WAEC SSCE - Geography - 2006 (Essay)

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(a) Environmental intervention

Environmental intervention refers to the actions, forces or processes (natural or human) that interfere with, alter or modify the natural environment. It is any deliberate or natural interference that changes the condition of the land, water, air or ecosystems.

(b) Types

(i) Natural intervention (two):

• Earthquakes and volcanic eruptions.
• Flooding, drought, erosion or storms.

(ii) Human intervention (two):

• Deforestation and bush burning.
• Mining, dam construction, farming and industrialisation.

(c) Five effects of natural and human interventions on the environment

• Soil erosion and land degradation, for example gully erosion from deforestation and heavy rain.
• Loss of vegetation and wildlife (loss of biodiversity) through clearing, burning and habitat destruction.
• Pollution of air, water and land from industries, mining and waste.
• Flooding and displacement of settlements from heavy rain, dam failure or blocked drainage.
• Desertification and climate change (drought, global warming), plus destruction of property and loss of lives from disasters such as earthquakes and volcanic eruptions.

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(a) The solar system

The solar system is the family of the Sun and all the heavenly bodies that revolve around it under the pull of its gravity. It consists of:

• The Sun at the centre, a star that gives light and heat and holds the system together by gravity.
• Eight planets which revolve around the Sun in elliptical orbits: Mercury, Venus, Earth, Mars, Jupiter, Saturn, Uranus and Neptune (Pluto is now classed a dwarf planet).
• Natural satellites (moons) that revolve around the planets, for example the Earth's Moon.
• Asteroids (minor planets) mostly found in a belt between Mars and Jupiter.
• Comets and meteors/meteoroids which also move round the Sun.

The inner planets (Mercury to Mars) are small and rocky; the outer planets (Jupiter to Neptune) are large gas giants.

(b) Four characteristics each

(i) Pluto

• It is the smallest body formerly counted as a planet and is now classified a dwarf planet.
• It is the farthest and coldest, lying at the outer edge of the solar system.
• It has a very long orbital period (about 248 Earth years to go round the Sun once).
• Its orbit is highly elliptical and tilted, sometimes bringing it inside Neptune's orbit; it has a moon (Charon).

(ii) Mercury

• It is the nearest planet to the Sun.
• It is the smallest of the eight main planets.
• It has the shortest orbital period (about 88 Earth days).
• It has no atmosphere and no moon, with extreme temperatures (very hot by day, very cold by night).

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(a) Sketch map of Africa showing the named rivers

(b) Characteristics of African rivers

1. Most African rivers have rapids, cataracts and waterfalls, especially where they cross plateaux and escarpments.
2. Many rivers show seasonal fluctuation in volume: they have more water and may flood during the rainy season, but their volume falls greatly in the dry season.
3. Many African rivers are shallow and fast-flowing, and their courses are often interrupted by rapids and falls; this limits navigation.
4. They carry much silt, mud and other debris, particularly in the rainy season, and may deposit this material to form flood plains and deltas.

(c) Uses of African rivers

1. They provide water for domestic use, irrigation and industries.
2. They are used for the generation of hydro-electric power at dams, rapids and waterfalls.
3. They support fishing, transport and tourism, and their alluvial deposits provide fertile soils for farming.

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(a) Map work

As shown on the outline map above, the following features are correctly located and named:

• Lake Kainji, in the north-western part of Nigeria, on the River Niger around Niger and Kebbi States.
• An area of extinct volcanoes on the Jos Plateau in north-central Nigeria.
• The Udi Hills, west of Enugu in south-eastern Nigeria.
• The River Hadeija, in north-eastern Nigeria, flowing through the Kano-Jigawa area towards the Hadejia-Nguru wetlands.

(b) Problems of development in the Eastern Borderland

Any four of the following are acceptable:

• Rugged and mountainous relief: The hilly terrain makes settlement, farming, road construction and communication difficult and expensive.
• Poor transport network and inaccessibility: Many settlements are remote, while roads may be poor, narrow or difficult to maintain, especially during the rainy season.
• Soil erosion: Heavy rainfall on steep slopes encourages sheet and gully erosion, leading to loss of fertile topsoil and destruction of farmland, roads and houses.
• Low soil fertility: Continuous cultivation, leaching and erosion reduce soil nutrients and lower agricultural output.
• Inadequate water supply: Some communities lack reliable potable water, particularly in areas where rivers are seasonal or groundwater is difficult to obtain.
• Flooding of lowland areas: Low-lying valleys may be flooded, damaging crops, settlements and transport routes.
• Rural-urban migration: Young and able-bodied people move to towns in search of employment, leaving fewer workers for rural development.
• Environmental degradation: Deforestation, overgrazing and unsuitable farming practices may worsen erosion and reduce land productivity.
• Scanty rainfall or drought in some northern sections: This limits crop production and causes shortage of pasture and water.

(c) Solutions to the problems

• Control erosion and improve soil fertility: Farmers should practise terracing or contour/strip farming on slopes, plant trees, and apply manure or fertilisers to restore soil nutrients and reduce soil loss.
• Improve accessibility: Government should construct and maintain all-season roads, bridges and drainage systems to link remote borderland settlements with markets and service centres.

Other acceptable measures include providing irrigation and reliable clean water supplies, establishing cattle ranches, promoting cooperative farming, reafforestation, channelising flood-prone water courses, and providing rural amenities to reduce rural-urban migration.

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(a) Reducing the map to a scale of 1:300,000

The original extract is drawn to a scale of \(1:100{,}000\) and measures 37.5 cm long by 36.6 cm broad. To redraw the outline at \(1:300{,}000\) every distance must be reduced to one-third, because the new denominator is three times larger:

\[ \text{New length} = \frac{37.5}{3} = 12.5\ \text{cm}, \qquad \text{New breadth} = \frac{36.6}{3} = 12.2\ \text{cm}. \]

The representative fraction of the reduced outline is therefore

\[ 1:100{,}000 \times 3 = 1:300{,}000. \]

The outline is drawn as a rectangle 12.5 cm long by 12.2 cm wide. On it the four required features are marked: (i) the low, flat land bordering the river channel is outlined and shaded as the area liable to flooding; (ii) the full course of River Rafin Bela is drawn from its source to its mouth with an arrowhead pointing downstream to show the direction of flow; (iii) the settlements of TILLI and ZOGIRMA are each shown by a small circle and named; and (iv) the 800 ft contour enclosing ZANUA HILL is drawn and the ground above it shaded completely.

(b) Four distinct drainage features on the map

1. Meanders - pronounced looping bends along the course of River Rafin Bela.
2. Watersheds - the high ground (including Zanua Hill) separating one drainage basin from the next.
3. Floodable (flood) plains - the wide, flat, low-lying land bordering the river channel.
4. Braiding - the division of the river into several interlacing channels around bars of deposited sediment.

River valleys and a dendritic (tree-like) drainage pattern are also clearly present on the extract.

(c) Six features along the minor road from Rafin Tsaka to Nageda

Human features:

1. Settlements (small nucleated villages along the route).
2. Bench marks (survey height points beside the road).
3. Areas of scattered cultivation (farm plots).

Physical features:

4. Scrub vegetation.
5. An open plain (flat lowland).
6. A hill and the adjoining river valley.

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(a) Transportation

Transportation is the movement of people, goods and services from one place to another using various means such as roads, railways, waterways, pipelines and air.

(b) Four advantages of air transportation

• It is the fastest means of transport, ideal for long distances.
• It can reach remote and difficult areas (mountains, deserts, islands) not served by roads or rail.
• It is not restricted by physical barriers on the ground such as rivers, hills or forests.
• It is suitable for carrying perishable, urgent and valuable goods and for emergency/relief services.

(c) Five contributions of transportation to economic development

• Promotes trade and commerce by moving goods from areas of production to markets and consumers.
• Opens up remote areas for farming, mining and settlement, aiding regional development.
• Creates employment for drivers, pilots, mechanics, loaders and transport workers.
• Aids industrialisation by moving raw materials to factories and finished goods to markets.
• Encourages tourism and links, generating revenue, and speeds the movement of labour and information, boosting overall growth.

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(a) Definition of flooding

Flooding is the overflowing of water beyond its normal channel so that it covers land which is usually dry. It occurs when the volume of water in a river, lake or coastal area exceeds the capacity of its channel or basin and spills onto the surrounding land (the flood plain).

(b) Causes of flooding

• Heavy and prolonged rainfall that supplies more water than the river channel can hold.
• Poor or blocked drainage, for example gutters and channels clogged with refuse.
• Overflowing of rivers and release of water from dams/reservoirs.
• Deforestation and removal of vegetation, which increases surface run-off.
• Building on flood plains and water channels, and rising sea level/storm surges along coasts.

(c) Effects of flooding

• Loss of lives and outbreak of water-borne diseases such as cholera.
• Destruction of property, houses, roads, bridges and other infrastructure.
• Destruction of farmlands and crops, leading to food shortage and hunger.
• Displacement of people (homelessness) and disruption of movement and business.
• Some deposition of fertile silt on flood plains (a positive effect).

(d) Solutions to flooding

• Construct and maintain good drainage channels, dams and embankments.
• Clear blocked drains and stop dumping of refuse in channels.
• Afforestation and protection of vegetation to reduce run-off.
• Prohibit building on flood plains and enforce proper physical planning.
• Public education and an early-warning system for heavy rains.

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(a) Outline map of Africa

The sketch map below shows an outline of Africa with the three required features clearly marked and named: the two belts that receive rainfall in winter (Mediterranean north coast and the south-western Cape), the dominant maritime tropical (mT) South-West Monsoon air mass drawn northwards across the Equator in July, and the northernmost July position of the Inter-Tropical Convergence Zone (ITCZ) over the Sahel.

Key to the map

• (i) Winter-rainfall areas (shaded): the Mediterranean coastlands of the extreme north (Atlas region of Morocco, Algeria, Tunisia) and the south-western Cape of South Africa. Both have a Mediterranean climate with hot, dry summers and mild, wet winters.
• (ii) Dominant air mass in July: the moist maritime tropical (mT) South-West Monsoon (equatorial maritime air) is drawn from the South Atlantic north-eastwards across the Equator into West and Central Africa, bringing the summer rains. The hot, dry continental tropical (cT) air dominates the Sahara to the north of the ITCZ.
• (iii) Position of the ITCZ in July: it lies in its northernmost position, well north of the Equator over the Sahel and southern Sahara (about 20°N).

(b) Effects of altitude on the climate of Africa

Altitude (height above sea level) strongly modifies the climate that latitude alone would produce, so that even places on the Equator can be cool. Its main effects are:

1. Temperature falls with height. Temperature decreases at an average rate of about \(6.5^{\circ}\text{C}\) for every \(1000\ \text{m}\) of ascent (the environmental lapse rate). Highland areas such as the Ethiopian Highlands, the Jos Plateau and the Kenya Highlands are therefore markedly cooler than the surrounding lowlands even though they lie near the Equator.
2. Cooler, temperate-like highland climates. Because of this cooling, equatorial highlands enjoy a pleasant, temperate-type climate that has attracted dense settlement and farming (for example the Kenya Highlands and the Jos Plateau).
3. Snow and ice on high peaks. The temperature drop is so great on the highest mountains that Kilimanjaro and Mount Kenya carry permanent snow and ice caps despite standing almost on the Equator.
4. Thinner air causes rapid heat loss. At high altitude the air is thin and contains less dust and water vapour, so it holds little heat and allows the ground's heat to escape (radiate) rapidly, especially at night. This gives large diurnal temperature ranges and cool nights on plateaux such as Jos.
5. Relief (orographic) rainfall. Highlands force moist air to rise, cool and condense, giving heavy relief rainfall on the windward slopes, while the leeward slopes lie in a dry rain-shadow with scanty rainfall.
6. Illustrative comparison. Nairobi and Mombasa lie on almost the same latitude, yet Nairobi, standing high on the plateau at about \(1675\ \text{m}\), has a much lower mean annual temperature than the coastal city of Mombasa near sea level. Using the lapse rate, the altitude difference alone accounts for a cooling of roughly \(\frac{1675}{1000}\times 6.5 \approx 10.9^{\circ}\text{C}\), confirming that altitude, not latitude, explains the contrast.

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(a) Definition of soil

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

(b) Characteristics of soil types

(i) Sandy soil

• Made of large, coarse particles with wide air spaces.
• Well drained and well aerated, but dries out quickly and holds little water.
• Light, loose and easy to till, but generally low in humus and nutrients (infertile).

(ii) Clay

• Made of very fine, tiny particles packed closely with little air space.
• Poorly drained and poorly aerated; it holds much water and becomes waterlogged.
• Heavy and sticky when wet, hard and cracked when dry, and difficult to cultivate.

(c) Four ways in which soil is important

• It supports plant growth by supplying nutrients, water and anchorage for roots.
• It is the basis of agriculture (crop farming) and grazing, supporting food production.
• It provides a habitat for soil organisms such as earthworms and bacteria.
• It supplies raw materials (clay for pottery/bricks, laterite for building) and helps store and filter water.

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(a) Five reasons why my country (Nigeria) has more trading partners outside Africa

• Similar products within Africa: most African countries produce the same primary goods (cash crops, minerals), so they have little to exchange with one another.
• Demand for manufactured goods: Nigeria imports machinery, vehicles, and technology which are produced mainly in Europe, America and Asia, not in Africa.
• Colonial ties and established links: long-standing trade relations built during the colonial era orient trade toward former colonial powers overseas.
• Ready market for raw materials/oil: industrialised countries outside Africa provide a large market for Nigeria's crude oil and raw materials.
• Poor intra-African transport and communication: weak road, rail and shipping links between African countries make trade with them difficult and costly.

Other reasons: differences in currency and trade barriers within Africa, and the higher purchasing power of countries outside Africa.

(b) Five ways trade between my country and other African countries could be improved

• Improve transport links (roads, railways, shipping and air routes) connecting African countries.
• Remove or reduce trade barriers such as high tariffs and border restrictions, and strengthen bodies like ECOWAS and the AfCFTA.
• Diversify production so that countries produce different goods that can be exchanged.
• Introduce a common currency or better currency-exchange arrangements to ease payment.
• Promote regional cooperation, joint industries and common markets, and improve communication and information about available goods.

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(a) Four advantages of concentrating industries in urban areas

• Availability of labour: large urban population supplies both skilled and unskilled workers.
• Good infrastructure: ready supply of electricity, water, roads, railways and ports serves the industries.
• Large market: the dense urban population and high purchasing power provide a ready market for goods.
• Availability of capital and services: banks, insurance and other financial and repair services are concentrated in towns, and firms benefit from linkages with one another (economies of agglomeration).

(b) Three disadvantages of concentrating industries in urban areas

• Pollution of air, water and land, and noise, harming health.
• Overcrowding, traffic congestion and pressure on housing and services (slums, high rents).
• Regional imbalance: rural areas are neglected and their people migrate to the towns; land and labour costs also rise.

(c) Three factors for the dominance of light industries in developing countries

• Low capital requirement: light industries (food processing, textiles, soap) need little capital, which suits countries short of investment funds.
• Use of local raw materials and simple technology: they process locally available agricultural raw materials and do not need advanced machinery or highly skilled labour.
• Ready local market and small scale: they produce consumer goods for the immediate local population and can operate on a small scale, matching low demand and limited power/energy supply.

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(a) Representing the statistics with proportional circles

In a proportional circle map the area of each circle is drawn in proportion to the quantity it represents. Because the area of a circle is proportional to the square of its radius (\(A = \pi r^2\)), the radius of each circle must be made proportional to the square root of the value, i.e. \(r \propto \sqrt{V}\). This prevents the larger circles from being exaggerated.

Step 1: Find the square root of each value.

City	Rail passenger traffic	\(\sqrt{V}\)	Radius (cm)*
Ibadan	5,000,000	2236.1	2.24
Enugu	3,000,000	1732.1	1.73
Maiduguri	2,500,000	1581.1	1.58
Port Harcourt	1,500,000	1224.7	1.22
Minna	1,000,000	1000.0	1.00

Step 2: Choose a radius scale. Let the smallest city (Minna, \(\sqrt{V}=1000\)) be drawn with a radius of 1.0 cm. The scale factor is therefore \[k = \frac{1.0\text{ cm}}{1000} = 0.001\ \text{cm per unit }\sqrt{V}.\] Multiplying every \(\sqrt{V}\) by \(k\) gives the radii in the last column above.

Step 3: Draw the circles. On the map of Nigeria, at the location of each city, draw a circle with the radius calculated above using a pair of compasses. Draw the smallest circle first and the largest last. Add a title, a key that shows a specimen circle with its value (e.g. a 1.0 cm circle = 1,000,000 passengers), and label each circle with the city name.

(b) Two advantages of representing data with proportional symbols

1. They show the actual geographical location of each value on the map, so the reader sees both the quantity and where it occurs at the same time.
2. They give an immediate visual comparison of magnitude, since the eye can quickly rank places by the size of the symbol without reading the figures.

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(a)(i) Formation of erosional plains

Erosional (denudation) plains are formed by the long-continued wearing down of a former highland by agents of denudation. Rivers, ice, wind and weathering slowly strip away the raised land over a very long period until the surface is reduced almost to a low, gently undulating plain (a peneplain). Continuous weathering, erosion and transport of the loosened material lowers the land close to base level, leaving occasional resistant remnants (monadnocks) standing above the plain.

(a)(ii) Formation of a dissected plateau

A dissected plateau is formed when an upland or plateau is cut into (dissected) by rivers. After uplift, active rivers flowing across the plateau erode deep, steep-sided valleys and gorges into it. Continued vertical (down-cutting) erosion by many streams divides the once continuous upland surface into separate blocks, ridges, spurs and flat-topped hills, giving a rugged, broken plateau surface.

(b) Advantages and disadvantages of plains

Advantages

• The flat, gentle land encourages agriculture, since it is easy to cultivate and often has deep, fertile alluvial soils.
• They favour settlement and construction of roads, railways and towns because building is easy and cheap.

Disadvantages

• Low, flat plains near rivers are liable to flooding and may become waterlogged/swampy.
• They may suffer poor drainage and, in dry areas, can be exposed and monotonous, encouraging soil erosion by wind or sheet wash.

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(a) Outline map of Nigeria showing oil palm and cattle rearing areas

On the outline map below, the oil palm production area is shaded in the south-east (the Niger Delta / South-Eastern belt), the cattle rearing area is shaded in the far north (the Sudan / Sahel savanna belt), and the required towns are marked with dots and named.

• (i) Oil palm production area: the South-East / Niger Delta belt (Imo, Abia, Akwa Ibom and Rivers area), shaded green.
• (ii) Cattle rearing area: the far northern Sudan / Sahel savanna belt (Sokoto, Kano, Katsina and Borno area), shaded brown.
• (iii) One town in the oil palm area: Aba.
• (iv) Two towns in the cattle rearing area: Kano and Sokoto.

(b) Three factors that favour cattle rearing in the northern area

1. Abundant pasture and savanna vegetation: the extensive grassland of the Sudan and Sahel savanna provides plentiful natural grass for the cattle to graze on.
2. Absence of the tsetse fly: the dry northern climate is largely free of the tsetse fly, so the cattle are not attacked by trypanosomiasis (sleeping sickness).
3. Favourable climate and wide grazing land: the moderate rainfall of about 50 - 125 cm per year with low relative humidity encourages grass growth, while the vast, flat open plains allow the herds to move and graze freely.

(c) Three ways in which cattle rearing is of importance to Nigeria

1. Source of food: cattle supply meat, milk and other dairy products, providing protein for the population.
2. Source of income and employment: the rearing, sale and processing of cattle provide a livelihood for herders, traders and butchers, and yield revenue to government through cattle tax (Jangali).
3. Source of raw materials: hides and skins from cattle are used in the leather and allied industries, while the dung provides organic manure for farming.

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Tropical Grasslands (Savanna)

(a) Location

Tropical grasslands lie between the tropical rainforest and the hot deserts, roughly between latitudes 5 degrees and 15-20 degrees north and south of the Equator. Major areas include the savanna of West and East Africa (the Sudan and Guinea savanna, the Serengeti), the llanos of the Orinoco basin and campos of Brazil in South America, and parts of northern Australia and the Deccan of India.

(b) Climatic factors affecting distribution

• Alternating wet and dry seasons: a distinct rainy season (high sun) and a long dry season (low sun) which prevents dense forest and favours grasses.
• Moderate, seasonal rainfall of about 500-1,000 mm concentrated in the wet season.
• High temperatures all year (about 21-32 degrees C), being within the tropics.
• Movement of the ITCZ and the influence of wet maritime and dry continental (Harmattan/Trade) winds, which control the length of the seasons.

(c) Vegetation characteristics

• Dominated by tall grasses (elephant grass) that grow lush in the wet season and turn brown and dry, sometimes burning, in the dry season.
• Scattered, drought-resistant trees such as the baobab and acacia, which are deciduous, have small leaves, thick bark and flat/umbrella crowns.
• Trees are more numerous and taller near the forest margin and become fewer and shorter (giving way to thorn scrub) towards the desert margin.
• Vegetation is xerophytic (adapted to drought) with long roots and fire-resistant features.

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(a) Outline map of Nigeria showing areas of population density

(b) Three factors responsible for the dense population of the South-East

1. Fertile soils and favourable climate: the region has fertile land and a reliable rainfall that support intensive farming and a dependable food supply, so it can carry a large number of people.
2. Commercial and industrial activity: busy trading and manufacturing centres such as Onitsha, Aba and Nnewi offer wide employment and business opportunities that attract and hold people.
3. Good social amenities and long settlement: the availability of schools, hospitals, water, electricity and a dense network of roads, together with the long history of settled Igbo communities, has encouraged a heavy concentration of people.

(c) Three problems of the dense population of the South-East

1. Overcrowding and housing shortage: too many people compete for limited housing, leading to high rents, congestion and the growth of slums with poor sanitation.
2. Pressure on land and social amenities: farmland becomes fragmented and scarce, and schools, hospitals, water and other services are overstretched, while unemployment rises as jobs cannot match the number of people.
3. Environmental and social strains: heavy population brings traffic congestion, pollution, poor waste disposal, soil erosion from over-use of land, and a higher crime rate.