JAMB UTME - Geography - 1997

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Lines joining places of equal sunshine hours on a map are called isohels. These lines show areas with the same amount of sunshine hours in a given period, usually per day or year. The term "iso" means equal, while "helio" refers to the sun. Isohels can be used to determine the distribution of solar radiation in a particular region, which can affect various processes such as temperature, plant growth, and weather patterns.

Détails de la réponse

Détails de la réponse

The main reason for the formation of the Economic Community of West African States (ECOWAS) was to expand the market for the products of member states. ECOWAS was formed to promote regional economic cooperation among West African countries by removing trade barriers, harmonizing policies, and creating a free trade area. It was believed that by working together and creating a larger market, member states could increase their bargaining power and better compete in the global market.

Détails de la réponse

Détails de la réponse

The low level mechanized agriculture in West Africa is best explained by the predominance of small farm holdings. In West Africa, small-scale agriculture dominates due to the low income levels of most farmers and the lack of investment capital. As a result, farmers rely on manual labor and basic tools to cultivate their crops. This leads to low levels of mechanization in agriculture. Additionally, the small farm holdings limit the ability of farmers to invest in expensive machinery, which is often not suitable for small plots of land. Therefore, the low level of mechanization is mainly attributed to the predominance of small farm holdings in West Africa.

Détails de la réponse

The global decline in the use of coal as a source of energy is due to the availability of cheaper and cleaner energy sources. Coal has traditionally been a primary source of energy for many countries, but in recent years, the development of renewable energy sources like wind and solar, as well as the increased use of natural gas, has made coal less economically competitive. Additionally, the negative environmental impacts associated with coal, such as air pollution and greenhouse gas emissions, have made it less attractive as a source of energy. As a result, many countries are investing in cleaner and more sustainable energy sources, which has led to a decline in the use of coal.

Détails de la réponse

The warm ocean current which washes the southeastern coast of Africa is called the Agulhas current. It flows southwards along the eastern coast of South Africa, from the Mozambique Channel towards the southern tip of the African continent. The Agulhas current is a strong and narrow current that carries warm and salty water from the tropics towards the colder waters of the southern Atlantic and Indian Oceans. It is an important current that plays a significant role in the climate and marine ecosystems of the region, influencing the weather patterns and providing a habitat for a diverse range of marine life.

Détails de la réponse

Iron deposits are found in economic quantities in Liberia, Sierra Leone and Guinea. These countries are part of the West African Craton, a geological formation that is rich in mineral resources including iron ore. Iron ore is an important raw material for the production of steel, which is used in construction, manufacturing, and other industries. The deposits in these countries are among the largest in the world, and have played an important role in their economies.

Détails de la réponse

The drainage pattern illustrated in the diagram is radial. This is because the streams flow outward from a central high point, such as a mountain or volcano, and radiate in different directions. This type of pattern is often found in areas with a prominent central peak or dome-shaped landforms, where the streams are forced to flow in different directions away from the high point.

Détails de la réponse

Détails de la réponse

The leading rubber producing areas of the world are Malaysia, Indonesia and Sri Lanka. These countries have favorable climate and soil conditions for the growth of rubber trees and have invested heavily in the rubber industry. They have well-established infrastructure for the cultivation, processing, and export of rubber. The rubber produced in these countries is of high quality and is in high demand globally for various industrial and consumer products.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

The cheapest means of transport for long distance travel is by **water**. Water transport is generally more cost-effective than other modes of transport for long distances, especially for bulky or heavy goods. Shipping lines can carry large quantities of cargo at once, resulting in lower costs per unit compared to air or road transport. Additionally, water transport has a lower fuel consumption per tonne-kilometre than land transport, which also helps to reduce costs.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

The four ways in which a river transports its load are: 1. Traction - this is when large particles are rolled along the river bed by the force of the water. 2. Saltation - this is when small particles bounce along the river bed in a hopping motion. 3. Suspension - this is when small particles are carried along in the water, making the water appear muddy or cloudy. 4. Solution - this is when minerals are dissolved in the water and are transported in the solution. Therefore, the correct option is "saltation, solution, suspension and traction".

Détails de la réponse

Détails de la réponse

The angle of inclination best explains the generally low insolation in the high latitudes. The angle of inclination refers to the angle at which the sun's rays hit the Earth's surface. In the high latitudes, the angle of inclination is very low, meaning that the sun's rays are spread out over a larger area, resulting in lower levels of insolation. This is because the curvature of the Earth causes the angle of incidence to be shallower at high latitudes compared to the lower latitudes, where the sun is directly overhead at noon. Therefore, the low angle of inclination results in lower solar radiation and energy received per unit area of land in the high latitudes.

Détails de la réponse

Détails de la réponse

The most ideal statistical mapping technique for showing population migration is the flow diagram. A flow diagram displays the movement of people from one location to another over a period of time using arrows or lines of varying thickness to represent the volume of migration. This technique is particularly effective for illustrating the direction, magnitude, and patterns of population movement. Choropleth maps can show population density, while dot maps can show the location of individual events or phenomena. Isopleth maps are more commonly used to display spatial variations of continuous data, such as elevation or temperature. However, flow diagrams are best suited for representing population migration as they allow for easy identification of both the origin and destination of the migration flows.

Détails de la réponse

Nutrients lost by trees in leaf-fall can be re-used by the trees because nutrients circulate in the ecosystem. When trees shed their leaves, the nutrients in the leaves are returned to the soil. The nutrients are then taken up by the roots of the trees and used to grow new leaves. This process is part of the natural nutrient cycle in ecosystems, where nutrients are constantly being recycled and re-used by different organisms. Therefore, trees do not need to store nutrients, as they can take them up from the soil as needed.

Détails de la réponse

The lake in Africa that emitted toxic gas and caused the death of a large number of people in 1986 is Lake Nyos. On August 21, 1986, carbon dioxide gas trapped at the bottom of the lake suddenly erupted, causing a massive cloud of carbon dioxide to spread across the surrounding area. The gas cloud suffocated approximately 1,700 people and 3,500 livestock in nearby villages, and caused widespread panic in the region. The disaster led to renewed scientific interest in the study of limnology (the study of lakes) and the hazards associated with volcanic lakes in particular.

Détails de la réponse

The shaded area labelled Z on the map indicates the part of Nigeria that suffers most from drought and desertification. Drought is a prolonged period of below-average rainfall, which can lead to water shortages and crop failure. Desertification, on the other hand, is a process of land degradation that occurs in arid, semi-arid and dry sub-humid regions due to various factors, including drought, deforestation, and overgrazing. The combination of drought and desertification can lead to food and water shortages, loss of vegetation, and soil erosion. These conditions can have severe impacts on the environment, economy, and social well-being of the affected regions.

Détails de la réponse

Détails de la réponse

Détails de la réponse

The serious environmental hazard which may result from the destruction of the ozone layer is an increase in atmospheric temperature. The ozone layer is a protective layer of gas in the Earth's atmosphere that absorbs most of the sun's ultraviolet (UV) radiation. If this layer is destroyed, more UV radiation will enter the atmosphere, leading to an increase in temperature. This can cause a wide range of problems, such as changes in climate patterns, sea level rise, and loss of biodiversity.

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

Détails de la réponse

The most important environmental resource that sustains natural processes in an ecosystem is water. Water is necessary for the survival of plants and animals, and it plays a critical role in nutrient cycling, temperature regulation, and the maintenance of ecological balance. Without water, ecosystems would collapse, and life on earth would be impossible. Water is essential to all living things and serves as a critical resource for human societies as well, supporting agricultural production, industrial processes, and human consumption.

Détails de la réponse

The area served by a given city is called its sphere of influence. This refers to the geographical area around a city where the city has significant economic, political, and social influence. It includes the city's immediate suburbs as well as more distant areas that are economically and socially connected to the city. The sphere of influence can vary depending on the size and importance of the city, as well as its location and accessibility.

Détails de la réponse

Détails de la réponse

Aluminum smelting is a process that requires a lot of electricity to extract aluminum from its raw material, bauxite. Therefore, aluminum smelters are usually located close to sources of abundant electricity. In addition to electricity, aluminum smelters also require raw materials, such as bauxite and alumina, to produce aluminum. However, the proximity of these raw materials is not as critical as the availability of electricity. Coking coal is not directly required for aluminum smelting, but it is used in the production of electricity in some cases. Cheap labor may also be a consideration, but it is not a main factor in the location of aluminum smelters.

Détails de la réponse

Détails de la réponse

Détails de la réponse

An entrepôt is a trading post where merchandise can be imported and exported without paying import duties. Therefore, the correct answer to this question depends on whether the city listed has historically functioned as an entrepôt. Out of the options provided, Rotterdam is the most commonly recognized city as an entrepôt, as it has served as a major trading port since the 17th century, linking Europe to the rest of the world. New York and London have also functioned as important trading hubs, but are not typically referred to as entrepôts. Sydney, while an important city, is not historically known for its role as an entrepôt.

Détails de la réponse

Détails de la réponse

Détails de la réponse