WAEC SSCE - Geography - 2005

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A country is said to be landlocked when it does not have any direct access to the sea. This means that the country is surrounded by other countries and does not have any coastline. As a result, it cannot use ports for trading or transportation by sea, and must rely on other countries or modes of transportation, such as roads, railways, or air travel.

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Soil erosion is the process of soil movement by water or wind. It is a serious problem in agriculture because it can lead to reduced soil fertility and crop yields. Out of the four options given, three of them can lead to soil erosion. Ploughing of land up and down slope can cause soil erosion because it allows water to flow down the slope, carrying soil with it. Persistent cultivation of crops in regions of inadequate rainfall can also cause soil erosion because the lack of rainfall means there is less vegetation to protect the soil from being washed away by water or blown away by wind. Over-cropping can lead to soil erosion because it means the soil is being used continuously without being given enough time to rest or recover. This can result in the soil becoming depleted of nutrients and more susceptible to erosion. However, mixed cropping can actually help to prevent soil erosion. By planting different crops together, it can create a more diverse and complex root system which helps to hold the soil in place and reduce the risk of erosion. Additionally, mixed cropping can also help to reduce the need for pesticides and fertilizers, which can also have negative impacts on the soil. In conclusion, options 1, 2, and 3 can lead to soil erosion while (mixed cropping) can help to prevent it.

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Weathering, erosion, transportation, and deposition are processes of denudation. Denudation is the gradual wearing down of the Earth's surface through the processes of weathering, erosion, transportation, and deposition. Weathering is the breakdown of rocks and minerals at or near the Earth's surface, caused by physical, chemical, and biological processes. Erosion is the removal of weathered material by the action of water, wind, or ice. Transportation is the movement of eroded material by these same agents. Deposition is the settling of this material in a new location. Together, these processes can shape the Earth's surface, creating landforms such as valleys, canyons, and deltas. They can also contribute to the formation of soils and the cycling of nutrients in ecosystems. Denudation is an important geological process that has been shaping the Earth's surface for millions of years.

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The correct sequence in a food chain is: plants -> herbivores -> carnivores -> decomposers. Plants are at the bottom of the food chain because they are producers that convert energy from the sun into food through photosynthesis. Herbivores, such as cows or deer, eat the plants to obtain energy and nutrients. Carnivores, such as lions or eagles, eat the herbivores to obtain energy and nutrients. Finally, decomposers, such as bacteria and fungi, break down the dead bodies of plants and animals, returning nutrients to the soil so that plants can grow again. This sequence of plants -> herbivores -> carnivores -> decomposers is called a food chain. Each level of the food chain is called a trophic level. The higher up the trophic levels you go, the fewer organisms there are because energy is lost at each level due to respiration, waste production, and other factors. In summary, the correct sequence in a food chain is: plants -> herbivores -> carnivores -> decomposers, with each level being a trophic level that is characterized by a specific group of organisms that obtain energy and nutrients from the previous level.

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Rural-urban migration is the movement of people from rural areas to urban areas in search of better living conditions and opportunities. One effect of rural-urban migration on the source region is rural depopulation. This means that people are leaving the rural areas, causing a decrease in the population. As a result, there will be a decrease in the demand for goods and services, which may lead to a decline in the economy of the rural areas. The decrease in population also means that there will be a decrease in the workforce, which may affect the productivity and development of the rural areas. Additionally, rural depopulation may lead to a decrease in the social and cultural values of the area as the younger generations migrate to urban areas in search of better opportunities.

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The shape of the ocean floor does not affect the salinity of the oceans. The salinity of seawater is primarily influenced by the amount of dissolved salts in it. The ocean floor, on the other hand, refers to the physical features of the seafloor, including the depth, slope, and shape of the ocean basins. While the shape of the ocean floor can affect ocean currents and their mixing patterns, it does not directly affect the amount of salt in seawater. The other factors listed, such as the rate of evaporation, the degree of water mixing by currents, and the amount of fresh water added by rain, all have a direct impact on the salinity of the oceans.

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A river capture occurs when a river channel diverts its course and begins to flow into a different river system. The diversion can occur due to various factors, such as erosion or tectonic movement. Misfit river refers to a river that does not seem to fit the valley it is flowing through. It may indicate a river capture, as the river has not yet adjusted to its new course. An elbow of capture is a sharp bend in a river that marks the point where the river is actively eroding the headward region of another stream. This is a clear indicator of a river capture in progress. A wind gap is a notch or pass in a mountain ridge that has no surface stream flowing through it. It can be a result of a river capture, where the river erodes the passageway, but subsequently diverts its course, leaving the gap dry. River terraces are flat, bench-like surfaces that occur along river valleys. They are usually formed by the river eroding its channel and leaving the old floodplain behind. While river terraces can occur for various reasons, they are not directly associated with a river capture. Based on the above explanations, options (1) I,III and IV is the correct answer as misfit river, elbow of capture, and wind gap are all features associated with river capture. is incorrect, as river terraces are not directly associated with a river capture. is also incorrect, as river terraces are excluded. Finally, is incorrect, as it excludes misfit river, which can be an important indicator of a river capture in progress.

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Coastlines washed by cold currents normally have scanty rainfall. This is because cold ocean currents originate from polar regions, where the air is cold and dry. As these currents move towards the equator, they cool the overlying air, which causes any moisture in the air to condense and form clouds. However, since the air is cold and has little moisture to begin with, the resulting rainfall is usually minimal. Therefore, coastlines that are washed by cold ocean currents generally experience low levels of rainfall.

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A demerit of low population density is inadequate labor force. Low population density means there are fewer people in a given area, which can lead to a shortage of skilled workers for businesses and industries that may be located in the area. This can lead to a lack of economic development and growth, as businesses may not be able to find the necessary workforce to expand or operate efficiently. In turn, this can limit job opportunities and potentially lead to lower overall incomes for residents.

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One of the major characteristics of heavy industries is that they require high capital outlay. Heavy industries are those industries that involve large-scale production and manufacture of heavy goods such as steel, chemicals, and heavy machinery. These industries require a significant amount of capital investment in terms of machinery, infrastructure, and technology to set up and operate. The cost of production is high due to the use of expensive equipment, and the production process is usually capital-intensive. Therefore, heavy industries require substantial financial resources to start and sustain their operations. The need for high capital outlay is one of the main reasons why heavy industries are considered to be critical drivers of economic growth in many countries, as they can stimulate investment and job creation.

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The statement describes a warm and dusty weather condition that comes from the Sahara and extends farthest to the south in January. This weather condition is known as the Tropical Continental airmass.

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Hydraulic action is not a process of wind erosion. Wind erosion is a process whereby the wind picks up and carries away loose materials such as sand, silt, and clay from the Earth's surface. The four main processes of wind erosion are abrasion, attrition, deflation, and saltation. Abrasion occurs when the wind carries particles that scrape and scour the Earth's surface, while attrition is the wearing down of particles as they collide with each other or other materials. Deflation occurs when the wind removes loose particles from the Earth's surface, leaving behind a depression or hollow. Saltation is the movement of particles by the wind in a hopping or bouncing motion. Hydraulic action, on the other hand, is a process of water erosion, whereby the force of water breaks down and wears away rocks and other materials. Therefore, hydraulic action is not a process of wind erosion.

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The most abundant gas in the Earth's atmosphere is nitrogen. It makes up about 78% of the air we breathe, while oxygen, the gas we need to survive, only makes up about 21%. Argon is present in very small amounts, about 0.93%, and hydrogen is even less common, at less than 0.1%.

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The biosphere is a term used to describe the portion of the Earth where life exists. It includes all living organisms, such as plants, animals, and microorganisms, as well as their interactions with each other and their environment. Therefore, the correct answer is rocks. Rocks are not living things and do not contribute to the biosphere, although they can provide habitat for living organisms. In summary, the biosphere includes all living organisms and their interactions with the environment, but does not include non-living things such as rocks.

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Coastal erosion can be prevented by the stabilization of sandy and muddy beaches by coastal vegetation. This is because coastal vegetation, such as plants and trees, help to anchor the soil in place and reduce the impact of waves and tides. This helps to prevent erosion by holding the soil in place and reducing the amount of sediment that is washed away by the water. In addition to stabilizing the soil, coastal vegetation also helps to absorb the energy of waves and tides, reducing their impact on the shoreline. This can help to protect the coast from damage caused by storms and other extreme weather events. In summary, coastal erosion can be prevented by stabilizing sandy and muddy beaches through the planting of coastal vegetation. This helps to anchor the soil in place and reduce the impact of waves and tides, protecting the coast from erosion and damage.

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The most distant planet from us is Pluto. Pluto used to be considered the ninth planet in our solar system until it was reclassified as a dwarf planet in 2006. Pluto is located in the Kuiper Belt, a region of the solar system beyond the orbit of Neptune. Because of its location in the Kuiper Belt, Pluto's distance from Earth varies depending on where it is in its orbit. At its closest approach to Earth, Pluto is still over 2.6 billion miles away. At its farthest point from Earth, Pluto can be as far as 4.67 billion miles away. This makes Pluto the most distant planet (dwarf planet) from us in the solar system.

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Six's thermometer is a type of thermometer that is commonly used to measure the minimum and maximum temperature of a particular location over a period of time. It consists of a U-shaped glass tube that is filled with a special liquid, usually mercury or alcohol, which expands and contracts as the temperature changes. The tube is attached to two separate scales, one on either side, which record the highest and lowest temperature reached during the period of observation. Thus, Six's thermometer provides a simple and reliable way to measure both the minimum and maximum temperature at a given location.

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The distance of planet Mercury from the sun is about 57 million kilometers (km). Mercury is the planet closest to the sun in our solar system, and its distance from the sun varies depending on its position in its orbit. At its closest approach to the sun (perihelion), Mercury is about 46 million km away, while at its farthest point (aphelion), it is about 70 million km away. On average, Mercury is about 57 million km away from the sun.

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The latitudes which mark the limits of the apparent movement of the overhead sun are the Tropics of Cancer and Capricorn. The Tropics of Cancer and Capricorn are two imaginary lines located at approximately 23.5 degrees north and south of the equator, respectively. These latitudes mark the farthest points north and south where the sun can appear directly overhead during the year. When the sun appears directly overhead at noon, it casts no shadows, and this happens twice a year in each tropic. These points are also known as the solstices and are used to mark the beginning of summer and winter. The Tropic of Cancer is the northernmost latitude where the sun can appear directly overhead, while the Tropic of Capricorn is the southernmost latitude where the sun can appear directly overhead. The area between these two lines is known as the tropics, and it is characterized by warm temperatures and a high amount of precipitation. The Tropics of Cancer and Capricorn play an important role in determining weather patterns and climate around the world.

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Marble, slate, and gneiss are all examples of metamorphic rocks. Metamorphic rocks are formed when existing rocks are subjected to high pressure, heat, and/or chemical changes over long periods of time. Marble is formed from limestone or dolomite that has been exposed to heat and pressure. Slate is formed from shale or mudstone that has undergone intense pressure and heat, causing the minerals to recrystallize into thin layers. Gneiss is formed from pre-existing rocks such as granite, which have undergone high heat and pressure causing the minerals to rearrange into bands. In summary, all three options are examples of metamorphic rocks, which are formed by the alteration of existing rocks due to high pressure, heat, and/or chemical changes over time.

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The phenomenon where there is a regular pattern of wind blowing from the sea towards the land during the day, and from the land towards the sea during the night on a large scale (continent-scale) is known as "monsoons". During the day, the land heats up faster than the sea, causing the air above the land to rise and cooler air from the sea to move in, resulting in a sea breeze. At night, the land cools down faster than the sea, causing the air above the sea to rise and cooler air from the land to move in, resulting in a land breeze. This phenomenon is particularly prominent in the Indian subcontinent and Southeast Asia, where it causes significant seasonal changes in temperature, humidity, and precipitation. In the summer, the warm, moist air from the Indian Ocean is drawn towards the land, resulting in heavy rainfall and flooding in some regions. In the winter, the cooler, drier air from the land moves towards the Indian Ocean, resulting in dry and clear weather. In conclusion, the phenomenon of regular land and sea breezes on a continental scale is known as "monsoons". Typhoons, fohn, and chinook are different weather-related phenomena that are not related to monsoons.

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The instrument used for measuring the speed of wind is called a cup anemometer. A cup anemometer typically consists of three or four cups mounted on a horizontal axis. The cups are designed to catch the wind and spin around the axis. The speed of the cups' rotation is proportional to the speed of the wind, and this rotation is measured and recorded by the anemometer. Cup anemometers are widely used to measure wind speed in a variety of applications, including weather forecasting, aviation, and wind energy production. They are simple to use and provide accurate measurements, making them a valuable tool for those who need to monitor wind conditions.

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Heavy rainfalls are often associated with cumulonimbus clouds. Cumulonimbus clouds are large and vertically developed clouds that are capable of producing thunderstorms, heavy rain, hail, and even tornadoes. They form in unstable atmospheric conditions where warm, moist air rises rapidly, cools, and condenses into clouds. The top of the cumulonimbus cloud often has a distinctive anvil shape, which is created by the strong winds at high altitudes that blow the top of the cloud into a flat shape. Heavy rainfall occurs when the warm, moist air within the cumulonimbus cloud rises and cools, causing the water droplets within the cloud to condense into raindrops. As the raindrops become too heavy for the updrafts within the cloud to support, they fall to the ground as heavy rain. Cumulonimbus clouds are often associated with thunderstorms, lightning, and strong winds, making them a potentially dangerous weather phenomenon.

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A continental shelf is economically important because it is a good fishing ground. Continental shelves are the flat underwater areas that extend from the shoreline into the ocean, and they are relatively shallow compared to the rest of the ocean. These shallow waters support a diverse range of marine life, including fish, crustaceans, and shellfish, which makes them ideal for commercial and recreational fishing activities. Fishing on continental shelves can be a significant source of income for countries with extensive coastlines and a thriving fishing industry. In addition to fishing, continental shelves also contain oil and gas reserves that can be economically valuable.

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When a warm ocean current meets a cold ocean current, they produce fog. This happens because the warm air above the warm ocean current rises and cools as it meets the cold air above the cold ocean current. This cooling causes the moisture in the warm air to condense into tiny water droplets, which form a mist or fog. The temperature difference between the warm and cold currents also creates a zone of instability in the atmosphere, which can lead to other weather phenomena like storms or squalls, but not hail.

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Latitude is a geographic coordinate that specifies the north-south position of a point on the Earth's surface. The equator is an imaginary line that circles the Earth at 0° latitude, dividing the Earth into the Northern Hemisphere and Southern Hemisphere. Therefore, if a town is located at latitude 14°N, it means that it is located 14 degrees north of the equator. To determine the distance of the town from the equator, we need to know how many kilometers correspond to one degree of latitude. The Earth's circumference is approximately 40,000 kilometers, and it is divided into 360 degrees of longitude (east-west) and latitude (north-south). Therefore, the distance corresponding to one degree of latitude can be approximated by dividing the Earth's circumference by 360 degrees. Distance per degree of latitude = 40,000 km / 360 = 111.11 km/degree To find the distance of the town located at 14°N from the equator, we can simply multiply the distance per degree of latitude by the latitude of the town: Distance from equator = 111.11 km/degree * 14 degrees = 1,555 km Therefore, the answer is: 1555 km.

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The vegetation type associated with the sub-equatorial type of climate is the rainforest. The sub-equatorial climate is characterized by high temperatures, high humidity, and heavy rainfall throughout the year. These conditions are ideal for the growth and development of lush, dense vegetation, such as the tall trees, vines, and shrubs found in tropical rainforests. Rainforests are home to a wide variety of plant and animal species, and they play a crucial role in maintaining the Earth's biodiversity and regulating the planet's climate. Therefore, the rainforest is the vegetation type that is most closely associated with the sub-equatorial climate.

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The Mediterranean type of climate is best suited for fruit growing. This is because this type of climate is characterized by hot, dry summers and mild, wet winters, which creates ideal conditions for the growth and ripening of fruits such as grapes, olives, figs, citrus fruits, and pomegranates. Additionally, the fertile soils found in Mediterranean regions, combined with the long periods of sunshine and relatively low humidity, provide a perfect environment for fruit trees to thrive. While vegetable gardening can also be successful in this type of climate, it requires careful irrigation and soil management due to the lack of rainfall during the summer months. Cattle rearing and rice cultivation, on the other hand, typically require more water and may be more suitable in areas with higher rainfall or more temperate climates.

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The vegetation type that is found only in the Northern hemisphere is the Tundra. Tundra is a type of biome that is found in areas with very low temperatures, usually in the Arctic regions. It is characterized by very cold winters, short summers, and a layer of permafrost (permanently frozen soil) underneath the ground. The vegetation in the tundra is usually made up of low-growing shrubs, mosses, and lichens, since the cold temperatures and permafrost make it difficult for larger plants to grow. On the other hand, tropical grasslands and equatorial forests are found in tropical regions, both in the Northern and Southern hemispheres. Mediterranean vegetation, also known as scrubland or chaparral, is found in areas with a Mediterranean climate, which can be found in both the Northern and Southern hemispheres.

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(a) Three plantation crops in Africa

• Cocoa.
• Oil palm.
• Rubber.

(Others acceptable: coffee, tea, sugar cane, banana, sisal.)

(b) Four ways in which plantation agriculture is important

• Foreign-exchange earnings: plantation crops such as cocoa, coffee, tea and rubber are exported and bring in foreign currency.
• Employment: plantations provide large-scale jobs for many workers in growing, harvesting and processing.
• Raw materials for industry: they supply factories (for example oil palm for oil and margarine, rubber for tyres), encouraging industrial growth.
• Development of infrastructure and rural areas: roads, railways, health and housing facilities are provided, and the crops widen and diversify the economy.

(c) Three differences between plantation agriculture in West Africa and East Africa

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(a) Advantages and disadvantages of water transport

Three advantages:

• Cheapest for bulky goods: ships and barges can carry very large, heavy cargoes (oil, grain, ores) over long distances at low cost per tonne.
• Natural, ready-made routes: seas, oceans, rivers and lakes provide free routeways, so little construction is needed compared with roads and railways.
• Low fuel and maintenance cost per unit carried, and it links many countries and continents, promoting international trade.

Three disadvantages:

• Very slow, so it is unsuitable for perishable goods and urgent deliveries.
• Limited routes: it can serve only places on or near navigable water, and needs feeder transport to reach inland destinations.
• Affected by weather and needs costly port facilities; storms, fog, ice and shallow water can delay or endanger vessels.

(b) Four factors that hinder the use of water transport

• Shallow water, rapids, waterfalls and sand bars that block or interrupt navigation on rivers.
• Seasonal changes in water level (low water in the dry season, floods in the wet season) that make some rivers navigable only part of the year.
• Silting of channels, ports and river mouths, and the growth of aquatic weeds, which obstruct vessels.
• Freezing of rivers and lakes in cold regions, and adverse weather such as storms and fog; also the high cost of dredging and building/maintaining harbours.

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(a) Three characteristics of forest vegetation

• Trees dominate and grow tall, forming a closed or nearly closed canopy so that the ground receives little sunlight.
• Layered (storeyed) structure, with emergent tall trees, a main canopy layer, and lower shrub and ground layers.
• Dense and varied plant life, many species of hardwood trees mixed together, with climbers (lianas), epiphytes and, in wet forests, broad evergreen leaves; the trees often have buttress roots.

(b) Three ways vegetation is important as an environmental resource

• Protects the soil and water: it binds the soil with roots, checks erosion, and helps rainfall to soak in, keeping rivers and springs supplied.
• Regulates climate and air quality: plants take in carbon dioxide and give out oxygen, add moisture to the air, and moderate temperature, reducing the greenhouse effect.
• Habitat and raw materials: it provides a home for wildlife and supplies timber, fuel wood, medicines, fruits and grazing, which support human livelihood.

(c) Two problems from over-utilization of vegetation resources

• Deforestation leading to soil erosion and loss of fertility, flooding, silting of rivers and eventual desertification.
• Destruction of habitat and loss of biodiversity, so that wildlife and useful plant species become scarce or extinct, and the climate is disturbed.

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(a) Meaning of error of closure

In a closed traverse the survey lines are run round an area and should end exactly at the starting point. The error of closure is the small gap or difference between the true starting point and the point at which the survey actually closes when it is plotted, that is, the amount by which the survey fails to close back onto its origin. It shows the total accumulated error of the survey.

(b) Four sources of error of closure in a closed traverse survey

• Instrumental errors: a faulty or wrongly graduated chain/tape, a badly adjusted compass or theodolite, or a bent ranging pole.
• Errors in measuring angles/bearings: wrong reading of the compass or theodolite, local magnetic attraction affecting the needle, or failing to take the back bearing.
• Errors in measuring distances: inaccurate chaining, sag or stretch in the tape, sloping ground not corrected to the horizontal, or miscounting the chains/arrows.
• Personal (human) and plotting errors: careless booking, mistakes in recording figures, and errors made when plotting the survey on paper (wrong scale, poor drawing).

(c) Two measures to avoid an error of closure

• Check and adjust the instruments before use and take readings carefully, repeating and averaging measurements of both distances and angles.
• Apply proper field checks such as measuring back bearings, using check lines/tie lines, and keeping away from sources of magnetic disturbance; any small residual error is then distributed by adjustment (for example the Bowditch rule) when plotting.

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(a) Printing the letters on the map

• Conical Peak (CP): print in the north-east, on the hill whose contour rings are roughly circular and close together, tapering to a single high point (the ground above 750 ft).
• Narrow River Valley (NRV): print in the south-west, where the contours form a sharp V enclosing a stream.
• Even Slope (ES): print in the eastern part, where the contours are equally spaced, showing a uniform gradient.

(b) Gradient of the minor road from the Sabongidda junction to the church in Aviosi

Height at the Sabongidda road junction \(=250\text{ ft}\); height at the church in Aviosi \(=675\text{ ft}\).

Road distance measured on the map \(=5.9\text{ in}\). Since \(1\text{ mile}=5280\text{ ft}\) and the scale is 1:50,000 (1.25 in to 1 mile):

The gradient of the minor road is 1 in 58 (1:58).

(c) Location and functions of Uhomora

Location: Uhomora lies in the south-east of the map, on the spur between two tributaries of River Onwan, on level ground between the 250 ft and 300 ft contours.

Functions:

• It is a nodal town, being the meeting point of two minor roads.
• It performs a medical function, shown by the hospital and dispensary.
• It performs an educational function, shown by the schools.
• It performs a religious function, shown by the churches.

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(a) Sketch map of Nigeria showing the Eastern Railway Line

Key: solid line = Eastern Railway Line. The four stations shown are Port Harcourt, Aba, Enugu and Makurdi.

(b) Advantages of rail transport in Nigeria

1. It is a relatively cheap means of carrying bulky and heavy goods, such as cement, petroleum products, minerals and farm produce, over long distances.
2. It has a high carrying capacity: a train can convey many passengers or large quantities of freight at one time.
3. It links distant parts of the country, promotes trade and national integration, and opens up areas served by the railway.

(c) Limitations of rail transport in Nigeria

1. Railways operate on fixed tracks and fixed schedules; they do not provide door-to-door service, so road transport is needed at both ends of a journey.
2. The railway network is limited, with many old, poorly maintained tracks, locomotives and coaches, leading to breakdowns and delays.
3. Construction, rehabilitation and maintenance of railway lines are very costly, especially where bridges, drainage works and difficult terrain are involved.

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(a) Meaning of settlement

A settlement is any place, ranging from a single homestead to a large city, where people live and build their dwellings and carry on their activities. It is the way in which people group their houses and occupy a piece of land. Settlements may be temporary or permanent, and are broadly divided into rural (village) and urban (town/city) types.

(b) Four characteristics of an urban settlement

• Large population living at high density, so houses are close together and often storeyed.
• Non-agricultural occupations dominate: most people work in industry, commerce, services and administration rather than farming.
• Well-developed infrastructure and services: good roads, electricity, pipe-borne water, schools, hospitals, banks, markets and recreational facilities.
• Complex functions and land use with distinct residential, commercial, industrial and administrative zones, and a wide range of social groups.

(c) Four functions an urban settlement performs for a rural settlement

• Market/commercial centre: the town buys the farm produce of the villages and supplies them with manufactured goods.
• Provision of services: it offers higher-order services such as hospitals, secondary and tertiary schools, banks and administrative offices used by rural people.
• Source of employment: it absorbs surplus rural labour, providing jobs in industries and services.
• Centre for processing and distribution: it processes raw materials from the countryside and acts as a transport/collecting hub linking the villages to wider markets; it also supplies farm inputs (tools, fertiliser) and spreads new ideas and technology.

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(a) Meaning of karst topography

Karst topography is the distinctive scenery that develops in regions of thick, well-jointed limestone (or other soluble rock such as dolomite or chalk) as a result of solution (carbonation) weathering. Rainwater, being a weak carbonic acid, dissolves the limestone along its joints and cracks, producing a landscape of underground drainage with characteristic surface and underground features. The name comes from the Karst region of the former Yugoslavia.

(b) Four features found in karst regions

• Swallow holes (sink holes / dolines).
• Limestone caves and caverns.
• Stalactites and stalagmites (in the caves).
• Limestone pavements with clints and grikes; also gorges and underground streams.

(c) Five characteristics of karst regions

• Underground drainage: surface streams disappear down swallow holes and flow underground, so the surface is often dry.
• Presence of caves and caverns formed by solution beneath the surface, decorated with stalactites (hanging from the roof) and stalagmites (rising from the floor).
• Bare, rocky surface with limestone pavements (clints separated by grikes) and thin, poor soils, so vegetation is scanty.
• Numerous joints and cracks in the well-bedded limestone along which solution takes place; enlarged joints and dolines are common.
• Deep gorges and steep-sided valleys formed where cave roofs collapse, and re-emergence of streams as springs at the foot of the limestone.

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(a) Definitions

• (i) Optimum population: the ideal population size that, with the available resources and level of technology, gives the highest standard of living (the greatest output and welfare per person). It is neither too many nor too few people for the resources.
• (ii) Over-population: a situation in which the population is too large for the available resources and technology to support at a reasonable standard of living, so that resources are over-stretched and welfare falls.
• (iii) Population density: the average number of people living on each unit area of land, usually expressed as persons per square kilometre. It is found by dividing the total population by the total land area.

(b) Population density of country Q

\[\text{Population density} = \frac{\text{Total population}}{\text{Land area}}\]

\[= \frac{4\,000\,000}{400\,000} = 10 \text{ persons per km}^2\]

Population density = 10 persons per km² (a low/sparse density).

(c) Four disadvantages of this low population density on the economy of the country

• Shortage of labour: too few people to work the farms, mines and industries, so resources remain unused or under-developed.
• Small home market: low demand for goods and services discourages large-scale production and investment.
• High cost of infrastructure per head: roads, water, electricity and other services are expensive to provide and maintain for a thinly spread population.
• Weak revenue and slow development: a small population yields little tax revenue and a small workforce, so defence, government services and the general pace of economic growth suffer.

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(a) Four factors that determine the temperature of a place

• Latitude: places near the Equator receive the Sun's rays more directly and are hotter than places near the poles where the rays are slanting.
• Altitude: temperature falls with height (about \(6.5^\circ C\) per 1000 m), so highlands are cooler than lowlands on the same latitude.
• Distance from the sea (continentality): coastal places have milder, more even temperatures because the sea heats and cools slowly, while inland places have hotter days and colder nights.
• Ocean currents and prevailing winds: warm currents/winds raise temperature and cold currents/winds lower it (also acceptable: cloud cover, nature of the surface/vegetation, and aspect).

(b) Koppen's climatic classification

(i) The two climatic elements used as the basis:

• Temperature and Precipitation (rainfall).

(Koppen combined these with the natural vegetation of each region.)

(ii) The main climatic groups in Koppen's classification:

• A - Tropical (hot, wet) climates.
• B - Dry (arid and semi-arid/desert and steppe) climates.
• C - Warm temperate (mild, mid-latitude) climates.
• D - Cold temperate (cold, snowy, mid-latitude/continental) climates.
• E - Polar (cold, ice and tundra) climates.

(Some versions add H - Highland/mountain climates.)

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(a) Longitude of Addis Ababa

The Earth turns \(360^\circ\) in 24 hours, so \(1\) hour of time = \(15^\circ\) of longitude.

Time difference between Addis Ababa (12:00 noon) and London (08:00 GMT):

\[12:00 - 08:00 = 4 \text{ hours}\]

Longitude difference:

\[4 \times 15^\circ = 60^\circ\]

Because Addis Ababa is ahead of GMT (its clock reads later than London's), it lies east of the Greenwich Meridian.

Addis Ababa is on longitude \(60^\circ E\).

(b) Explanatory notes

(i) Time zones: A time zone is a belt of the Earth's surface, about \(15^\circ\) of longitude wide, that keeps the same clock time. The world is divided into 24 such zones (each 1 hour apart) so that places within a zone use one convenient standard time instead of a slightly different local time at every meridian.

(ii) Standard time: This is the single, uniform clock time adopted by a whole country or zone, usually based on a chosen central meridian. It saves the confusion of many local times; large countries that stretch across several meridians (such as the USA or Russia) adopt more than one standard time.

(iii) International Date Line: This is the imaginary line drawn mainly along the \(180^\circ\) meridian in the Pacific Ocean where the date changes. A traveller crossing it going westward (eastern to western hemisphere) gains a day (moves the calendar forward), while going eastward loses a day. The line is bent in places to avoid splitting land areas and island groups into two different dates.

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(a) Meaning of soil erosion

Soil erosion is the wearing away, loosening and removal of the top (surface) layer of the soil from one place to another by natural agents such as running water, wind, ice or waves, and often accelerated by human activities. It is most serious when the fertile topsoil is stripped away faster than it can be replaced.

(b) Notes on soil erosion

(i) Causes

• Heavy rainfall and steep slopes, which give fast-flowing run-off that carries soil away (sheet, rill and gully erosion).
• Removal of vegetation cover through deforestation, bush burning and overgrazing, leaving the soil bare and exposed.
• Poor farming methods such as ploughing up and down slopes, continuous cropping and shifting cultivation on fragile land.
• Strong winds in dry, bare areas that blow away loose soil particles.

(ii) Effects

• Loss of soil fertility as the nutrient-rich topsoil is removed, reducing crop yields.
• Formation of gullies and badlands that destroy farmland, roads and buildings.
• Silting of rivers, dams and reservoirs by the eroded material, causing flooding and shortening the life of dams.
• Desertification and migration as land becomes unproductive, forcing people to move away.

(iii) Methods of prevention

• Afforestation and re-vegetation to bind the soil with roots and break the force of rain and wind.
• Contour ploughing, terracing and strip cropping on slopes to slow down run-off.
• Cover cropping, mulching and crop rotation to keep the soil covered and maintain fertility.
• Building drainage channels, check dams and planting wind breaks (shelter belts), and controlling bush burning and overgrazing.

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(a) Outline map of Africa showing mineral areas and towns

Key to the map

• Coal: Witbank (Emalahleni) coalfield, South Africa.
• Diamond: Kimberley, South Africa.
• Gold: Witwatersrand, South Africa.
• Towns named: Johannesburg in the Witwatersrand gold-mining area, and Kimberley in the diamond-mining area.

(b) Economic importance of the minerals to Africa

1. Gold and diamonds are exported to earn foreign exchange and increase government revenue.
2. Coal supplies energy for thermal power generation, rail transport and industries.
3. Mining provides employment and promotes the growth of mining towns, roads, railways and related industries.

(c) Problems associated with mining in Africa

1. Mining is capital-intensive: machinery, skilled labour and modern technology are often inadequate or expensive.
2. Mining causes environmental hazards such as land degradation, destruction of vegetation, open pits and pollution of water and air.

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(a) Outline map of Nigeria

(b) Size and location of Nigeria in relation to other countries of West Africa

Size

• Nigeria has a land area of about 923,768 km².
• It is the fourth largest country in West Africa by land area, after Niger, Mali and Mauritania.
• It occupies approximately one-seventh of the total area of West Africa.
• It is about four times the size of Ghana and about thirteen times the size of Sierra Leone.
• Its greatest east-west extent is about 1,300 km, while its north-south extent is about 1,100 km.
• It is the most populous country in West Africa.

Location

• Nigeria is located in the central/eastern part of West Africa, on the coast of the Gulf of Guinea.
• It lies approximately between latitudes 4°N and 14°N, and longitudes 3°E and 15°E.
• It is bounded by the Republic of Benin to the west, Niger to the north, Chad to the north-east across Lake Chad, and Cameroon to the east.
• To the south, Nigeria is bounded by the Atlantic Ocean, particularly the Gulf of Guinea. The Bight of Bonny lies along its south-eastern coast.

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(a) Sketch map of Africa showing two climatic areas

Key: green shading represents the Equatorial Climate in the Congo Basin; yellow shading represents the Hot Desert Climate in the Sahara.

(b) Characteristics of the Equatorial climate

1. Temperatures are high throughout the year, averaging about 26°C to 27°C.
2. The annual range of temperature is very small, usually about 2°C to 3°C.
3. Rainfall is heavy and well distributed throughout the year, often reaching about 200 cm or more annually.
4. There are usually two rainfall maxima, occurring around the equinoxes.
5. Most rainfall is convectional and commonly falls as heavy afternoon showers accompanied by thunder and lightning.
6. Relative humidity is high throughout the year and cloud cover is extensive.

(c) Economic importance of forest vegetation in Africa

1. It supplies valuable hardwood and timber for building, furniture making, paper and other industries.
2. Lumbering, sawmilling and the sale of timber provide employment, income and foreign exchange.
3. Forests provide fuel wood and charcoal for domestic and industrial use.
4. They supply raw materials and useful products such as rubber, fruits, nuts, palm products and medicinal herbs.
5. Forest reserves conserve wildlife and provide sites for tourism and recreation.

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(a) Meaning of Vulcanicity

Vulcanicity (vulcanism) is the process by which molten rock (magma), gases and other volcanic materials from the interior of the Earth are forced towards or onto the surface. It includes both intrusive activity (magma cooling within the crust to form features such as batholiths, dykes, sills and laccoliths) and extrusive activity (lava and materials reaching the surface to form volcanoes, lava plateaux and geysers).

(b) Formation and appearance of a volcanic (lava) plateau

Mode of formation: A volcanic plateau is formed by fissure eruptions. Very fluid, basic (basaltic) lava wells up quietly through long cracks or fissures in the crust rather than from a single vent. Because the lava is thin and runny, it spreads out over a wide area before cooling. Repeated eruptions build up layer upon layer of solidified lava (basalt) until a thick, extensive, raised, flat-topped upland is formed.

Appearance: It appears as a broad, high, almost level or gently undulating tableland with steep edges. It is built of horizontal sheets (layers) of basalt, and rivers later cut deep gorges and valleys into it. Examples include the Jos Plateau region basalts, the Ethiopian (Abyssinian) Plateau and the Deccan Plateau of India.

(c) Four effects of Vulcanicity

• Fertile soils: weathered volcanic (lava) materials give rich soils good for farming crops such as coffee, tea and cocoa.
• Landform and scenic value: it creates mountains, plateaux, crater lakes and hot springs that attract tourists.
• Mineral and geothermal resources: volcanic areas yield useful minerals and provide geothermal energy (steam/hot springs) that can generate electricity.
• Hazards: violent eruptions destroy life, farmland and property, and can cause earthquakes and force people to migrate.

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(a) Sketch map of Nigeria showing the industrial zones

Key: MW = Mid-West industrial zone; SE = South-East industrial zone; NC = North-Central industrial zone.

• Mid-West industrial zone: the Benin City, Sapele and Warri area. Important town: Warri.
• South-East industrial zone: the Enugu, Onitsha, Aba and Port Harcourt area. Important town: Aba.
• North-Central industrial zone: the Kaduna, Zaria and Jos area. Important town: Kaduna.

(b) Problems facing manufacturing industries in Nigeria

1. Erratic power supply: Industries spend heavily on generators and fuel when public electricity supply fails.
2. Inadequate capital: Many manufacturers cannot obtain sufficient long-term loans to buy machinery, raw materials or expand production.
3. Dependence on imported raw materials, machinery and spare parts: Foreign exchange shortages and high import costs raise production costs and interrupt production.

(c) Solutions to two of the problems

1. Improving power supply: Government and private power producers should expand electricity generation, transmission and distribution, while industries can use reliable alternative energy sources such as gas and solar power.
2. Providing capital and local inputs: Banks and government should provide low-interest industrial loans and tax incentives. Local raw materials should be developed, while local fabrication of machinery and spare parts should be encouraged to reduce import dependence.