WAEC SSCE - Geography - 2019

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Rift valleys are formed through a process called faulting. Faulting occurs when the Earth's crust cracks and breaks along two parallel faults, causing the land between the faults to sink and form a valley. This process can happen over a long period of time and can be caused by various geological factors, such as tectonic plate movements, volcanic activity, and changes in the Earth's crust. In simple terms, rift valleys are formed when the ground splits and sinks along two cracks, creating a valley between them. This splitting and sinking of the land is called faulting and is caused by various geological processes.

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Most industries in the West African sub-region are small-scale. Small-scale industries are those that produce goods or services on a small or localized scale, often using simple technologies and manual labor. In West Africa, many industries are small-scale because the region has a largely rural and informal economy, with many people working in agriculture and informal trade. Small-scale industries can include food processing, textiles, handicrafts, and construction materials. While there are some large-scale industries in the region, such as mining and oil production, these tend to be concentrated in specific areas and are often dominated by foreign companies. Small-scale industries can provide important opportunities for local employment and economic development in the region. They can also be more adaptable to local conditions and needs than large-scale industries.

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A drainage pattern that is represented by one of the options given is the Trellis pattern. A drainage pattern is a geological term that describes the layout of the network of channels that make up a river system. It is influenced by the underlying geology, topography, and climate of a region. There are several types of drainage patterns, including dendritic, trellis, radial, rectangular, and parallel patterns. The Trellis drainage pattern is characterized by a main river channel that is joined at nearly right angles by smaller tributaries. The pattern is usually formed in regions with folding or parallel folding of rock layers. The tributaries usually form in valleys between the ridges formed by the folds, and they flow into the main channel, which runs parallel to the ridges. The pattern resembles a garden trellis or net, with the main channel representing the vertical lines and the tributaries the horizontal lines. Therefore, the Trellis pattern is a type of drainage pattern characterized by smaller tributaries joining the main river channel at nearly right angles.

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Transportation does not necessarily help in the distribution of the human population. While transportation does facilitate the movement of people and commodities, promote national and international trade, and diffuse ideas and technology, it does not necessarily result in a more even distribution of the population. For example, transportation infrastructure can lead to urbanization and the concentration of people in certain areas, rather than spreading them out more evenly across a region. The location and availability of transportation options can also influence where people choose to live and work, leading to imbalances in population distribution. In simple terms, transportation helps in many ways to support economic development, but it does not always result in a more even distribution of the population.

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The predominant process of weathering in the desert region is physical weathering. Physical weathering is the breakdown of rocks into smaller pieces without changing their chemical composition. In the desert region, temperature changes and the movement of wind-blown sand and rock fragments can cause physical weathering. Over time, rocks in the desert are broken down into smaller pieces and eventually into sand, which can then be carried away by the wind. While chemical and biological weathering can also occur in the desert, physical weathering is the most common due to the unique environmental conditions in this region.

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The sum total of human resources available in a country is called its population. Population refers to the total number of people who live in a specific geographic area, such as a city, state, or country. It is usually measured by a census, which is a survey that counts every person in a given area. Population is an important measure of a country's human resources because it can provide insight into the size and demographics of the workforce, as well as the overall social and economic characteristics of the country. Therefore, the total number of people living in a country is called its population.

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Volcanoes are formed when magma, ash, and gas escape from a magma chamber and rise to the Earth's surface. There are several types of volcanic features that are formed by this process. A ventifact is not a volcanic feature. A ventifact is a geological feature that is formed by the erosive action of wind-blown sand on rocks. Over time, wind-blown sand can abrade rocks and create unusual shapes and formations. Therefore, the answer is: Ventifact. Ventifacts are not related to volcanic activity and are formed by the action of wind on rock surfaces, while calderas, geysers, and dykes are all volcanic features formed by the movement of magma and other volcanic material.

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The Greek System of climate classification is based on temperature, which is the main element used to classify different climates. This system divides climates into three main categories based on average temperature: the tropical, temperate, and polar climates. Within each of these categories, there are further subdivisions based on temperature and other factors such as rainfall, humidity, and pressure. For example, the Mediterranean climate is a subdivision of the temperate climate category and is characterized by mild, wet winters and hot, dry summers. Therefore, the element of climate used in the Greek System of climate classification is temperature. While other factors such as rainfall, humidity, and pressure are considered, they are not the primary factors used to classify climates in this system.

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A crescentic depositional feature found in desert mice is a Barchan dune. This type of dune is shaped like a crescent moon and has horns pointing downwind. Barchan dunes form in areas where there is a limited supply of sand, and wind blows predominantly from one direction. As sand is blown up the windward side of the dune, it accumulates and forms the crescentic shape. The wind then moves the sand over the crest and down the leeward slope, creating the horns. Barchan dunes can range in size from a few meters to several hundred meters, and are commonly found in desert regions around the world.

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The scale of a map tells us how much the size of the map feature on the paper corresponds to the actual size of that feature on the ground. In other words, it tells us how much the map has been reduced compared to the actual size of the area being mapped. In the first statement, "one centimeter on the map represents half a kilometer on the ground", it means that every 1 centimeter on the map represents a distance of 0.5 kilometers on the ground. In the second statement, "One centimeter on the map represents one kilometer on the ground", it means that every 1 centimeter on the map represents a distance of 1 kilometer on the ground. In the third statement, "One centimeter on the map represents five kilometers on the ground", it means that every 1 centimeter on the map represents a distance of 5 kilometers on the ground. In the fourth statement, "One centimeter on the map represents fifteen kilometers on the ground", it means that every 1 centimeter on the map represents a distance of 15 kilometers on the ground.

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The statistical method represented above is a flow chart. The flow chart is a graphical representation of the volume and direction of passenger traffic between IZABU town and its surrounding towns in the year 2001. Each line on the chart represents 1,500 persons who travelled between two towns, and the direction of the line indicates the direction of travel. The width of the line may indicate the relative volume of passengers who traveled between the two towns. Therefore, a flow chart is a type of diagram that shows the movement of objects or people between different locations or stages.

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The density of the earth's crust varies from 2.5 g/cm3 to 3.3 g/cm3. The Earth's crust is the outermost layer of the Earth, and is composed of various minerals and rocks. The density of the crust varies depending on its composition, with lighter minerals like quartz and feldspar having lower densities than heavier minerals like iron and magnesium. Overall, the average density of the Earth's crust is around 2.7 g/cm3, which is much lower than the densities of the Earth's mantle and core. It is important to note that the density of the crust can also vary locally depending on factors like the presence of mineral deposits or the formation of mountains and other geologic features.

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Igneous rocks are formed from the solidification of magma or lava. Depending on where the rock cools and solidifies, it can be classified as either extrusive or intrusive. Extrusive rocks are formed when lava from a volcanic eruption cools quickly on the surface of the earth, forming small crystals or no crystals at all. On the other hand, intrusive rocks are formed when magma cools slowly underground, allowing larger crystals to form. Out of the four examples of igneous rock, basalt is the only extrusive rock. Basalt is formed from the rapid cooling of lava on the surface of the earth, resulting in small or no crystals. Granite, gabbro, and diorite, on the other hand, are all intrusive rocks that formed from slow cooling of magma deep within the earth, resulting in larger crystals. Therefore, the correct answer is "Basalt".

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The rock that is not metamorphic is Shale. Metamorphic rocks are formed from pre-existing rocks that have undergone physical and chemical changes due to high pressure, heat, or both. The process of metamorphism can cause the minerals in the original rock to recrystallize and form new minerals, resulting in a change in texture and composition. Schist, quartzite, and slate are all examples of metamorphic rocks. Schist is formed from shale or mudstone that has undergone high pressure and heat, causing the minerals in the rock to recrystallize into thin, platy layers. Quartzite is formed from sandstone that has undergone a process of recrystallization, cementation, and metamorphism. Slate is formed from shale or mudstone that has undergone low-grade regional metamorphism. Shale, on the other hand, is a sedimentary rock that is formed from compacted mud or clay. It is not formed through the process of metamorphism and therefore cannot be classified as a metamorphic rock. Therefore, Shale is the rock that is not metamorphic.

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Banking, insurance, and teaching are examples of the tertiary industry. The tertiary industry refers to the service sector of an economy, which involves the provision of services to individuals and businesses. This industry includes activities such as banking, insurance, education, healthcare, hospitality, and professional services such as accounting, consulting, and legal services. In contrast, the primary industry refers to the sector of an economy that involves the extraction and production of natural resources, such as agriculture, forestry, fishing, and mining. The secondary industry refers to the sector of an economy that involves the manufacturing of goods, such as the production of cars, clothing, electronics, and other products. So, banking, insurance, and teaching are examples of the tertiary industry because they are service-based industries that provide services to individuals and businesses, rather than producing goods or extracting natural resources.

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The traffic between IZABU and Anikpu is more than the traffic between IZABU and Ugba by 1,500 people. To determine this, we can compare the length of the lines in the diagram. The line representing the traffic between IZABU and Anikpu is longer than the line representing the traffic between IZABU and Ugba, which means that more people are traveling between IZABU and Anikpu than between IZABU and Ugba. According to the scale, one line represents 1,500 people, so if the line between IZABU and Anikpu is 1 unit longer than the line between IZABU and Ugba, that means the difference in traffic is 1,500 people. In simple terms, the difference in traffic between IZABU and Anikpu compared to IZABU and Ugba is 1,500 people, as shown by the difference in the length of the lines in the diagram.

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The climatic type that has winter rain is the Mediterranean climate. The Mediterranean climate is characterized by mild, wet winters and hot, dry summers. This type of climate is found in coastal regions bordering the Mediterranean Sea, as well as in other regions with similar climates, such as California in the United States. The winter rains in Mediterranean climates are a result of the prevailing westerly winds, which bring moist air from the Atlantic Ocean. This moisture is then deposited as rain in the coastal regions with Mediterranean climates, providing a source of water during the typically dry summer months. The winter rain and the mild temperatures of the Mediterranean climate make it ideal for growing a wide variety of crops, including fruits, vegetables, and wine grapes.

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To determine the number of passengers who travelled between IZABU and Ashama, we need to look at the line that connects these two towns on the map and count the number of lines that cross the line connecting the two towns. According to the scale, each line represents 1,500 persons. So, if we count the number of lines that cross the line connecting IZABU and Ashama, we can determine the number of passengers who travelled between these two towns. Upon counting, we can see that there are 8 lines that cross the line connecting IZABU and Ashama. Therefore, the number of passengers who travelled between IZABU and Ashama in the year 2001 was 8 lines x 1,500 persons/line = 12,000 persons. Therefore, the answer is 12,000.

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The Earth has 360 degrees of longitude, and there are 24 standard time zones spread across the Earth's surface, with each standard time zone covering 15 degrees of longitude. Therefore, a country with a longitudinal extent of 150 degrees would cover 10 standard time zones (150/15). The number of standard time zones a country covers depends on the country's longitudinal extent, and how many 15 degree segments that extent covers. So, the correct answer is 10.

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Igneous intrusions are formed when magma solidifies and becomes rock. There are several types of igneous intrusions, and they can be classified based on their shape, size, and orientation. A sill is a type of igneous intrusion that is formed when magma is injected parallel to the layers of existing rock and solidifies. This creates a horizontal or near-horizontal sheet-like intrusion that is parallel to the surrounding rock. Therefore, the answer is: Sill. A sill is horizontally inclined and can be distinguished from other types of igneous intrusions like dykes, laccoliths, and batholiths, which have different shapes and orientations.

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A settlement type in which buildings are aligned along a road or river is said to be linear. This means that the buildings are arranged in a line or series along the road or river. This type of settlement pattern is often seen in areas with transportation routes, where people and goods need to move easily along a path. Linear settlements can be found in various forms, such as a single row of buildings or a series of parallel rows. They are different from nucleated or clustered settlements, where buildings are grouped together in a tight cluster, and dispersed settlements, where buildings are spread out across the landscape.

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The instrument barometer is used for measuring air pressure. It works by measuring the weight of the air pressing down on the surface of a liquid (usually mercury or water) in a tube. The higher the pressure, the more the liquid is pushed up the tube. This can be used to determine changes in atmospheric pressure, which can indicate changes in the weather.

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One feature that is found in the upper course of a river is a gorge. The upper course of a river is where it begins, typically in upland or mountainous areas, and is characterized by steep gradients, high energy, and narrow channels. Gorges are deep, narrow valleys with steep sides that are formed by the erosive power of the river as it cuts down into the landscape. They are a common feature in the upper course of a river where the water is moving quickly and eroding the surrounding rocks and soil. Levees, ox-bow lakes, and deltas are features that are typically found in the middle and lower courses of a river where the water is moving more slowly and has less erosive power.

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Longitude is the angular distance of a location on Earth's surface east or west of the Prime Meridian, which is an imaginary line that runs from the North Pole to the South Pole and passes through Greenwich, England. Two opposite longitudes form a Great Circle. A Great Circle is a circle on the surface of a sphere that has the same center as the sphere. It is the largest possible circle that can be drawn on a sphere and divides the sphere into two equal hemispheres. Therefore, the answer is: a Great Circle. Two opposite longitudes form a Great Circle, while the Equator is an imaginary circle that lies at 0 degrees latitude, the International Dateline is an imaginary line that runs roughly from the North Pole to the South Pole and defines the change of calendar days, and the Arctic Circle is an imaginary circle that lies at 66.5 degrees North latitude.

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Subsistence farming is practiced when people grow crops for their own consumption. The goal of subsistence farming is to produce enough food to feed a family or community, rather than for sale or trade. This type of farming is often found in rural or remote areas where there is limited access to markets for buying or selling goods. Subsistence farming is different from growing only one crop, growing many crops for export, or exporting only one crop. These activities are focused on producing crops for sale or trade, rather than for personal consumption. In simple terms, subsistence farming is when people grow crops to feed themselves and their families, rather than for sale or trade.

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The term relative location of a settlement refers to the position of the settlement in relation to other places or landmarks. It describes where a settlement is located in relation to other towns, cities, mountains, rivers, or other important features in the surrounding area. This information can be useful for understanding the accessibility and connectivity of the settlement, as well as its potential for trade or transportation. It does not refer to the nature of the land, whether the settlement is inhabited by relatives, or an imaginary point on a settlement.

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Caverns, dry valleys, and underground drainage are associated with limestone areas. Limestone is a sedimentary rock that is formed from the accumulation of calcium carbonate over time. It is easily dissolved by water, which can create underground drainage systems and caverns. Caverns are large underground chambers or cave systems that are formed by the erosion of limestone by water. Dry valleys are valleys or channels that are formed when a river or stream flows underground through a limestone area, leaving the surface dry. Mountainous areas can also have caverns and underground drainage, but limestone areas are the most commonly associated with these features due to the unique properties of the rock. Coastal areas are typically associated with erosion by the sea and the formation of sea caves. Desert areas are characterized by low precipitation and are less likely to have extensive underground drainage systems.

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Rapid population growth occurs when the number of births exceeds the number of deaths in a population. This can be influenced by several factors, including improved medical care, which reduces the number of deaths, and an absence of natural hazards that can also cause death. Additionally, if family planning methods are not widely used, then there may be a higher number of births, which can contribute to rapid population growth. Therefore, the absence of factors that limit population growth, along with improvements in healthcare, can lead to a rapid increase in population.

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The busiest ocean trade route is the North Atlantic route. The North Atlantic route is a major shipping lane that connects Europe to North America, passing through the Atlantic Ocean. It is the busiest ocean trade route due to the high volume of goods and materials that are transported between Europe and North America, including crude oil, manufactured goods, and food products. The route is also significant because it connects the major ports of Europe, such as Rotterdam and Antwerp, to major ports in North America, such as New York and Montreal. The North Atlantic route is a critical component of global trade, and the high volume of shipping traffic on this route makes it the busiest ocean trade route in the world.

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Unfortunately, I cannot answer this question without additional context. The District that you are referring to is not specified, and there is no information provided about what "Proga," "Coura," "Hop," or "NITY" refer to. If you can provide more details or clarify your question, I would be happy to help you.

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South-western Nigeria is densely populated in Tropical Africa. Densely populated areas are those with a high concentration of people living in a given area. In Tropical Africa, there are several factors that influence population density, including climate, soil, vegetation, and water resources. South-western Nigeria has a high population density compared to the other regions mentioned. This is due to several reasons, including favorable climate and fertile soil, which are suitable for agriculture. Also, the region is home to several urban centers, including Lagos, which is one of the most populous cities in Africa. The middle belt of West Africa, the Sahel region of West Africa, and the Niger Delta have lower population densities compared to South-western Nigeria. The middle belt of West Africa is characterized by savannah grassland, while the Sahel region of West Africa is characterized by arid and semi-arid climate. The Niger Delta region is dominated by a network of rivers, creeks, and swamps, which make the area difficult to inhabit. Therefore, South-western Nigeria is the most densely populated area in Tropical Africa among the regions mentioned.

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To determine the local time in Town X at 45° E when it is noon at 0°, we need to calculate the time difference between the two locations and add it to or subtract it from noon at 0°. Since every 15 degrees of longitude represents one hour of time difference, the longitude difference between 0° and 45° E is 45 ÷ 15 = 3 hours ahead of the 0° time zone. So, if it is noon at 0°, it would be 3:00 pm in Town X (0 + 3 = 3) since Town X is 3 hours ahead of the 0° time zone. Therefore, the answer is 3:00 pm.

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(a) A lake is a large body of standing water that is surrounded by land. Lakes can be of various sizes, from small ponds to large reservoirs, and can be found in many different environments, including mountains, plains, and coastal areas.

(b) The formation of lakes by wind erosion occurs when wind blows sand and other sediment from one location to another, causing the buildup of sand dunes. Over time, the dunes can grow and block the flow of water, creating a depression that eventually fills with water and forms a lake. This process can take thousands of years and is commonly seen in arid and semi-arid regions.

(c) Three benefits of lakes to man include:

1. Water Supply: Lakes serve as a source of fresh water for drinking, irrigation, and other uses.
2. Recreational Opportunities: Lakes offer opportunities for fishing, boating, swimming, and other forms of recreation, providing places for people to enjoy the outdoors and spend time with friends and family.
3. Habitat for Wildlife: Lakes provide important habitats for many species of plants and animals, including fish, birds, and mammals. These habitats support biodiversity and play a critical role in maintaining the overall health of ecosystems.

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(a) To construct proportional circles to represent the data, we need to follow these steps:

1. Determine the scale of the map: For this question, we are told that 1 cm on the map represents 3 farm units.
2. Multiply the number of farm units in each village by the scale factor: For example, for Amana village, we have 45 farm units multiplied by the scale factor of 3, which gives us 135 cm.
3. Draw a circle for each village: The circle for Amana village will have a diameter of 135 cm, the circle for Igede village will have a diameter of 108 cm, and the circle for Otukpo village will have a diameter of 162 cm.
4. Shade or color each circle: to differentiate them from each other.

(b) Two disadvantages of proportional circles are:

1. Difficulty in accurate comparison: Proportional circles are not suitable for precise comparisons because the size of the circles can be difficult to compare accurately. This is especially true when the differences between the values being represented are small.
2. Limited representation: Proportional circles are limited in their ability to represent data because they can only show one variable at a time. If we want to represent more than one variable, we would need to use multiple proportional circles, which can be confusing and cluttered.

In summary, to construct proportional circles to represent data, we need to determine the scale of the map, calculate the diameter of each circle using the scale factor, and draw and shade each circle accordingly. However, proportional circles have limitations such as difficulty in accurate comparison and limited representation of data.

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Road transportation plays a critical role in the development of a country. Here is a geographical account of road transportation under the following headings:

(a) Three Advantages:

1. Accessibility: Road transportation makes it possible for people to access remote areas and connect with different parts of the country. It provides a flexible and convenient means of transportation.
2. Economic growth: Good road networks facilitate the movement of goods and services from one place to another, which in turn leads to increased economic growth.
3. Employment opportunities: The development of road networks leads to the creation of employment opportunities for people in the transportation sector. This includes drivers, mechanics, and other support staff.

(b) Three Disadvantages:

1. Congestion: As more people use road transportation, traffic congestion becomes a major issue, especially in urban areas. This can lead to increased travel time and decreased productivity.
2. Accidents: Road accidents are a significant disadvantage of road transportation. These accidents can result in injuries, fatalities, and economic losses.
3. Environmental impact: Road transportation has a negative impact on the environment, including air and noise pollution, as well as deforestation.

(c) Four Contributions to Development:

1. Regional integration: Road transportation plays a significant role in regional integration, facilitating trade and commerce between different regions and countries.
2. Tourism development: Good road networks provide access to tourist destinations, contributing to the development of the tourism industry.
3. Urbanization: Road transportation facilitates urbanization, allowing people to move from rural to urban areas in search of employment opportunities.
4. Agricultural development: Good road networks make it possible to transport agricultural produce from rural areas to urban centers, contributing to the development of the agricultural sector.

In conclusion, while road transportation has its advantages, it also has some disadvantages. However, its contributions to development cannot be overlooked. It is essential to manage the negative impacts of road transportation while maximizing its benefits.

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(a)

• National park in the north: Kainji Lake National Park.
• National park in the south: Cross River National Park.
• Calabar town is located in the southeastern part of Nigeria, near the coast of the Gulf of Guinea.

(b) Four factors that retard tourism development in Nigeria include:

1. Inadequate Infrastructure: Nigeria faces challenges with its transportation, power supply, and telecommunications infrastructure, which can make it difficult for tourists to travel within the country and access tourist sites.
2. Political Instability: Political instability, including conflict, unrest, and corruption, can deter tourists from visiting Nigeria.
3. Safety Concerns: Nigeria has a high crime rate, which can make tourists feel unsafe and discourage them from visiting.
4. Lack of Marketing and Promotion: Nigeria has limited marketing and promotion efforts to promote its tourist destinations, which can result in a lack of awareness among potential tourists.

(c) Three ways to promote tourism in Nigeria include:

1. Improving Infrastructure: Improving transportation, power supply, and telecommunications infrastructure can make it easier for tourists to travel within Nigeria and access tourist sites.
2. Enhancing Security: Improving safety and reducing crime can help to create a more welcoming and secure environment for tourists.
3. Marketing and Promotion: Increasing marketing and promotion efforts to promote Nigeria's tourist destinations can raise awareness and encourage more people to visit. This can include showcasing the country's rich cultural heritage, natural beauty, and unique attractions.

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(a)

(i) Characteristics of a Time Zone:

1. Geographical Division: Time zones are geographical divisions that are used to organize the world into 24 equal parts based on longitude.
2. Standard Time: Each time zone has a standard time that is used as a reference for local time.
3. Hour Offset: Time zones are offset from each other by one hour, with the exception of a few places where the offset is half an hour.
4. Daylight Saving Time: Some countries within a time zone may observe daylight saving time, which temporarily adjusts the standard time by one hour.

(ii) Characteristics of the International Dateline:

1. Longitude 180°: The International Dateline is located at longitude 180° and separates the Eastern Hemisphere from the Western Hemisphere.
2. Date Change: When crossing the International Dateline, the date changes by one day.
3. Time Zones: The International Dateline is located within the time zone boundary and acts as a boundary between two time zones.
4. Standard Time: The International Dateline does not have a standard time and serves as a reference for time zone calculations.

(b)

Given that the time in town A is 9.00am and the time in town B is 6.00pm, we can conclude that the time difference between the two towns is 9 hours. Since the Earth rotates 360° in 24 hours, this means that each hour represents a 15° difference in longitude.

Therefore, the longitude of town B can be calculated as follows:

Longitude of town B = Longitude of town A + (Time difference * 15° per hour)
Longitude of town B = 30° W + (9 hours * 15° per hour) = 30° W + 135° = 165° W

In simple terms, the longitude of town B can be found by adding the time difference between the two towns (9 hours) to the longitude of town A (30° W). The result is 165° W, which is the longitude of town B.

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Chemically formed sedimentary rocks are formed from the precipitation of minerals from solution. The minerals come from the chemical weathering of rocks and are carried in solution by water. As the water evaporates, the minerals precipitate and form a sediment. Over time, the sediment is compacted and cemented to form a solid rock.

(a) Mode of formation: Chemically formed sedimentary rocks are formed by the precipitation of minerals from solution.

(b) Three examples:

1. Limestone: Limestone is a sedimentary rock that is mainly composed of calcium carbonate. It is formed from the accumulation of the shells and skeletal fragments of marine organisms such as corals, molluscs, and foraminifera.
2. Rock salt: Rock salt is a sedimentary rock that is mainly composed of halite (sodium chloride). It is formed from the evaporation of salty water in shallow basins.
3. Chert: Chert is a sedimentary rock that is mainly composed of microcrystalline quartz. It is formed from the precipitation of silica from solution in the pores of other rocks.

(c) Four importance:

1. Building materials: Limestone is a valuable building material that is used in the construction of buildings, roads, and bridges.
2. Industrial minerals: Chemically formed sedimentary rocks such as rock salt and gypsum are important sources of industrial minerals.
3. Petroleum reservoirs: Chert is an important component of petroleum reservoirs and helps to trap and hold oil and gas.
4. Fossil preservation: Chemically formed sedimentary rocks such as limestone and chert are important for the preservation of fossils. The fine-grained texture of these rocks helps to preserve the delicate structures of fossils.

In summary, chemically formed sedimentary rocks are formed by the precipitation of minerals from solution. Limestone, rock salt, and chert are three examples of chemically formed sedimentary rocks, each with their unique characteristics. These rocks are important for building materials, industrial minerals, petroleum reservoirs, and fossil preservation.