JAMB UTME - Geography - 2023

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Chemical weathering is a process in which the chemical composition of rocks and minerals is altered due to exposure to certain substances or environmental conditions. It plays a significant role in the breakdown and decomposition of rocks over time. Out of the options given, **frost action** is not a process of chemical weathering. Frost action, also known as freeze-thaw weathering, refers to the physical breakdown of rocks caused by repeated freezing and thawing of water within the rock fractures. It is a type of physical weathering, not chemical. Now let's briefly explain the other three options and how they relate to chemical weathering: 1. **Hydrolysis** is a chemical process in which water reacts with minerals in the rock, leading to their breakdown. Minerals such as feldspar and mica are commonly affected by hydrolysis. Water molecules interact with these minerals, causing them to break down into new minerals or dissolved ions. This process weakens the rock's structure and contributes to its gradual degradation. 2. **Oxidation** is another chemical process that occurs when certain minerals in rocks react with oxygen in the presence of water or air. This reaction causes the minerals to undergo a chemical change, resulting in the formation of new compounds. For example, when iron minerals in rocks come into contact with oxygen, they can oxidize and form iron oxide, more commonly known as rust. This process weakens the rock and makes it more susceptible to further weathering. 3. **Carbonation** is the chemical weathering process associated with the dissolution of carbon dioxide in water, forming carbonic acid. This acid reacts with minerals such as calcium carbonate (present in rocks like limestone and marble), leading to their dissolution. Carbonation is a common process in regions with a high concentration of carbon dioxide in the atmosphere or in areas where water with dissolved carbon dioxide comes into contact with rocks. In conclusion, **frost action** is not a process of chemical weathering but rather a form of physical weathering. Hydrolysis, oxidation, and carbonation, on the other hand, are all examples of chemical weathering processes that contribute to the degradation and alteration of rocks over time.

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Shale rocks are made of clay-sized particles and have a laminated appearance. They are a type of organica sedimentary rock.

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Jos plateau is a Volcanic plateau . It possess volcanic features such as a dome, single vents and clusters of 3-4 cones aligned.

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The buying and selling of goods and services within a country is known as internal trade.

Internal trade refers to the exchange of goods and services between individuals, businesses, and organizations within the borders of a country. It involves the transfer of goods and services from producers to consumers or from one business to another within the same country.

For example, when you go to a local store to buy groceries or when a company sells its products to customers within the country, it is considered internal trade.

Internal trade is an essential part of a country's economy as it enables the circulation of goods and services within the country, stimulates economic growth, creates job opportunities, and fulfills the needs and wants of the people.

International trade, on the other hand, refers to the exchange of goods and services between different countries. Barter is a system of trade where goods or services are exchanged directly without the use of money. Foreign trade specifically refers to the trade between different countries or the import and export activities of a country.

Therefore, in this context, the correct term for the buying and selling of goods and services within a country is internal trade.

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The statement that distinguishes rotation from revolution is that "The earth rotates on its axis while it revolves around the sun in an elliptical orbit." Rotation refers to the spinning of an object around its own axis. In the case of the Earth, it rotates on an imaginary line called its axis. This rotation is responsible for various phenomena like the change between day and night. As the Earth rotates, different parts of it are exposed to the Sun's light, creating the cycle of day and night. Revolution, on the other hand, refers to the movement of an object around another object in space. In the case of the Earth, it revolves around the Sun in an elliptical orbit. This revolution takes approximately 365.25 days to complete, which gives us a year. So, to summarize, rotation refers to the spinning of an object on its axis, causing phenomena like day and night. Revolution refers to the movement of an object around another object in space, giving us the concept of a year.

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A line joining all points of equal salinity is called an isohaline. In simpler terms, an isohaline is a line that connects points in a body of water that have the same level of salinity or saltiness. It is similar to a contour line you might see on a map that connects points of equal elevation. Salinity refers to the amount of salt dissolved in water. Different areas of the ocean, sea, or even a lake can have varying levels of salinity. An isohaline helps us visualize these varying levels by connecting the points with the same salinity. By studying and mapping isohalines, scientists can gain valuable insights into the distribution and movement of saltwater in different bodies of water. This information is important for understanding ocean currents, marine life habitats, and even for managing freshwater resources. To summarize, an isohaline is a line that connects points with the same salinity in a body of water. It helps us understand the distribution and movement of saltwater and is valuable in various scientific studies and resource management.

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A wind-deposited landform refers to a geological feature that is created or shaped by the action of wind carrying and depositing sediments. In this context, out of the four options given, the one that is a wind-deposited landform is **loess**. Loess is a specific type of sediment that is composed of fine particles of silt and clay that have been blown by wind over long distances and eventually deposited. It is typically pale yellow or light brown in color and has a very fine texture. Loess deposits often form in regions with strong and consistent winds, such as dry deserts or the margins of glacial systems. These sediments accumulate over time, often in thick layers, creating distinct landforms. One characteristic feature associated with loess is its ability to be easily eroded by wind and water. This erosion gives rise to unique landforms, such as **yardangs** and **deflation hollows**, which are also mentioned in the given options. A yardang is a ridge of rock that has been carved and streamlined by wind erosion. The wind scours away the loose sediment, leaving behind elongated ridges that run parallel to the prevailing wind direction. Yardangs can vary in size from a few meters to several kilometers long. A deflation hollow, on the other hand, is a depression in the landscape that forms when loose sediments are eroded away by wind, leaving behind a lowered area. These hollows can occur individually or in groups, and their size and shape depend on the intensity and duration of wind erosion. While both yardangs and deflation hollows are features associated with wind erosion, they are not technically wind-deposited landforms since they are created by the removal of sediment rather than the deposition of sediment. In summary, out of the options given, the wind-deposited landform is **loess**. It is a type of fine sediment made of silt and clay particles that are transported and deposited by the wind. Yardangs and deflation hollows, although associated with wind erosion, are not specifically wind-deposited landforms.

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A barchan is a cresentic or moon-shaped structure. A barchan is formed when an obstacle like rocks impedes or prevents the movement of wind

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The river regime generally describes the character of the typical fluctuations of a flow of a river, but can also refer to the mathematical relationship between the river discharge and its width, depth and slope

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The type of agriculture described here is called dry farming.
Dry farming is a method of agriculture that focuses on conserving water in areas where water supply is limited. It is commonly used in regions with arid or semi-arid climates where rainfall is scarce and unreliable.
In dry farming, the goal is to maximize the use of available moisture in the soil and minimize water loss through evaporation. This is achieved through various practices such as ploughing, mulching, and harrowing.
Ploughing helps to break up the soil surface and create furrows or ridges, which helps to trap and retain moisture in the soil. This prevents excessive evaporation and allows the soil to hold water for a longer period of time.
Mulching involves covering the soil with a layer of organic materials such as straw, leaves, or crop residues. This helps to reduce evaporation by shading the soil surface and slows down moisture loss. Mulch also helps to improve soil structure, retain water, and suppress weed growth.
Harrowing is the process of loosening the top layer of soil after ploughing or planting. It helps to create a fine, crumbly soil structure that reduces water runoff and allows rain or irrigation water to penetrate deeper into the soil.
By practicing these techniques, dry farmers are able to conserve water and create favorable conditions for crop growth even in areas with limited rainfall. This allows them to sustain crop production in successive years without relying heavily on external sources of water.
In summary, dry farming is a method of agriculture that conserves water in arid or semi-arid regions by employing practices such as ploughing, mulching, and harrowing. These techniques help to retain moisture in the soil, reduce water loss, and enable crop production in successive years.

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The most common form of migration experienced in countries of Tropical Africa is **rural-urban migration**. This refers to the movement of people from rural areas, such as villages and small towns, to urban areas, such as cities and towns. There are various reasons why rural-urban migration is prevalent in Tropical Africa. One of the main factors is the search for better economic opportunities. Urban areas tend to offer more job opportunities, higher wages, and better living conditions compared to rural areas. Many people from rural communities migrate to cities in hopes of finding better employment and improving their standard of living. Another important factor contributing to rural-urban migration is the availability of social amenities and services in urban areas. Cities often have better access to education, healthcare, infrastructure, and recreational facilities. People may migrate to urban centers to access these services and provide better opportunities for their families. Moreover, urban areas serve as economic and cultural hubs, attracting people from rural areas seeking to benefit from the diversity and dynamism of city life. Cities offer a wide range of social and cultural activities, entertainment options, and opportunities for networking and socializing. However, it is important to note that rural-urban migration also presents some challenges. The rapid influx of people into cities can lead to overcrowding, strain on infrastructure, and increased competition for resources and jobs. Additionally, migration can have an impact on rural communities as they may experience a loss of human capital and skills. In summary, rural-urban migration is the most common form of migration in countries of Tropical Africa due to the search for better economic opportunities, access to social amenities, and the attraction of urban culture and lifestyle. While it brings benefits to individuals and urban areas, it also poses challenges that need to be addressed for sustainable development.

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Solar energy is the energy gotten from the sun. The sun is the largest (star and its also the ultimate source of light and energy to all the planets. Coal, gas and Nuclear energy are hot renewable(i.e they cannot be reused when exhausted)

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The instrument used to measure the duration of sunshine is called the **campbell-stokes recorder**. This instrument is specifically designed to measure the amount of sunlight received at a particular location over a given period of time. The campbell-stokes recorder consists of a glass sphere that is mounted in a metal frame. This sphere acts as a lens, focusing the sunlight onto a specially designed card or paper underneath. The card or paper is positioned in such a way that it is slightly above the focal point of the lens. When sunlight passes through the lens and focuses on the card, it causes the card to heat up. As a result, a burn mark or a scorch is left on the card. By measuring the length of the burn mark, we can determine the duration of sunshine. The campbell-stokes recorder is widely used in meteorology and climatology to monitor and document the amount of sunshine received in a given area. It is a simple and effective instrument that provides valuable data for studying weather patterns, climate change, and solar energy potential. In conclusion, the instrument used to measure the duration of sunshine is the campbell-stokes recorder, which uses a glass sphere to focus sunlight onto a card or paper and measures the length of the resulting burn mark.

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A slope is said to be even when the contours are **equally placed**. This means that the contours are evenly spaced apart from each other. When the contours are evenly spaced, it indicates that the slope of the land is relatively consistent throughout the area. Imagine looking at a map or a cross-section of a hill or mountain. Contours are the lines on the map that connect points of the same elevation. They give us a visual representation of how steep or gentle the slope is at any given point. When the contours are evenly spaced, it means that the difference in elevation between each contour line is consistent. This indicates that the slope is gradual and not too steep. For example, if we have contour lines that are evenly spaced apart by 10 meters, it means that the slope of the land is changing by approximately 10 meters in height with each contour line. On the other hand, if the contours are irregularly spaced, it means that the slope is varying more dramatically. This can indicate areas of steep cliffs or sudden changes in elevation. In summary, an even slope is characterized by **equally placed** contours, indicating a gradual and consistent change in elevation.

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To determine which month of the year has the highest temperature in station Z, we should analyze the data given in the table.
Looking at the table, we can see that the **temperature values** are given in the column labeled "Temperature (°C)". We need to find the month with the highest temperature value.
By examining the temperature values for each month, we can observe the following:
- In **April**, the temperature is 27°C - In **May**, the temperature is 30°C - In **June**, the temperature is 32°C - In **August**, the temperature is 29°C
From this information, we can clearly see that the month with the **highest temperature** in station Z is **June**, with a temperature of **32°C**.
Therefore, the answer to the question is that **June** is the month of the year with the highest temperature in station Z, as evidenced by the table.

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Denudation is the process of wearing away the Earth's surface by various agents such as water, wind, and ice. It involves the removal and transportation of rocks, sediments, and soil. The correct sequence in which denudation occurs is:
Weathering → Erosion → Deposition
1. Weathering: This is the first step in denudation. Weathering refers to the breakdown and decomposition of rocks and minerals at or near the Earth's surface. It can occur through physical, chemical, or biological processes. Physical weathering involves the mechanical breakdown of rocks into smaller fragments due to factors like temperature changes, frost action, or plant roots. Chemical weathering involves the alteration of rock composition through processes like dissolution, oxidation, or hydrolysis. Biological weathering refers to the breakdown of rocks by living organisms such as plants and animals.
2. Erosion: Once weathering has broken down the rocks, erosion takes place. Erosion is the process of removing and transporting the weathered materials from their original location to a new location. This is often done by agents such as water, wind, glaciers, or gravity. For example, water erosion occurs when rainfall or flowing water carries away sediments, creating channels, gullies, and valleys. Wind erosion happens when strong winds pick up and transport loose particles, leading to the formation of sand dunes and desert landscapes.
3. Deposition: After weathered materials have been eroded and transported, they are eventually deposited. Deposition occurs when the eroded particles and sediments settle down and come to rest in a new location. This can happen when the transporting agent loses energy, such as when a river slows down or when wind speed decreases. Deposited materials can form various landforms such as deltas, alluvial plains, or beaches.
In summary, denudation starts with weathering, where rocks are broken down. Then erosion takes place, transporting the weathered materials. Finally, the eroded materials are deposited in a new location.

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A block mountain is formed as a result of faulting, specifically a type of fault called a normal fault.
When the Earth's crust experiences stress, it can cause rocks to break along fault lines. In the case of a normal fault, the rocks on one side of the fault move downward relative to the rocks on the other side. This downward movement creates a step-like feature on the Earth's surface, with one side lower than the other. This step-like feature is what we call a block mountain.
As time goes on, the forces of erosion, such as wind, water, and glaciers, start to wear away at the block mountain. However, the harder and more resistant rocks that make up the mountain are less easily eroded compared to the softer surrounding rocks. This causes the block mountain to stand out even more as a prominent and elevated feature in the landscape.
So, to summarize, a block mountain is formed when the Earth's crust experiences faulting, specifically a normal fault. The downward movement of rocks on one side of the fault creates a step-like feature on the Earth's surface, which we call a block mountain. Erosion then works to shape and define the mountain's features over time.

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Mediterranean vegetation consists largely of broad-leaved evergreen shrubs having woody stems with thick roots.

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The broad-leafed evergreen and dense equatorial forest of the Amazon basin is called selvas. Selvas is a term used to describe the lush, vibrant rainforest found in the Amazon.
These forests are characterized by their tall trees with large, broad leaves that can capture as much sunlight as possible. The leaves of these trees stay green all year round, giving the forest a constant appearance of being "evergreen."
The Amazon rainforest is also known for its incredible biodiversity, with a wide variety of plant and animal species living in this habitat. This is due to the constant warm and humid climate, as well as the diverse range of ecosystems within the region.
The dense and thick vegetation in the selvas plays a crucial role in maintaining the health of our planet. It serves as a carbon sink, absorbing large amounts of carbon dioxide and releasing oxygen through photosynthesis. Additionally, the Amazon rainforest is often referred to as the "lungs of the Earth" because of its significant contribution to global oxygen production.
In conclusion, the broad-leafed evergreen and dense equatorial forest of the Amazon basin is known as selvas. It is a unique and important ecosystem with immense biodiversity and crucial ecological functions.

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The major crop grown in the El Juf Basin of Mali is cotton. Cotton is a plant that is mainly grown for its fiber, which is used to make fabrics and textiles. The El Juf Basin in Mali has favorable conditions for growing cotton, such as a warm climate and fertile soil.
Cotton plants require a long growing season with plenty of sunshine and a moderate amount of rainfall. The El Juf Basin receives sufficient rainfall and has an irrigation system in place to ensure that the cotton plants are well-watered.
Cotton cultivation in the El Juf Basin provides a significant source of income for the local farmers and contributes to the economy of Mali. Cotton farms in this region employ many people and support the livelihoods of the local communities.
In summary, the major crop grown in the El Juf Basin of Mali is cotton due to its suitability to the region's climate and soil conditions.

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Industrial activities such as production, construction etc, monoculture and lumbering are responsible for erosion in the tropics

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When weathering occurs on hill slopes, the rock debris usually pile up at the bottom of the hill slope to form **scrree**. Scree is a deposition of loose rock fragments that have accumulated at the base of a steep slope or cliff. It is formed as a result of the continuous process of weathering, erosion, and gravity. Weathering is the breakdown of rocks by natural processes, such as wind, water, and temperature changes. This causes rocks to become smaller and more fragmented over time. Erosion is the process of transporting the fragmented rock material down the slope. Gravity plays a significant role in moving the loose rock fragments towards the bottom of the hill slope. As the weathered rock fragments accumulate at the base of the slope, they form a pile of loose debris called scree. Scree can range in size from small pebbles to larger rocks. It is usually found on steep slopes or cliffs where the force of gravity pulls the loose rock down and accumulates it at the bottom. In conclusion, when weathering occurs on hill slopes, the rock debris piles up at the bottom to form scree.

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avannas represents the vast majority of the areas which are characterised by a layerof perenial herbaceous plants, such as sedges with varrying degree of scrubs

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Rye is not a plantation crop. Plantation crops are large-scale crops that are grown specifically for commercial purposes, often on plantations or large farms. These crops are usually labor-intensive and require specialized farming techniques. Cocoa, oil palm, and rubber are all examples of plantation crops. Cocoa is the main ingredient in chocolate, oil palm produces palm oil used in various products, and rubber is used to make tires and other rubber products. On the other hand, rye is a grain crop that is typically grown in small to medium-sized farms. It is used primarily for making bread, whiskey, and animal feed. Unlike plantation crops, rye does not require extensive labor or specialized farming techniques. In summary, rye is not a plantation crop because it is grown on smaller farms and does not have the same commercial scale as crops like cocoa, oil palm, and rubber. These plantation crops have large-scale production and are used in various industries.

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The sun is vertically overhead at the tropic of Capricorn on December 22nd. To understand why, we need to know a few things about the Earth's tilt and its movement around the sun. The Earth is tilted on its axis at an angle of about 23.5 degrees. This tilt is what gives us our seasons. During the year, the Earth moves around the sun in an elliptical path. On two specific days, called the solstices, the sun reaches its highest or lowest point in the sky. These are the days when the tilt of the Earth is most noticeable. On December 22nd, the Northern Hemisphere is tilted away from the sun. This means that the sun appears lower in the sky and its rays are more spread out. Meanwhile, the Southern Hemisphere is tilted towards the sun. This tilt causes the sun to appear higher in the sky and its rays to be more concentrated. The tropic of Capricorn is located at about 23.5 degrees south of the equator. On December 22nd, the sun is directly overhead at this latitude because the tilt of the Earth causes the sun's rays to be focused at that point. In summary, on December 22nd, the sun is directly overhead at the tropic of Capricorn because of the Earth's tilt and its position in its orbit around the sun.

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It should be noted that landforms produced by faulting are Rift valley and Block mountain. Rift valley occurs when there are tensional and compression forces operating. Two parallel faults occur and there will be gravitational force leading to the sinking of the land between the faults.

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Water vapour is turned into water droplets by the process of **condensation**. Condensation occurs when water vapor, which is in the gaseous state, comes into contact with a cool surface or cool air. When the temperature of the water vapor decreases, the water molecules slow down and move closer together. This causes the water vapor to transform into liquid water, forming water droplets. To understand this process better, think of a glass of cold water on a warm day. As the warm air comes into contact with the cold surface of the glass, the water vapor in the air loses heat energy and condenses into water droplets on the outside of the glass. This is why you observe water droplets forming on the glass. Similarly, when warm, moist air rises and comes into contact with cooler air in the atmosphere, or when it encounters cool surfaces such as windows, mirrors, or grass in the early morning, condensation occurs, and water droplets are formed. In summary, condensation is the process where water vapor changes from a gaseous state to a liquid state by cooling down, resulting in the formation of water droplets.

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The sparse population in the middle belt of West Africa can be traced to all of the following except the concentration of industries.

1. Inter-ethnic war: Conflict between different ethnic groups can cause displacement and hinder population growth in the affected areas. It leads to a disruption in the social fabric and discourages people from settling in these regions.

2. Tsetse fly infestation: The presence of tsetse flies, which are carriers of the sleeping sickness disease, can greatly affect human habitation. These flies are notorious for their bites which can transmit the disease to humans and livestock. The presence of tsetse flies in the middle belt of West Africa makes it difficult for people to inhabit the area due to health risks.

3. Arab slave trade in the North: The Arab slave trade, which took place predominantly in North Africa, resulted in the forced migration and enslavement of many African populations. This historic slave trade did not have a direct impact on the sparse population in the middle belt of West Africa.

4. Concentration of industries: The concentration of industries usually leads to urbanization and increased population in certain areas. This option does not contribute to the sparse population in the middle belt of West Africa.

Therefore, the correct answer is that the sparse population in the middle belt of West Africa cannot be traced to the concentration of industries.

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Nigeria's biggest export is crude oil, a commodity that represents over three-quaters(78.7%) of its total exported goods by value.

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Political and economic integration can be hindered by powerful colonial ties, religion and political instability but currency should not be an obstacle because there should be an established exchange rate.

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The world is divided into torrid, temperate, and frigid zones under the Greek system of climate classification. 1. Torrid Zone: This zone is the closest to the equator and is known for its hot and humid climate. It experiences high temperatures throughout the year with minimal variations. The torrid zone is characterized by tropical rainforests, savannas, and deserts. 2. Temperate Zone: The temperate zone is situated between the torrid and frigid zones. It has a moderate climate with distinct seasons. The temperatures in this zone vary significantly throughout the year, with warm summers and cool winters. This zone is known for its diverse vegetation, including deciduous forests and grasslands. 3. Frigid Zone: The frigid zone is located in the extreme north and south of the Earth, near the poles. It is known for its extremely cold temperatures, especially during the winter season. The frigid zone is covered with ice, and only a few plants and animals can survive in this harsh environment. In summary, the Greek system of climate classification divides the world into torrid, temperate, and frigid zones, depending on factors such as temperature, humidity, and vegetation.

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A settlement where two rivers meet is called a confluence town. This term is used to describe a place where two rivers merge or come together. It is also known as a river confluence or simply a confluence. In a confluence town, the two rivers join and flow as one. This merging of rivers creates a unique geographical feature and often leads to the formation of a settlement. The rivers may flow side by side before merging, or one river may flow into the other. The confluence point can be visible as a distinct meeting point or an area where the waters mix. Confluence towns have been historically significant because they often provided essential resources and transportation routes. The availability of water from two rivers made these settlements ideal for various activities such as fishing, trade, and agriculture. The confluence also facilitated transportation and trade routes as it served as a natural meeting point for people traveling along the rivers. These settlements tend to develop into vibrant communities, attracting people for their economic advantages and accessibility. Over time, confluence towns may grow and expand, becoming important centers of commerce, culture, and administration. In summary, a settlement where two rivers meet is called a confluence town. It is a place where two rivers merge or come together, offering valuable resources and opportunities for economic and social development.

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Aridity is a long term lack of rainfall or moisture. Soil erosion cannot take place in an srid area.

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On June 21, the sun is overhead at the tropic of cancer, resulting in June or summer scistics

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The wettest month of the year is determined by the month with the highest rainfall. From the table, the highest rainfall is 307mm, which occurs in August. Therefore, the wettest month of the year is August.

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A coastline of emergence refers to a type of coastline where the land is rising relative to the sea level. This rise in land can be caused by geological processes such as tectonic movements or isostatic rebound. One example of a coastline of emergence is a **raised beach**. A raised beach is a coastal landform that was once at sea level but has been lifted up above the current sea level. This lifting can occur due to processes like tectonic activity or changes in the Earth's crust. When the land rises, the shoreline shifts upwards, leaving behind a flat or gently sloping platform. This platform, known as a raised beach, is typically located above the reach of waves and tides. It can vary in width and elevation, extending for several kilometers inland. A raised beach often has distinctive features such as wave-cut notches, terraces, and marine deposits like shells or sediments. These features serve as evidence of its former connection to the sea. It is important to note that a raised beach is just one type of coastline of emergence. Other examples include dalmation coasts, ria coasts, and estuarine coasts. However, among the given options, a raised beach best represents a coastline of emergence.

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An urban settlement is where displaced population settle within agglomeration such as a town or city. People are mainly involved in secondary and tertiary activities like manufacturing and construction. Additionally, dispersed settlement is one of the main types of settlement pattern used to classify rural settlement.

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Lake Kossou is Cote d'ivores largest lake. It lies on the Bandama river in the center of the country. It is an artificial lake, created in 1973 by damming the Badama river at kossou

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Soil erosion by rain can occur when the force of raindrops and the resulting surface runoff remove the top layer of soil. This process can be harmful and lead to the loss of fertile soil needed for growing crops and plant growth. There are several factors that can contribute to soil erosion by rain, but one of the options mentioned does not cause it. Let's analyze each option:

Tropical rainstorms: Tropical rainstorms are often associated with heavy rainfall and intense precipitation. The large amount of rainwater can create powerful runoff that can wash away soil particles and contribute to erosion. Therefore, tropical rainstorms can indeed cause soil erosion by rain.

Scanty vegetation: Vegetation, such as plants and trees, plays a crucial role in preventing soil erosion. The roots of plants help hold the soil together, reducing the impact of raindrops and preventing excessive runoff. When vegetation is sparse or absent, there are no roots to anchor the soil, making it more vulnerable to erosion. So, scanty vegetation can contribute to soil erosion by rain.

Steep slopes: Steep slopes can accelerate the process of soil erosion by rain. When rainwater flows down a steep slope, it gains momentum and power, increasing the force with which it hits the soil. This force can dislodge soil particles and carry them away, leading to erosion. Therefore, steep slopes can cause soil erosion by rain.

Aridity: Aridity refers to dryness or a lack of moisture. In arid regions, rainfall is limited, and the soil may be dry and less prone to erosion caused by rain. The lack of significant rainfall reduces the chances of soil particles being dislodged by raindrops or carried away by runoff, making aridity a factor that does not cause soil erosion by rain.

In conclusion, all the options except aridity can contribute to soil erosion by rain. Tropical rainstorms, scanty vegetation, and steep slopes can all increase the likelihood of soil erosion. However, in arid regions where there is a lack of moisture, the risk of soil erosion caused by rain is reduced.

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Exports from Mali are most likely to pass through the sea port at Abidjan. Abidjan is the largest and busiest port in West Africa, located in Cote d'Ivoire. It is strategically positioned along the Gulf of Guinea, making it an ideal gateway for trade in the region. Mali is a landlocked country, which means it does not have direct access to the sea. Therefore, to transport their goods internationally, Mali relies heavily on neighboring countries' ports. Among the given options, Abidjan is the closest and most accessible port for Mali. Abidjan offers excellent shipping facilities, infrastructure, and connections to major shipping lines. It has a well-developed road network that connects it to Mali and other landlocked Sahelian countries, making it a convenient and efficient route for transporting goods. In summary, due to its proximity, connectivity, and efficiency, the sea port at Abidjan is the most likely entry point for Mali's exports.