WAEC SSCE - Geography - 1994

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A state of inter-dependence within the ecosystem is best achieved when the components are undisturbed. This is because every living and non-living component of an ecosystem plays a vital role in sustaining life. The components of an ecosystem depend on each other for survival and function as a unit. Any disturbance to one component can lead to a ripple effect on the others, leading to imbalances and possible collapse of the ecosystem. Thus, maintaining the natural balance and inter-dependence within an ecosystem is crucial for its stability and sustainability.

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When the sun is directly overhead at the tropic of Capricorn on 22nd December, the Northern Hemisphere experiences its winter solstice. The winter solstice is the day with the shortest period of daylight and the longest night of the year. This occurs because the North Pole is tilted furthest away from the sun on this day. As a result, the sunlight falls at a very oblique angle on the Northern Hemisphere causing less energy to be received in the region, leading to a decrease in temperature.

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The Aswan Dam in Egypt provides both irrigation water and hydro-electricity. The dam is located on the Nile River and was completed in 1970. It is one of the largest dams in the world, and its reservoir, Lake Nasser, provides water for irrigation to over 3 million acres of land, as well as hydroelectric power for much of Egypt's population. The other dams listed also provide hydro-electricity, but their main purpose is either irrigation (Gezira) or flood control (Kainji, Cabora Bassa, Akosombo).

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Tsetsefly infestation least influences population density in Nigeria. Tsetse flies are known to transmit diseases that affect both humans and animals, and as such, their presence has a negative impact on human settlements in affected areas. Areas with high tsetse fly infestation are often avoided by settlers, thereby limiting population density. On the other hand, the other options listed in the question, such as mining, fertile agricultural land, thick forest vegetation, and industrialization, can have both positive and negative effects on population density in Nigeria.

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The size of the individual grains of soil is referred to as the texture. Texture is one of the most important physical properties of soil, and it refers to the size distribution of the mineral particles that make up the soil. Soil texture can be classified as either sand, silt, or clay, depending on the size of the mineral particles. Sand particles are the largest, followed by silt and then clay, with clay particles being the smallest. The texture of the soil affects the ability of the soil to retain water and nutrients, as well as its workability for agricultural purposes.

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A large expanse of low, level land, formed due to an uplift of part of the sea floor bordering a continent is called a coastal plain. Coastal plains are characterized by a broad strip of low-lying land adjacent to the coast, often consisting of sand and sediment deposited by rivers and ocean currents. Coastal plains are common features along the edges of continents and can extend for hundreds of kilometers inland. They are important for human settlement and economic activities such as agriculture, fishing, and tourism.

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The effect of rural-urban migration on the source region is rural depopulation. When people migrate from rural areas to urban centers in search of better job opportunities, healthcare facilities, education, and improved living standards, the rural areas experience a decline in population. This can have a negative impact on the rural economy as there may be fewer people to work on farms and other agricultural activities, leading to a decrease in agricultural production. Rural depopulation may also result in a decline in social amenities, such as schools and health facilities, as well as a decrease in the provision of basic infrastructure such as roads and electricity. This can have a ripple effect on the standard of living of those who remain in rural areas.

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Mountains formed as a result of compressional forces in the earth's crust are called fold mountains. Fold mountains are formed when two tectonic plates collide and push up layers of rock into folds, resulting in a series of peaks and valleys. The compression forces cause the rocks to deform and buckle, leading to the creation of folds. The Himalayas and the Alps are examples of fold mountains.

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The best example of a non-renewable resource among the given options is minerals. Minerals are geological materials that exist in a fixed amount in the Earth's crust, and they are formed over millions of years through geological processes. Once these minerals are extracted and used, they cannot be replaced or replenished in a short time. Hence, minerals are considered as non-renewable resources, unlike water, air, and vegetation which can be renewed through natural processes such as the water cycle, photosynthesis, and atmospheric circulation, respectively. Therefore, of the given options, minerals are the best example of a non-renewable resource.

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Greenheart, mahogany, and ebony are commonly found in the natural vegetation belt known as the Selvas. The Selvas is a tropical rainforest vegetation belt that is characterized by dense forests with tall trees, high rainfall, and high humidity. The region is also known for its high biodiversity with a wide variety of flora and fauna. The Selvas is found in parts of South America, Central America, and West Africa.

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The winds whose direction is reversed from one season to another are called monsoons. Monsoons are characterized by seasonal reversal of wind direction, which are caused by differential heating and cooling of land and water surfaces. During summer, the land gets heated more than the ocean, causing a low-pressure zone over the land and high-pressure zone over the ocean, which leads to moisture-laden winds blowing from the ocean towards the land. In winter, the opposite occurs due to the reversal of the pressure gradient, causing the dry winds to blow from the land towards the ocean. This phenomenon is most commonly observed in South and Southeast Asia.

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Sand is the most permeable soil type. Permeability refers to the soil's ability to allow water to pass through it. Sand has larger particles with wider spaces between them, which allows water to flow more easily through the soil. This makes it easier for plant roots to access water and nutrients in the soil. In contrast, clay soils have smaller particles with less space between them, which makes it more difficult for water to pass through. Loam is a combination of sand, silt, and clay, and its permeability depends on the proportions of these components. Laterite soils are typically rich in iron and aluminum, which makes them hard and impermeable. Peat soils are composed of partially decayed organic matter and tend to be waterlogged, which reduces their permeability.

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Temperate grasslands are commonly known as steppes. Steppes are large areas of flat grassland found in temperate climates, which are characterized by cold winters and hot summers. They are mostly found in the interior of continents and are also known as prairies, pampas, or savannas depending on the region of the world where they occur.

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Wind action is more predominant in arid regions than in humid regions because of the loose surface materials and the absence of vegetation cover in arid regions. In arid regions, there is little or no vegetation to hold the soil in place, and the loose surface materials make it easier for wind to move the soil particles around. In contrast, in humid regions, the soil is held in place by vegetation cover, and the soil is generally denser, making it harder for wind to move the soil particles. Additionally, the other options are not correct explanations for why wind action is more predominant in arid regions than in humid regions.

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Cameroon is not a member of the Economic Community of West African States (ECOWAS). ECOWAS is a regional economic union made up of fifteen West African countries. Cameroon, while it shares some borders with ECOWAS member countries and has strong economic ties with the region, is not considered part of West Africa and therefore is not a member of the organization.

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Koppen's classification of climate is based on two primary factors: precipitation and temperature. These factors are used to classify the world's climates into five major groups, which are further subdivided into smaller groups based on other factors such as seasonality, humidity, and wind patterns. The classification system takes into account the amount and distribution of rainfall throughout the year and the average temperature of the warmest and coolest months. By combining these two factors, Koppen's classification provides a comprehensive system for understanding the major climatic regions of the world.

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The description given refers to sedimentary rocks. Sedimentary rocks are formed by the accumulation of sediments over time, which may be derived from the erosion of pre-existing rocks or the remains of dead organisms. These sediments are deposited in layers and then compacted and cemented together to form rock. Examples of sedimentary rocks include sandstone, limestone, and shale.

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Tropical Asia has the highest population concentration. This is because the region has a very high population density due to the presence of large countries with large populations such as China and India, as well as high urbanization rates. Additionally, the region has a relatively small land area compared to its population, which makes it one of the most densely populated regions in the world.

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An aquifer is a type of rock layer that is permeable and can hold water. Water is able to flow through the small spaces and cracks within the rock, and this makes the aquifer an important source of groundwater. The permeability of the rock allows water to be stored within the aquifer, and this water can be accessed through wells for human use.

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Urbanization refers to the process of a significant increase in the proportion of the population of a country or region living in urban areas (cities or towns). It involves the growth of urban areas in terms of both population and physical size, as well as the expansion of urban land use into surrounding rural areas. This can be due to various factors such as industrialization, rural-urban migration, and natural population growth. Option A "growth of towns, especially in terms of human population and physical size" accurately describes urbanization.

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The bush fallowing system is an agricultural practice used in West Africa where farmers clear a plot of land, cultivate it for a few years, and then allow it to lay fallow for a period of time to regain its fertility before clearing and cultivating another plot. This system has several advantages, including allowing the land to regain its fertility during fallow, being very economical in the use of land, and reducing the need for the use of artificial fertilizers. However, one disadvantage of the bush fallowing system is that it could lead to soil erosion. Therefore, the correct answer to the question is option D: "could lead to soil erosion."

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Coal is associated with organically-formed sedimentary rocks. Coal forms from the accumulation and transformation of plant material over millions of years under heat and pressure. These organic materials include leaves, wood, bark, and other plant remains that are buried in sedimentary basins. As they are subjected to heat and pressure, they undergo chemical and physical changes that eventually transform them into coal. Therefore, coal is typically found in rocks such as shale, sandstone, and limestone that were formed from sediments deposited in swamps, lakes, and other wetland environments where plant material could accumulate.

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One characteristic that distinguishes urban settlements from rural settlements is that urban settlements are areas of secondary and tertiary activities. Urban settlements are usually characterized by a higher population density, larger size, and greater economic and social complexity compared to rural settlements. Urban areas are typically centers of commerce, industry, education, and government, and offer a wider range of employment opportunities and services, such as healthcare, transportation, and entertainment, compared to rural areas, which tend to focus more on primary activities such as agriculture, mining, and forestry.

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The equatorial diameter of the Earth is the distance from one point on the equator to the point diametrically opposite on the equator, passing through the center of the Earth. The correct answer is 12.760km.

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The development of hydro-electric power in Nigeria is least affected by the presence of high mountains. Hydro-electric power is generated by harnessing the potential energy of water stored in dams. The water is allowed to flow through turbines which drives generators to produce electricity. The height from which the water falls and the volume of water flow are the two main factors that determine the amount of electricity generated. High mountains are ideal for the construction of hydro-electric power stations because they provide a high head of water, which means that the water can fall from a greater height, thus producing more energy. However, the presence of high mountains is not an essential requirement for the development of hydro-electric power. Other factors such as a regular supply of water, availability of suitable sites for dams, and the rapid increase in demand for electricity are more critical to the development of hydro-electric power in Nigeria. Additionally, while the high cost of construction may be a limiting factor, it is not necessarily the least affected factor as it can significantly impact the viability of a hydro-electric power project.

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The best option that explains the drift of population from rural to the cities in Nigeria is that there are more job opportunities in the cities. This means that people migrate from rural areas to urban areas in search of jobs or better economic opportunities. The cities provide more employment opportunities in the manufacturing, service, and trade sectors. Many young people also move to cities in search of better education and training facilities. Other factors, such as access to better healthcare, social amenities, and improved standards of living, also attract people to the cities.

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All the options listed in the question are causes of mechanical weathering except rain action. Mechanical weathering involves the physical breakdown of rocks into smaller fragments without altering their chemical composition. Rain action or dissolution is a chemical weathering process that involves the breakdown of rocks through the chemical alteration of minerals. Temperature changes, alternate wetting and drying, frost action, and action of plants and animals are examples of mechanical weathering processes that occur due to physical forces such as expansion, contraction, and pressure.

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The best account for the decline in the importance of rail transport in Africa is high competition from road transport. Road transport has become a more popular mode of transportation in Africa due to the increasing number of vehicles on the roads and the flexibility it offers in terms of destination and speed. Unlike rail transport, road transport offers door-to-door delivery, which makes it more convenient for businesses and individuals. This has led to a decline in the use of railways for transporting goods and people, resulting in a decrease in the importance of rail transport in Africa.

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The best example of a non-renewable resource among the given options is "minerals". Minerals are natural resources that cannot be replaced or regenerated within a short time frame. They are finite and exhaustible. Once they are extracted and used, they are depleted and cannot be replenished easily. Some examples of non-renewable minerals include coal, oil, natural gas, and metals such as iron, copper, and gold. In contrast, renewable resources such as water, air, and vegetation can be replenished naturally and sustainably over time.

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When on-shore winds blow over cold ocean currents, the temperatures of adjacent coastlands are reduced because the temperature of the prevailing winds is influenced by the cold currents. The cold currents cool the overlying air, which in turn cools the onshore winds blowing over them. This results in a decrease in temperature along the coastlands. So, the correct option is "current influences the temperature of the prevailing winds."

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Desert encroachment refers to the gradual expansion of arid or desert areas into previously habitable lands due to human activities or climate change. The best way to control desert encroachment is to plant trees, which is known as afforestation. Trees help to stabilize soil, retain moisture, and prevent wind erosion, thus helping to maintain the fertility of the land. This can be achieved by planting trees in strategic locations or through reforestation programs. Erecting barriers, deforestation, overgrazing, and slopewise cultivation can have negative impacts on the environment and may exacerbate desert encroachment in the long run.

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One relative advantage of water transport over road transport is its suitability for bulky and heavy cargo. Water transport, such as shipping and barges, are capable of carrying large and heavy loads of goods that would be difficult or impossible to transport by road. Water transport can also be more cost-effective than road transport for long-distance transport of heavy goods. This makes water transport a popular choice for industries such as mining and agriculture, where large quantities of goods need to be transported over long distances.

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