cloud cover, which can be helpful in predicting weather patterns. In summary, equal degree of cloudiness is represented by an isoneph chart, which is a map that shows areas of equal cloud cover by connecting points with the same amount of cloud cover with lines.

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Seasonal changes in weather and climate are primarily caused by the revolution of the Earth around the Sun. The Earth takes approximately 365.25 days to complete one orbit around the Sun, which is known as a year. As the Earth orbits the Sun, it is tilted at an angle of approximately 23.5 degrees relative to the plane of its orbit. This means that different parts of the Earth receive different amounts of sunlight at different times of the year. When a particular hemisphere of the Earth is tilted towards the Sun, it receives more direct sunlight and experiences warmer temperatures. This is the season of summer in that hemisphere. Conversely, when that hemisphere is tilted away from the Sun, it receives less direct sunlight and experiences cooler temperatures. This is the season of winter in that hemisphere. The other two options listed, rotation of the Earth on its axis and the direct overhead sun on the Tropic of Cancer or Capricorn, do not directly cause seasonal changes. The rotation of the Earth on its axis causes the alternation of day and night, while the direct overhead sun on the Tropic of Cancer and Capricorn marks the solstices, which are the longest and shortest days of the year, respectively. However, these events do not directly cause changes in the seasons.

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Convectional rains are most common in equatorial regions and tropical monsoon climates. Convectional rainfall occurs when the sun heats the ground, causing air to rise and cool. As the air rises, it cools and condenses, forming clouds. Eventually, the clouds become so full of moisture that they release rain. Equatorial regions and tropical monsoon climates are characterized by high temperatures and humidity, which create ideal conditions for convectional rainfall. The warm, moist air rises quickly, forming cumulus clouds that can develop into thunderstorms. These regions also experience a lot of sunshine, which helps to heat the ground and create the conditions for convectional rainfall. In contrast, polar regions and Mediterranean climates are not as conducive to convectional rainfall because they are generally cooler and drier. Temperate regions may experience convectional rainfall in the summer months when temperatures are warmer, but it is not as common as in equatorial regions and tropical monsoon climates. In summary, convectional rains are most common in equatorial regions and tropical monsoon climates because these regions have high temperatures, humidity, and abundant sunshine, which create the ideal conditions for convectional rainfall to occur.

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Humidity refers to the amount of water vapour in the air. When water evaporates from bodies of water or moist surfaces, it turns into water vapour and mixes with the air. The amount of water vapour that air can hold depends on its temperature and pressure. Warm air can hold more water vapour than cold air. When the air is saturated with water vapour, any additional water vapour will condense into tiny water droplets and form clouds, mist or fog. So, humidity is not the same as cloud cover or mist, but rather the amount of water vapour present in the air.

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Density maps are most appropriate for showing the distribution of people in a place. A density map represents the density of a certain phenomenon, in this case, people, in a given area or region. The map shows the concentration of people in specific regions or areas, highlighting areas with high or low population density. Density maps are useful in understanding population distribution patterns and can help in analyzing trends, identifying areas of growth or decline, and making informed decisions related to urban planning, resource allocation, and social and economic development.

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During the equinoxes, day and night are equal in length for all places throughout the world. The equinox is a time when the sun is directly above the equator, and as a result, the length of day and night is roughly equal at all points on the Earth's surface. This occurs twice a year, around March 20-21 and September 22-23. Therefore, is the correct answer.

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The intrusive rocks are formed from the cooling and solidification of magma beneath the Earth's surface, whereas extrusive rocks are formed from the cooling and solidification of lava on the Earth's surface. Out of the given options, granite is an intrusive rock. Granite is a coarse-grained, igneous rock that is composed primarily of minerals like quartz, feldspar, and mica. It is formed by the slow cooling and solidification of magma deep beneath the Earth's surface, giving it a coarse texture and distinct mineral grains that are visible to the naked eye. In contrast, shale, sandstone, and marble are all sedimentary rocks that are formed from the accumulation and compaction of sediment or the recrystallization of existing rocks. Shale is formed from the accumulation of clay and silt-sized particles, sandstone from sand-sized particles, and marble from the recrystallization of limestone or dolomite. In summary, granite is the intrusive rock out of the given options. It is formed from the cooling and solidification of magma deep beneath the Earth's surface, giving it a coarse texture and distinct mineral grains. The other options are all sedimentary rocks that are formed from the accumulation and compaction of sediment or the recrystallization of existing rocks.

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A fog is most likely to develop when a warm moist wind blows over a cold current. Fog is a type of low-lying cloud that forms when the air near the ground cools and reaches its dew point, causing water vapor to condense into tiny water droplets. In order for fog to form, there needs to be moisture in the air and a cooling mechanism. When a warm moist wind blows over a cold current, the warm air is cooled by the cold water below. This cooling process can cause the air to reach its dew point and form fog. This type of fog is called advection fog and is commonly seen near coastal areas where warm ocean currents flow over cold water. In contrast, when a cold dry wind blows over a cold current, there is little moisture in the air to form fog. Similarly, when a cold dry wind blows over a warm current or a warm moist wind blows over a warm current, the air is not cooled enough to reach its dew point and form fog. In summary, a fog is most likely to develop when a warm moist wind blows over a cold current because the warm air is cooled by the cold water below, causing the air to reach its dew point and form fog.

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Chemical weathering is a process by which rocks are broken down and transformed into new substances through chemical reactions. This process is most effective in hot and wet environments. In hot and wet environments, chemical weathering is facilitated by the high temperatures and the presence of water. The heat provides energy for chemical reactions to occur, while water acts as a solvent, carrying and reacting with minerals within rocks. This process can lead to the breakdown of minerals, the release of nutrients, and the formation of new minerals that are more stable in the environment. In contrast, cold and dry environments do not provide enough energy for chemical reactions to occur quickly, and water is often limited, which can slow down the process of chemical weathering. Similarly, while warm and dry environments can provide energy for chemical reactions, the lack of water can limit the effectiveness of the process. Therefore, the most effective environment for chemical weathering is hot and wet, as it provides both the necessary energy and water to facilitate the breakdown and transformation of rocks through chemical reactions.

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Nairobi is not a capital city of an ECOWAS state. Nairobi is the capital city of Kenya, which is not a member state of ECOWAS. ECOWAS stands for Economic Community of West African States, and its member states are located in West Africa. The other options given in the question - Lome, Dakar, and Bissau - are all capital cities of ECOWAS member states, which are Togo, Senegal, and Guinea-Bissau, respectively.

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The largest off-shore island in Africa is the island of Madagascar. It is located off the east coast of Africa in the Indian Ocean and is the fourth largest island in the world. The island is home to a diverse range of plants and animals, many of which are found nowhere else in the world. Madagascar has a rich cultural heritage, with a mix of African, Asian and European influences. The island is known for its unique wildlife, stunning landscapes, and beautiful beaches, making it a popular tourist destination.

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The correct answer is option D: "on-shore movement of cold air". This is because cold air is denser than warm air, and as such, it tends to move towards areas of lower pressure. In Africa, the areas of low pressure are typically associated with the Inter-Tropical Convergence Zone (ITCZ), which is a belt of low pressure that circles the Earth near the Equator. The movement of the ITCZ, the convectional nature of hot tropical air, and the movement of moist air masses over higher ground are all factors that contribute to rainfall in Africa. However, the on-shore movement of cold air is not a significant factor in rainfall patterns in Africa.

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The movement of the Earth around the Sun is known as revolution. The Earth takes approximately 365.25 days to complete one orbit or revolution around the Sun. This movement is responsible for the change in seasons and the different amounts of daylight and darkness throughout the year. It is important to note that revolution is different from rotation. Rotation refers to the Earth's spinning on its axis, which takes approximately 24 hours to complete one rotation. Rotation is responsible for the alternation of day and night. Orbit is another term used to describe the Earth's movement around the Sun, but it is not as commonly used as revolution. Evolution, on the other hand, is a term used to describe the gradual development or change of something over time, and is not related to the movement of the Earth around the Sun.

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The largest man-made lake in Africa is Lake Volta. Lake Volta is located in Ghana, West Africa, and was created by the construction of the Akosombo Dam on the Volta River. The lake covers an area of approximately 8,502 square kilometers (3,283 square miles) and has a maximum depth of 140 meters (460 feet). It is one of the largest reservoirs in the world by surface area and the largest man-made lake in Africa. The construction of the Akosombo Dam and the creation of Lake Volta had significant impacts on the local environment and communities. The dam provides hydroelectric power to Ghana and neighboring countries, but it also flooded large areas of land, displaced tens of thousands of people, and disrupted ecosystems and fisheries. In summary, Lake Volta is the largest man-made lake in Africa, created by the construction of the Akosombo Dam on the Volta River in Ghana.

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(a) Sketch map of the Nile Valley

Key farming areas and products

1. Nile Delta, Egypt: cotton and rice.
2. Gezira Plain, Sudan: cotton and groundnuts.

(b) Economic importance of the River Nile to Egypt and Sudan

1. It supplies water for irrigation, making farming possible in the dry Nile Valley and Delta.
2. Its annual deposits of fertile alluvial silt enrich the flood plains for crop cultivation.
3. It provides hydro-electric power where dams have been built, for example at the Aswan High Dam in Egypt, and the Sennar and Khashm el-Girba dams in Sudan.
4. It supplies water for domestic uses, industries and livestock.
5. It supports fishing and provides employment and food for the people.
6. It is used for river transport and also attracts tourists, especially along the Nile in Egypt.

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(a) Constructing the flow map / flow chart

A flow map shows movement between places by drawing a band (arrow) along each route whose width is drawn in proportion to the quantity of traffic along that route.

Step 1: Choose a width scale. Let 1 mm of band width = 50,000 passengers. Then divide each value by 50,000 to get the band width:

Step 2: Draw the bands. On the map of Nigeria (Map B) draw a proportional-width band from Lagos to each city, each band ruled to the width above and following the direction of the route. Shade the bands, add arrowheads to show direction of movement, and provide a title and a key showing the width scale (e.g. a 1 mm band = 50,000 passengers).

(b) Two advantages of representing data with flow maps

1. They show clearly the direction and route of movement between places, so the reader sees where the traffic goes as well as how much there is.
2. The proportional band widths give an instant visual comparison of the volume of traffic along the different routes on the actual geographical map.

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(a) Four factors that favour the location of a brewery industry:

• Abundant supply of clean water: brewing uses large volumes of water, so breweries are sited where good quality water is plentiful.
• Nearness to raw materials: ready supply of barley/sorghum, hops, sugar and yeast reduces transport costs.
• Large market/high population: breweries locate near towns and cities where there is a big demand for the drink, since the product is bulky and perishable.
• Availability of power, labour and good transport: a steady energy supply, skilled and unskilled workers, and good roads/rail to distribute the finished product all attract the industry. (Capital and availability of bottles/containers are also acceptable.)

(b) Three contributions of manufacturing industries to economic development of Tropical Africa:

• Employment: they create many jobs, raising incomes and living standards.
• Revenue and foreign exchange: they earn money for government through taxes and provide manufactured goods for export, saving/earning foreign exchange.
• Development and diversification: they add value to local raw materials, encourage the growth of other industries and infrastructure, and reduce dependence on imports.

(c) Three problems facing manufacturing industries in Tropical Africa:

• Shortage of capital and inadequate funding for machinery and expansion.
• Inadequate power supply and poor infrastructure (erratic electricity, poor roads), which raise costs and disrupt production.
• Shortage of skilled labour and low-level technology, together with a small local market and competition from imported goods.

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(a) Outline map of Nigeria showing three vegetation belts and towns

(b) Effects of rainfall on vegetation in Nigeria

1. High and prolonged rainfall in southern Nigeria encourages luxuriant, dense, evergreen tropical rainforest with tall trees.
2. Moderate seasonal rainfall produces savanna vegetation, consisting mainly of tall grasses with scattered deciduous trees.
3. Low and unreliable rainfall in northern Nigeria results in short grasses, thorny shrubs and widely spaced trees; where rainfall is very scanty, scrub vegetation develops.

(c) Uses of vegetation resources in Nigeria

1. Vegetation provides timber, poles and other materials for building and furniture making.
2. It provides food such as fruits, nuts, vegetables and game.
3. Firewood and charcoal are obtained from trees for domestic fuel.
4. Forest products provide raw materials for industries, for example paper, rubber and furniture industries.
5. Leaves, roots and bark are used in preparing traditional medicines.
6. Grasses provide pasture for livestock, while some grasses and leaves are used for thatching roofs.

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

(b) Physical conditions necessary for cocoa production

1. Temperature: Cocoa requires a uniformly high temperature of about 27°C, with a low annual temperature range and no frost.
2. Rainfall: It requires moderate to heavy rainfall of about 125 to 200 cm annually, fairly well distributed through the growing season.
3. Soil and relief: It grows best on deep, fertile, humus-rich and well-drained loamy soil, usually on gently undulating land.
4. Shade and dry period: Young cocoa seedlings need shade. A short dry season, especially from December to February, assists the drying of harvested beans.

(c) Importance of cash crops to the economy of Nigeria

1. Foreign exchange and revenue: Export crops such as cocoa earn foreign exchange for Nigeria and provide revenue to government through taxes and export duties.
2. Employment and income: They provide employment and income for farmers, farm labourers, produce buyers, transporters and traders.
3. Raw materials: They supply raw materials to industries, for example cocoa to beverage and confectionery industries, cotton to textile industries and rubber to tyre industries.
4. Development of settlements: Cash-crop production promotes roads, markets, processing centres and the growth of towns in producing areas.

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(a) Sketch map of Nigeria

Key locations shown on the map:

1. Adamawa Highlands in the North-East.
2. Yoruba Highlands in the West.
3. River Benue, associated with the Adamawa highland region, and River Ogun, rising in the western uplands.
4. Kainji Lake, a man-made lake on the River Niger.
5. Lake Chad in the extreme North-East.

(b) Importance of the highlands of Nigeria

1. They are sources of minerals. The Jos Plateau, for example, has deposits of tin and columbite, while granite and other building stones are obtained from highland areas.
2. They are sources of rivers and water supply. Many rivers rise from highland areas. These rivers provide water for homes, livestock and irrigation and may be used for fishing and other economic activities.
3. They provide sites for hydro-electric power generation. Rivers flowing down steep highland slopes form rapids and waterfalls. These provide suitable conditions for generating hydro-electric power.
4. They attract tourists and support recreation. Their scenic relief, waterfalls, cool climate and natural vegetation make highland areas important tourist centres.
5. They have a cool climate favourable for settlement and specialised farming. Highlands are cooler than surrounding lowlands and support crops such as potatoes, vegetables, tea and apples, especially on the Mambilla Plateau.
6. They provide grazing land for transhumance. During the dry season, pastoralists move cattle to the cooler, better-watered highlands where pasture is available.

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(a) Four differences between Tropical Grassland and Temperate Grassland:

(Also acceptable: savanna supports big game/wildlife, steppe is a major zone for wheat and cattle/sheep ranching.)

(b) Climate of the Tropical Grassland (Savanna):

• High temperatures throughout the year, averaging about \(24^{\circ}\text{C}\), with the hottest period just before the rains.
• Distinct wet and dry seasons: the wet season comes with the overhead sun, the dry season when the sun is overhead in the opposite hemisphere.
• Moderate rainfall, about \(500\text{ to }1000\text{ mm}\) a year, brought by convectional storms in the wet season.
• A relatively small annual temperature range but a marked contrast between the rainy and dry periods; skies are cloudy in the wet season and clear and dusty (harmattan) in the dry season.

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(a) What is a plateau?

A plateau is an extensive area of elevated, fairly level or gently undulating highland that stands above the surrounding land and usually has at least one steep side. It is also called a tableland.

(b) Mode of formation:

(i) Tectonic plateau: Formed by earth movements (crustal forces). A large block of the earth's crust is uplifted more or less evenly by vertical forces, or is left standing between two faults (a raised block), so that a broad surface is raised to a high level without much folding. Some are formed by outpourings of lava (basalt) that build up flat-topped lava plateaux.

(ii) Dissected plateau: Formed when an existing plateau is deeply eroded by rivers and other agents. Streams cut deep valleys and gorges into the raised surface, breaking it into a rugged mass of ridges, hills and valleys. What remains of the original level surface is seen only in the accordant hill tops.

(c) Three ways plateaux are important to man:

• Mining: many plateaux are rich in minerals (e.g. tin and coal on the Jos Plateau), supporting the mining industry.
• Hydro-electric power: rivers descending the plateau edge provide waterfalls and rapids used to generate HEP.
• Settlement, farming and grazing: the cooler, healthier climate of high plateaux favours settlement, arable farming and livestock rearing, and can attract tourism.

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(a) Relief features of the ocean floor

(b) Three characteristics of the continental shelf

1. It is the shallow, gently sloping submerged margin of a continent, extending from the coast to the shelf break.
2. It is generally less than about 200 m deep and is a continuation of the coastal plain beneath the sea.
3. Its width varies considerably, and its shallow water permits sunlight penetration; it is therefore rich in plankton and marine life.

(c) Importance of the continental shelf to man

1. It provides some of the world’s richest fishing grounds because plankton and fish thrive in its shallow, sunlit waters.
2. It contains valuable mineral resources, especially petroleum and natural gas, which are extracted by offshore drilling.
3. Its sheltered shallow waters provide suitable places for anchorage, ports, recreational activities and tourism.

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(a) Marking and naming the features on the map

• Spur (SP): a tongue of high land projecting from a hillside, shown by contours forming a V or U that points DOWN the slope, towards lower values. Mark its nose with the letters SP.
• Gentle slope (GS): an area where the contour lines are widely spaced, showing a small rise over a large horizontal distance. Mark it GS.
• Watershed (WS): the crest of high land separating two drainage basins, so that streams flow away from it in opposite directions. Mark it WS.
• V-shaped valley (VS): a young river valley where the contours form a V pointing UP the slope, with the river at the base of the V. Mark it VS.

(b)(i) Length of River Dakorobi from its source to its confluence with River Sencha

Lay a thread (or the edge of a piece of paper) along the winding river, straighten it against the scale and read the map length.

Length on map = 10.8 cm; Scale = 1:50,000, so 1 cm represents 50,000 cm = 0.5 km.

(b)(ii) Relief of the mapped area

• The area is generally a highland, with heights ranging from about 950 ft to over 3000 ft.
• It is lowest in the north-east and highest in the north-west.
• The north-west is rugged, with steep slopes, V-shaped valleys and cliffs.
• Pockets of isolated hills run from the north-west to the south-east.
• The south-west and north-east have gentle, rolling slopes.

(c) Influence of relief on settlement

• The high relief gives the area a generally dispersed settlement pattern.
• Most settlements are found on the gentle slopes to the south of the map, where building and farming are easier.
• The rugged, mountainous north-west attracts few settlements; the only ones there are Mayo, Dongi and Kenchungu.
• Settlements avoid the steep slopes, while passes attract settlement, for example Karlahi.

Akọwa Nkọwa

(a) Four factors responsible for the sparse population of the West Coast of South Africa:

• Aridity and low rainfall: the west coast (Namib and Karoo margins) is desert to semi-desert, cooled by the cold Benguela current, giving very low, unreliable rainfall that discourages settlement.
• Poor, infertile soils: the dry, sandy and rocky desert soils cannot support arable farming, so few people can make a living from the land.
• Scarcity of surface water: the shortage of rivers and fresh water limits domestic supply, farming and industry.
• Sparse vegetation and limited economic opportunity: the thin scrub vegetation supports little grazing, and the lack of industries and job opportunities gives people little reason to settle. (Rugged, harsh terrain in places is also acceptable.)

(b) Three disadvantages of the low population density:

• Shortage of labour for developing farms, mines and industries.
• Small local market, which discourages investment and the growth of industries and services.
• Under-utilisation of resources and high cost of providing infrastructure (roads, water, electricity) to a scattered population.

(c) Three ways population can be increased:

• Provide water through boreholes, dams and irrigation schemes to support farming and settlement.
• Develop industries and create jobs, and exploit mineral and fishing resources to attract migrants.
• Improve infrastructure and social amenities (roads, housing, schools, hospitals, electricity) to make the area more attractive to settlers.

Akọwa Nkọwa

(a) Characteristics of sedimentary rocks:

• They are formed in layers (strata/beds) which are usually visible as bedding planes.
• They are non-crystalline and generally softer than igneous rocks.
• They frequently contain fossils of plants and animals buried during their formation.
• They are made of compacted and cemented sediments (particles of pre-existing rocks or organic matter), and are often porous and permeable.
• They are stratified and can be split along the layers.

(b) Two ways sedimentary rocks can be formed:

• Mechanically (clastic/detrital formation): rocks are weathered and eroded into fragments; these sediments are transported by water, wind or ice, deposited in layers, then compacted and cemented over time into rock such as sandstone and shale.
• Organically (biological formation): the remains of living things accumulate and are compacted, e.g. the shells and skeletons of sea organisms forming limestone/chalk, or plant remains forming coal. (Chemically formed sedimentary rocks, e.g. rock salt from evaporation, are also acceptable.)

Akọwa Nkọwa

(a) Four ways water transport is important in international trade:

• Carriage of bulky and heavy goods: ships can carry large quantities of bulky, low-value goods (crude oil, grains, ores, timber) cheaply over long distances between countries.
• Cheapest means over long distances: the low cost per tonne-kilometre reduces freight charges and makes internationally traded goods cheaper.
• Links continents and distant markets: oceans connect nations separated by seas, allowing trade between continents that land transport cannot reach.
• Large carrying capacity: a single vessel moves far more than road or rail, so huge volumes of imports and exports can be handled at ports.

(b) Four limitations of water transportation:

• It is slow compared with air transport, so perishable and urgent goods are delayed.
• It is restricted to coasts, navigable rivers and lakes and cannot serve inland areas directly.
• Navigation can be hindered by natural hazards such as storms, fog, ice, shallow water, rapids, waterfalls and silting.
• It requires heavy capital for building ships, ports, harbours, canals and dredging, and delays occur during loading and unloading.

(c) Solutions to any two of the problems above:

• Restriction to waterways / reaching inland areas: construct canals and dredge rivers to extend navigable routes and link water transport with road and rail (multimodal transport).
• Natural hazards / shallow water and silting: carry out regular dredging, install modern navigation aids (lighthouses, buoys, radar, GPS) and weather forecasting to guide ships safely.

Akọwa Nkọwa

(a)(i) Definition of Environmental Resources

Environmental resources are the natural materials and features of the environment that are of value and can be used by man to satisfy his needs, either directly or after processing. They include living (biotic) and non-living (abiotic) components supplied by nature.

(a)(ii) Two types of environmental resources other than water:

• Mineral resources (e.g. petroleum, coal, iron ore, gold, limestone).
• Vegetation/forest resources (e.g. timber, medicinal plants). (Also acceptable: soil, wildlife, air, solar energy.)

(b) Four ways water is important as an environmental resource:

• Domestic use for drinking, cooking, washing and general household needs.
• Agriculture for irrigation of crops and for watering livestock.
• Industry and power: water is used for cooling, processing and to generate hydro-electric power.
• Transport, fishing and trade: rivers, lakes and seas provide navigable routes and support fisheries. (Also: recreation and tourism.)

(c) Two problems arising from degradation of water resources:

• Water-borne diseases and health hazards: polluted water spreads cholera, typhoid and dysentery, raising death and sickness rates.
• Scarcity of clean water and loss of aquatic life: pollution and drying up reduce supply for domestic, farm and industrial use and destroy fish and other organisms, threatening livelihoods.

Akọwa Nkọwa

(a) Three conditions that favour fruit farming in the Mediterranean Regions of Africa:

• Suitable Mediterranean climate: hot, dry, sunny summers ripen the fruit while the mild, wet winters supply moisture, ideal for citrus, grapes, olives and figs.
• Fertile, well-drained soils: the rich soils of the coastal lowlands and river valleys support healthy fruit trees.
• Availability of irrigation water and gentle relief: rivers and irrigation supply water in the dry summer, and the level to gently sloping land is easy to cultivate. (Long hours of sunshine and skilled labour are also acceptable.)

(b) Four problems facing fruit farming in the Mediterranean Regions of Africa:

• Summer drought and shortage of water, making irrigation necessary and costly.
• Pests and diseases that attack the trees and fruit, reducing yield and quality.
• Occasional hazards such as hot, dry winds (sirocco), frost or hail that damage crops.
• Marketing problems: the fruit is perishable, and there is competition, price fluctuation and the cost of storage and transport to distant markets.

(c) Three ways fruit farming is of economic importance to the Mediterranean Regions:

• Foreign exchange earned from exporting citrus, grapes, olives and wine.
• Employment and income for farmers, pickers, processors and traders.
• Raw materials for industry (wine-making, canning, olive oil and juice), which promotes agro-industrial and general economic development.

Akọwa Nkọwa

(a) Sketch map of Africa

Key locations: River Niger in West Africa; River Zambezi in south-central Africa; Lake Victoria in East Africa; the Tropic of Cancer at 23½°N; the Tropic of Capricorn at 23½°S; the Atlas Mountains in north-west Africa; the Niger Delta petroleum field in Nigeria; and the Witwatersrand goldfield in South Africa.

(b) Economic importance of petroleum in the Niger Delta, Nigeria

1. Petroleum earns substantial foreign exchange through the export of crude oil and petroleum products.
2. It provides revenue to the government through taxes, royalties, rents and export duties.
3. It creates employment for geologists, engineers, refinery workers, tanker drivers, construction workers and many other workers.
4. It supplies energy and fuel for transport, industries, electricity generation and households.
5. It provides raw materials for petrochemical industries, including the manufacture of plastics, fertilisers, lubricants, bitumen and synthetic fibres.
6. It promotes the development of related industries such as oil refineries, petrochemical plants, liquefied natural gas plants and servicing companies.
7. It has encouraged the provision of infrastructure such as roads, ports, pipelines, airports, electricity and water supply in oil-producing areas.
8. It attracts foreign capital, technical skills and technology into the area.

Akọwa Nkọwa

Hot Desert Climate

(a) Location

Hot deserts are mainly found between about 15° and 30° north and south of the Equator, especially on the western sides of continents and in continental interiors. They occur in the belt of subtropical high pressure where dry, descending air prevents cloud formation and rainfall.

Examples include the Sahara in North Africa, Arabian Desert, Thar Desert, Namib and Kalahari deserts in southern Africa, Atacama Desert in South America, deserts of south-western USA, and the Great Australian Desert.

(b) Characteristic features

The climatic graph below shows the very low rainfall and persistently high temperature of a hot desert climate.

Monthly climatic data represented in the graph

Month	J	F	M	A	M	J	J	A	S	O	N	D
Temperature (°C)	17	20	25	30	34	38	40	39	35	29	22	18
Rainfall (mm)	3	2	2	1	0	0	1	2	4	5	3	2

• Temperatures are high throughout the year. Day temperatures may exceed 38°C and may rise to about 50°C in some deserts.
• There is a large diurnal range of temperature: days are intensely hot, while nights may be cold because clear skies permit rapid loss of heat by radiation.
• Rainfall is very low, unreliable and usually below 250 mm annually. In the graph, the annual total is only 25 mm.
• When rain falls, it is often convectional, sudden and violent, producing flash floods in dry valleys.
• Skies are generally clear, sunshine and solar radiation are intense, and evaporation is high.
• Relative humidity is low, often about 30% or less.
• Dry descending air of the subtropical high-pressure belt produces arid conditions. Cold currents, such as the Canary and Benguela currents, intensify aridity along some west coasts.
• Dust storms and sand storms are common. Soils are mainly sandy, stony or rocky and have little humus.

(c) Vegetation

• Vegetation is sparse, scattered and widely spaced because of inadequate moisture.
• The plants are mainly xerophytes, that is, plants adapted to drought. Common examples are cactus, acacia, thorny shrubs, grasses and herbs.
• Plants often have long tap roots or widespread shallow roots to obtain scarce water.
• Some have thick, fleshy or succulent stems for storing water.
• Leaves are small, waxy, leathery, hairy, needle-like, or reduced to spines or thorns, thereby reducing transpiration.
• Date palms occur around oases where underground water is available. Some plants are salt-tolerant halophytes.
• Annual grasses and herbs grow rapidly after short periods of rain, flower, produce seeds and die before the next dry period.

(d) Human activities

• Nomadic pastoralism: camels, goats and sheep are reared as herders move in search of water and pasture.
• Oasis and irrigated farming: dates, vegetables, wheat, millet, sorghum and other crops are grown where river water, wells or underground water is available.
• Mining and petroleum production: oil, natural gas, phosphates, salt and other minerals are extracted in many desert areas.
• Trading and transport: caravan routes and modern roads link settlements and move goods across deserts.
• Tourism and energy generation: desert scenery attracts tourists, while the abundant sunshine favours solar-energy projects.