All practice questions

Question 12401Question →

On a topographical map drawn to a scale of $1 : 40,000$ , a communications cable line is planned between Trigonometrical Station $P$ at an elevation of $680\text{ m}$ and Spot Height $Q$ at an elevation of $200\text{ m}$ . If the straight-line distance measured between $P$ and $Q$ on the map is $12\text{ cm}$ , what is the average gradient of the slope between these two points expressed as a percentage?

10\%

0.1\%

14.17\%

4\%

Show answer & explanation

Answer: $10\%$

Answer

The average gradient of the slope expressed as a percentage is

10\%

.

The slope gradient is calculated by dividing the Vertical Interval (

480\text{ m}

) by the Horizontal Equivalent (

4,800\text{ m}

). Multiplying the ratio

\frac{480}{4,800} = 0.10

by

100

yields

10\%

.

Step-by-Step Solution

1

Calculate the Vertical Interval (VI)

\text{VI} = 680\text{ m} - 200\text{ m} = 480\text{ m}

Vertical Interval is the difference in elevation between the two points.

2

Calculate the Horizontal Equivalent (HE) in meters

\text{Ground distance} = 12\text{ cm} \times 40,000 = 480,000\text{ cm} = 4,800\text{ m}

Multiply the map distance by the scale factor and convert from centimeters to meters (

100\text{ cm} = 1\text{ m}

).

3

Compute the slope gradient as a percentage

\text{Gradient (\%)} = \left( \frac{\text{VI}}{\text{HE}} \right) \times 100 = \left( \frac{480\text{ m}}{4,800\text{ m}} \right) \times 100 = 10\%

Gradient percentage is defined as the ratio of Vertical Interval to Horizontal Equivalent multiplied by 100.

Key Concept

Slope and Gradient Calculation on Topographic Maps

Question 12402Question →

Mediterranean agriculture in Africa is predominantly practiced in the South-Western Cape of South Africa and parts of North Africa. Which of the following crop combinations is most characteristic of this agricultural system?

Grapes, citrus fruits, and wheat

Cocoa, rubber, and oil palm

Groundnuts, cotton, and millet

Coffee, tea, and pyrethrum

Show answer & explanation

Answer: Grapes, citrus fruits, and wheat

Answer

Grapes, citrus fruits, and wheat

Mediterranean agriculture in the South-Western Cape of South Africa and the Atlas region of North Africa specializes in orchard farming, viticulture, and cereal cultivation (grapes, citrus fruits, olives, and wheat) due to the distinct climate with winter precipitation and dry summers.

Step-by-Step Solution

1

Identify climatic conditions of Mediterranean agriculture in Africa

Mediterranean regions (South-Western Cape and North African coast) feature winter rain and summer drought.

Crop suitability is directly governed by seasonal rainfall and temperature patterns.

2

Match environmental conditions to crop characteristics

Fruit trees with thick skins (citrus), deep-rooted vines (grapes), and winter crops (wheat) adapt best to these conditions.

These crops thrive under winter moisture and warm, sunny dry summers.

Key Concept

Mediterranean Agricultural System in Africa

Question 12403Question →

Rural-urban migration remains a primary driver of rapid urban growth in developing countries. Which of the following rural conditions acts as a push factor forcing residents to leave their settlements for urban centers?

Depletion of agricultural soil fertility leading to poor crop yields

Availability of modern medical facilities and specialized healthcare

Presence of diverse manufacturing industries and wage-earning job opportunities

Clustering of residential dwellings along major transportation highways

Show answer & explanation

Answer: Depletion of agricultural soil fertility leading to poor crop yields

Answer

Depletion of agricultural soil fertility leading to poor crop yields

Soil fertility depletion directly undermines rural agricultural production and livelihoods. Because rural economies depend heavily on farming, severe land degradation creates hardship that forces rural dwellers out of their villages to seek survival in urban centers.

Step-by-Step Solution

1

Define push factors in the context of rural-urban migration

Push factors are unfavorable socio-economic or environmental conditions in rural origin areas that force residents to migrate.

Understanding the distinction between push factors (negative rural conditions) and pull factors (positive urban attractions) is key.

2

Evaluate the options against rural push factor characteristics

Declining soil fertility directly impairs agricultural productivity, causing rural poverty and pushing farmers to seek urban employment.

Degraded natural resources in rural areas act directly as economic push motivators.

Key Concept

Rural-Urban Migration Push Factors

Estimated Time:50s

Question 12404Question →

Coastal processes shape coastal environments through marine erosion, transportation, and deposition. Which of the following features is created primarily by coastal deposition?

Oxbow lake

Beach

Scree slope

Marble ridge

Show answer & explanation

Answer: Beach

Answer

Beach

Beaches are temporary or permanent accumulations of sediment (sand, gravel, or pebbles) deposited along the coast by constructive waves where wave energy is low.

Step-by-Step Solution

1

Identify the primary agent of coastal deposition

Constructive waves build up landforms by depositing sediments like sand and pebbles along the shoreline.

Coastal landforms are classified into erosional features (like sea cliffs, arches, stacks) and depositional features (like beaches, spits, bars).

2

Evaluate the landform options against coastal deposition

Beaches consist of accumulated sand and shingle deposited by swash-dominated wave action.

Distinguish coastal marine landforms from river landforms, slope weathering features, and rock metamorphic structures.

Key Concept

Coastal Depositional Landforms

Question 12405Question →

Match each Nigerian mineral or energy resource on the left with its principal deposit location or major production center on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Gold matches with Ilesa (Osun State); Lead and Zinc matches with Abakaliki (Ebonyi State); Lignite (Brown Coal) matches with Asaba (Delta State); Natural Gas Thermal Power matches with Ughelli (Delta State).

Each resource is matched accurately to its primary deposit site or power plant: Gold to Ilesa, Lead and Zinc to Abakaliki, Lignite to Asaba, and Natural Gas Thermal Power to Ughelli.

Step-by-Step Solution

1

Locate key metallic mineral deposits across Nigeria.

Gold is associated with the Ilesa goldfield in Osun State, while major lead and zinc ores are located at Abakaliki in Ebonyi State.

Recall spatial distribution of solid metallic minerals.

2

Locate fuel and energy generation resources.

Lignite deposits are centered around Asaba in Delta State, and natural gas thermal power is generated at Ughelli in Delta State.

Distinguish between fossil fuel deposits and thermal power stations.

Key Concept

Spatial distribution of metallic minerals, solid fuel reserves, and gas power infrastructure in Nigeria.

Question 12406Question →

An ecological study evaluates plant structural adaptations and indicator species across Nigeria's major biomes. Which of the following statements accurately matches a Nigerian vegetation zone with its defining structural adaptation and characteristic flora?

Guinea Savanna: Deciduous trees with thick fire-resistant bark, such as Isoberlinia and Lophira, growing alongside tall tussock grasses

Sudan Savanna: Dense multi-layered evergreen canopy with buttress roots, dominated by oil palm and cocoa trees

Sahel Savanna: Stilt roots and respiratory pneumatophores, predominantly featuring Rhizophora and Avicennia mangrove species

Freshwater Swamp Forest: Short thorny trees, fine-leaved acacias, and ephemeral grasses adapted to nine months of continuous drought

Show answer & explanation

Answer: Guinea Savanna: Deciduous trees with thick fire-resistant bark, such as Isoberlinia and Lophira, growing alongside tall tussock grasses

Answer

Guinea Savanna is accurately defined by deciduous trees with thick fire-resistant bark, such as Isoberlinia and Lophira, interspersed with tall tussock grasses.

The Guinea Savanna covers the broadest area in middle-belt Nigeria and is characterized by open woodland containing fire-resistant trees like Isoberlinia and Lophira, along with tall tussock grasses adapted to annual dry-season burning.

Step-by-Step Solution

1

Analyze the ecological adaptations of the Guinea Savanna belt in Nigeria.

The Guinea Savanna experiences distinct wet and dry seasons with periodic bush fires, leading to adaptations like thick, fire-resistant bark and deciduous leaf-shedding.

Matching structural adaptations to climatic stress identifies the correct ecological belt.

2

Identify key floral species associated with Guinea Savanna.

Dominant species include Isoberlinia, Lophira procera, Daniellia oliveri, and tall grasses (e.g., Pennisetum).

Indicator species verify vegetation zone classification.

3

Evaluate and eliminate options that incorrectly pair northern dry belts with coastal or rainforest adaptations.

Options placing rainforest cash crops in the Sudan zone or mangrove/desert flora in opposing latitudinal extremes are incorrect.

Verifies that distractors contain clear misattributions of vegetation characteristics across Nigeria's north-south gradient.

Key Concept

Vegetation Zones and Floral Adaptations in Nigeria

Estimated Time:2m 0s

Question 12407Question →

Following the illegal dumping of hazardous industrial waste at Koko, Delta State, in 1987, the Nigerian Federal Government promulgated Decree No. 58 of 1988 to establish its pioneer institutional framework for overall environmental protection. Which agency was created by this decree?

Federal Environmental Protection Agency

National Environmental Standards and Regulations Enforcement Agency

National Oil Spill Detection and Response Agency

National Emergency Management Agency

Show answer & explanation

Answer: Federal Environmental Protection Agency

Answer

Federal Environmental Protection Agency (FEPA)

The toxic waste dumping incident in Koko in 1987 exposed major gaps in Nigeria's environmental regulatory legislation. In response, the Federal Military Government promulgated Decree No. 58 of 1988, establishing the Federal Environmental Protection Agency (FEPA) as the statutory authority tasked with protecting the Nigerian environment, monitoring pollutants, and setting national environmental standards.

Step-by-Step Solution

1

Identify the historical catalyst and date specified in the question stem

The event is the 1987 Koko toxic waste dumping in Delta State, leading to legislation in 1988 (Decree No. 58).

Environmental law in Nigeria developed rapidly after the toxic waste dumping event.

2

Match Decree No. 58 of 1988 to the corresponding pioneer environmental agency

Decree No. 58 of 1988 created the Federal Environmental Protection Agency (FEPA).

FEPA was Nigeria's initial statutory body created to set environmental standards and protect natural resources.

Key Concept

Foundational History of Nigerian Environmental Agencies

Question 12408Question →

A topographical map, Map A, drawn to a scale of $1 : 100,000$ , displays a rectangular reservoir measuring $5\text{ cm}$ by $8\text{ cm}$ . When Map A is reduced to create Map B, the reservoir covers an area of $10\text{ cm}^2$ on Map B. What is the representative fraction (R.F.) scale of Map B?

1 : 50,000

1 : 200,000

1 : 400,000

1 : 25,000

Show answer & explanation

Answer: $1 : 200,000$

Answer

The representative fraction scale of Map B is

1 : 200,000

.

The area of the reservoir on Map A is

5\text{ cm} \times 8\text{ cm} = 40\text{ cm}^2

. On Map B, the area is reduced to

10\text{ cm}^2

, giving an area reduction ratio of

\frac{10}{40} = \frac{1}{4}

. Since area scale change is the square of the linear scale change (

n^2

), the linear reduction factor is

\sqrt{\frac{1}{4}} = \frac{1}{2}

. Reducing a map by a linear factor of 2 doubles its scale denominator from

100,000

to

200,000

, resulting in a new scale of

1 : 200,000

.

Step-by-Step Solution

1

Calculate the area of the reservoir on Map A.

\text{Area on Map A} = 5\text{ cm} \times 8\text{ cm} = 40\text{ cm}^2.

The surface area of a rectangular section on a map is obtained by multiplying length by width.

2

Determine the area reduction factor between Map A and Map B.

\text{Area Ratio} = \frac{\text{Area on Map B}}{\text{Area on Map A}} = \frac{10\text{ cm}^2}{40\text{ cm}^2} = \frac{1}{4}.

Dividing the area on the new map by the area on the original map gives the factor of areal change.

3

Calculate the linear reduction factor.

\text{Linear Ratio} = \sqrt{\text{Area Ratio}} = \sqrt{\frac{1}{4}} = \frac{1}{2}.

The change in surface area follows the square of the linear scale change (

n^2

), so taking the square root gives the linear factor (

n

).

4

Calculate the new Representative Fraction (R.F.) for Map B.

\text{New Scale Denominator} = 100,000 \times 2 = 200,000

, yielding a scale of

1 : 200,000$.

Map reduction results in a smaller scale, which increases the scale denominator proportionally to the linear reduction factor.

Key Concept

Map Reduction and Area Scale Relationship

Question 12409Question →

A state transport planning authority in Nigeria is evaluating two infrastructure development phases for a regional transport network. In Phase 1, the network consists of $8$ nodal settlements ( $v$ ) connected by $12$ direct highway corridors ( $e$ ). In Phase 2, the network expands by adding $2$ new settlement nodes and $6$ new highway corridors that integrate into the existing system. What is the net change in the network's Beta index ( $\beta$ ) of topological connectivity from Phase 1 to Phase 2?

An increase of

0.30

A decrease of

0.11

An increase of

1.50

A decrease of

0.90

Show answer & explanation

Answer: An increase of $0.30$

Answer

The topological connectivity increases by

0.30

in the Beta index (

\beta

).

In graph theory applied to transport geography, the Beta index (

\beta

) measures the connectivity of a network graph by dividing the total number of edges (

e

) by the total number of vertices (

v

). In Phase 1,

\beta_1 = 12 / 8 = 1.50

. In Phase 2, the network accumulates

8 + 2 = 10

vertices and

12 + 6 = 18

edges, yielding

\beta_2 = 18 / 10 = 1.80

. The net change in connectivity is

1.80 - 1.50 = +0.30

, indicating a more connected network graph.

Step-by-Step Solution

1

Calculate the Phase 1 Beta index

\beta_1 = \frac{e_1}{v_1} = \frac{12}{8} = 1.50

The Beta index evaluates topological network connectivity as the ratio of edges (

e

) to vertices (

v

).

2

Determine the cumulative vertices and edges for Phase 2

v_2 = 8 + 2 = 10

vertices;

e_2 = 12 + 6 = 18

edges

Phase 2 integrates newly constructed nodes and routes into the existing Phase 1 network framework.

3

Calculate the Phase 2 Beta index

\beta_2 = \frac{e_2}{v_2} = \frac{18}{10} = 1.80

The new network ratio is computed using the updated totals of edges and vertices.

4

Calculate the net change between Phase 1 and Phase 2

\Delta \beta = \beta_2 - \beta_1 = 1.80 - 1.50 = +0.30

Subtracting the Phase 1 index from the Phase 2 index provides the net increase in connectivity.

Key Concept

Topological Network Connectivity (Beta Index)

Question 12410Question →

During chain surveying, a field surveyor needs to mark the precise endpoint of each completed chain length along a baseline on the ground. Which of the following elementary surveying tools is used specifically for this purpose?

Arrows (chaining pins)

Prismatic compass

Abney level

Offset rod

Show answer & explanation

Answer: Arrows (chaining pins)

Answer

Arrows (chaining pins) are inserted into the ground at the end of each chain length to keep accurate count of distances measured.

Arrows, also known as chaining pins, are standard chain surveying accessories made of heavy steel wire pointed at one end. They are inserted directly into the ground at the forward end of the chain to mark each completed chain length, allowing the surveyor to keep an accurate record of total distance measured.

Step-by-Step Solution

1

Identify the fieldwork task described in the stem.

The task requires marking the exact endpoint of each measured chain length on the ground during linear survey work.

Accurate distance counting in chain surveying requires temporary physical markers at every chain interval.

2

Evaluate the function of elementary surveying instruments.

Arrows (steel chaining pins) are carried by the leader surveyor and stuck into the ground at the forward handle of the chain when stretched, marking the point for tallying.

This prevents errors in counting total chain lengths and ensures continuity along the baseline.

Key Concept

Identification and primary function of elementary chain surveying accessories

Question 12411Question →

A drainage basin outlined on a topographic map with a scale of $1:50,000$ has a total stream network length of $45\text{ cm}$ and a basin area of $36\text{ cm}^2$ measured directly from the map sheet. What is the actual drainage density of the basin in $\text{km}/\text{km}^2$ ?

Show answer & explanation

Answer: 2.5

Answer

The actual drainage density of the river basin is

2.5\text{ km}/\text{km}^2

.

To calculate the true drainage density, map linear measurements and area measurements must first be converted to ground units using the scale

1:50,000

(

1\text{ cm} = 0.5\text{ km}

,

1\text{ cm}^2 = 0.25\text{ km}^2

). Total ground stream length is

45 \times 0.5 = 22.5\text{ km}

and total ground basin area is

36 \times 0.25 = 9\text{ km}^2

. Dividing stream length by basin area yields

2.5\text{ km}/\text{km}^2

.

Step-by-Step Solution

1

Convert the measured total stream network length from map units (cm) to real-world kilometers.

Ground stream length

L = 45\text{ cm} \times 0.5\text{ km/cm} = 22.5\text{ km}

.

At a scale of

1:50,000

,

1\text{ cm}

on the map represents

50,000\text{ cm} = 0.5\text{ km}

on the ground.

2

Convert the measured basin area from square centimeters to square kilometers.

Ground basin area

A = 36\text{ cm}^2 \times (0.5\text{ km})^2 = 36 \times 0.25\text{ km}^2 = 9\text{ km}^2

.

The areal scale factor is the square of the linear scale factor (

1\text{ cm}^2 = 0.25\text{ km}^2

).

3

Divide the total ground stream length by the total ground basin area.

Drainage density

D_d = \frac{22.5\text{ km}}{9\text{ km}^2} = 2.5\text{ km}/\text{km}^2

.

Drainage density measures stream channel length per unit area within a river basin.

Key Concept

Drainage Density and Scale Conversion in Basin Analysis

Estimated Time:2m 0s

Question 12412Question →

On a topographical map with a scale of $1 : 20,000$ , a proposed electric transmission line extends from Point $K$ situated on a ridge contour of $650\text{ m}$ to Point $L$ located near a stream contour of $450\text{ m}$ . If the measured distance between Point $K$ and Point $L$ on the map is $8.0\text{ cm}$ , what is the gradient of the slope between these two points?

1 \text{ in } 8

1 \text{ in } 4

1 \text{ in } 12.5

1 \text{ in } 125

Show answer & explanation

Answer: $1 \text{ in } 8$

Answer

The gradient between Point

K

and Point

L

is

1 \text{ in } 8

.

The slope gradient is calculated using the formula

\text{Gradient} = \frac{\text{Vertical Interval}}{\text{Horizontal Equivalent}}

. The Vertical Interval is

650\text{ m} - 450\text{ m} = 200\text{ m}

. The Horizontal Equivalent is calculated by multiplying the map measurement (

8.0\text{ cm}

) by the representative fraction scale factor (

20,000

), yielding

160,000\text{ cm}

, which converts to

1,600\text{ m}

. Placing these in the gradient ratio yields

\frac{200}{1,600} = \frac{1}{8}

, expressed as

1 \text{ in } 8

.

Step-by-Step Solution

1

Calculate the Vertical Interval (VI)

\text{VI} = 650\text{ m} - 450\text{ m} = 200\text{ m}

The Vertical Interval is the difference in elevation between the highest and lowest contour points.

2

Calculate the Horizontal Equivalent (HE) in ground units

\text{HE} = 8.0\text{ cm} \times 20,000 = 160,000\text{ cm} = 1,600\text{ m}

Map distance must be multiplied by the scale factor and converted into meters to match the Vertical Interval unit.

3

Compute the slope gradient ratio

\text{Gradient} = \frac{\text{VI}}{\text{HE}} = \frac{200\text{ m}}{1,600\text{ m}} = \frac{1}{8}

Gradient is expressed as the ratio of Vertical Interval to Horizontal Equivalent.

Key Concept

Slope and Gradient Calculation from Topographic Maps

Estimated Time:2m 0s

Question 12413Question →

Identify the geographical terms that complete the following description of rural settlement site selection.

Fill in the blanks below

Rural settlements located on elevated landforms such as levees, river terraces, or hilltops to avoid seasonal inundation are classified as settlements, whereas those founded in direct proximity to scarce water sources in arid environments are termed settlements.

Show answer & explanation

Answer

Settlements sited on high ground to prevent flooding are dry-point settlements, while those located close to water sources in dry environments are wet-point settlements.

Dry-point settlements are strategically built on elevated terrain to avoid flood hazards in marshy or low-lying floodplains. In contrast, wet-point settlements are established near vital water sources (such as springs, rivers, or wells) in dry or desert environments where water is scarce.

Step-by-Step Solution

1

Analyze the physical hazard described for the first blank.

Elevated landforms like river levees or terraces provide safety from floodwaters.

Selecting elevated land to escape excess water defines a dry-point site.

2

Analyze the resource constraint described for the second blank.

Arid or semi-arid regions force settlements to cluster around available water sources such as oases, springs, or wells.

Siting a settlement specifically to secure water access in dry areas defines a wet-point site.

Key Concept

Physical site factors influencing rural settlement location: Dry-point versus Wet-point sites

Estimated Time:1m 0s

Question 12414Question →

Drainage basin size is a fundamental hydrological characteristic reflecting the total land surface area drained by a river system and its tributaries. Arrange the following major African rivers in descending order of their total catchment (drainage basin) area, starting from the river with the largest basin to the one with the smallest basin.

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct sequence of rivers from largest to smallest drainage basin area is: Congo River (approx. 3.7 million km²), Niger River (approx. 2.1 million km²), Zambezi River (approx. 1.39 million km²), and Orange River (approx. 1.0 million km²).

The Congo River has the largest catchment basin in Africa (approx. 3.7 million km²), followed by the Niger River (approx. 2.1 million km²), the Zambezi River (approx. 1.39 million km²), and the Orange River (approx. 1.0 million km²).

Step-by-Step Solution

1

Determine the catchment area of the Congo River

The Congo River drains an extensive equatorial region of about 3.68–3.70 million square kilometers, making it Africa's largest catchment area.

Establishes the upper bound for African river basin areas.

2

Determine the catchment area of the Niger River

The Niger River basin spans approximately 2.11–2.12 million square kilometers across West Africa.

Ranks second largest among the selected rivers.

3

Determine the catchment area of the Zambezi River

The Zambezi River basin covers about 1.39 million square kilometers in south-central Africa.

Positions the Zambezi behind the Niger River.

4

Determine the catchment area of the Orange River

The Orange River basin covers about 0.97–1.00 million square kilometers across Southern Africa.

Identifies the smallest catchment area among the four rivers listed.

Key Concept

African River Basin Catchment Dynamics

Question 12415Question →

Which of the following is a primary characteristic of market gardening as an agricultural land-use practice?

Intensive cultivation of perishable produce located close to urban centers

Large-scale monoculture of perennial cash crops produced mainly for export

Rotational cultivation of food crops with extended land resting periods

Extensive livestock grazing across vast open grassland regions

Show answer & explanation

Answer: Intensive cultivation of perishable produce located close to urban centers

Answer

The intensive cultivation of perishable produce located close to urban centers.

Market gardening is an intensive farming system centered around growing fresh, highly perishable crops (such as leafy vegetables, tomatoes, and fruits) on small holdings close to towns and cities to ensure rapid delivery to urban consumers.

Step-by-Step Solution

1

Identify the key definition and spatial requirement of market gardening.

Market gardening involves growing high-demand, perishable food items like fresh fruits, vegetables, and flowers.

Perishable goods require rapid transport to consumers to prevent spoilage.

2

Evaluate the land-use intensity and location associated with market gardening.

It requires high labor and capital inputs per unit area and is situated adjacent to urban populations.

Proximity to urban markets reduces transportation time and costs.

Key Concept

Market Gardening and Agricultural Land Use Intensity

Question 12416Question →

Different regions across Nigeria experience distinct weather patterns influenced by geographic factors such as latitude, ocean proximity, and relief. Pair each Nigerian climatic zone on the left with its defining climatic characteristic on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

Sub-equatorial Climate Zone pairs with double rainfall maxima exceeding

2,000\text{ mm}

; Tropical Hinterland Climate Zone pairs with single rainfall peak (

1,000\text{ mm} - 1,500\text{ mm}

); Tropical Continental Climate Zone pairs with a dry season up to

7\text{ months}

and wide diurnal range; High Plateau Climate Zone pairs with temperature reduction by altitude to around

21^\circ\text{C} - 22^\circ\text{C}

.

Each Nigerian climatic zone has distinct thermal and moisture characteristics driven by latitude, distance from the Gulf of Guinea, and elevation. The Sub-equatorial coast receives double rainfall peaks and over

2,000\text{ mm}

of rain. Moving northward, the Tropical Hinterland receives

1,000\text{ mm} - 1,500\text{ mm}

with a shorter rainy season, while the Tropical Continental zone farther north experiences up to

7\text{ months}

of dry season and high diurnal temperature ranges. The High Plateau climate features reduced temperatures (

21^\circ\text{C} - 22^\circ\text{C}

) due to orographic altitude.

Step-by-Step Solution

1

Analyze coastal influences in southern Nigeria

Identify that the moist Tropical Maritime (

\text{mT}

) air mass dominates the south for most of the year, causing heavy precipitation (

>2,000\text{ mm}

) and a double rainfall peak.

This corresponds to the Sub-equatorial Climate Zone.

2

Examine the transitional central belt of Nigeria

Identify that moving inland yields moderate rainfall (

1,000\text{ mm} - 1,500\text{ mm}

) with a single peak around July/August.

This corresponds to the Tropical Hinterland Climate Zone.

3

Evaluate the far northern region affected by the Sahara Desert

Identify that the prolonged presence of dry Tropical Continental (

\text{cT}

) air causes a dry season lasting up to

7\text{ months}

and high diurnal temperature variations.

This corresponds to the Tropical Continental (Sudan) Climate Zone.

4

Determine the effect of altitude on high relief zones like Jos Plateau

Apply the lapse rate principle, noting that higher elevation significantly lowers mean temperatures relative to surrounding plains.

This corresponds to the High Plateau (Montane) Climate Zone.

Key Concept

Climatic Regions of Nigeria and their spatial characteristics

Question 12417Question →

Among the political divisions of Africa, West Africa contains three landlocked nations that lack direct access to an ocean or sea. Which of the following combinations correctly identifies all three landlocked West African countries?

Burkina Faso, Mali, and Niger

Burkina Faso, Mali, and Guinea

Niger, Chad, and Burkina Faso

Mali, Niger, and Benin

Show answer & explanation

Answer: Burkina Faso, Mali, and Niger

Answer

Burkina Faso, Mali, and Niger are the three landlocked countries situated in West Africa.

The combination listing Burkina Faso, Mali, and Niger accurately identifies the only three landlocked sovereign states in the West African sub-region. None of these three nations possess a direct maritime coastline.

Step-by-Step Solution

1

Analyze the regional geographical boundaries of West Africa.

West Africa consists of 16 countries, spanning from Mauritania in the west to Nigeria in the east.

Establishing regional boundaries narrows down the political scope to West African nations.

2

Identify countries within West Africa that have no oceanic coastline.

Mali, Burkina Faso, and Niger do not possess sea borders, relying on coastal neighbors for maritime transit.

A landlocked nation is defined by being entirely encircled by land boundaries.

3

Distinguish West African landlocked nations from neighboring regional landlocked states.

Chad is a landlocked nation located in Central Africa, while Guinea and Benin are coastal West African states.

Excluding coastal states and landlocked states of neighboring regions verifies the precise combination.

Key Concept

Landlocked States and Political Divisions of West Africa

Question 12418Question →

Match each soil conservation and management strategy implemented in Nigeria on the left with the corresponding soil degradation threat and soil type it primarily addresses on the right.

Click a left item, then click its matching right item

Show answer & explanation

Answer

The correct pairings match each regional soil conservation practice in Nigeria to its target soil type and degradation mechanism: Shelterbelts in northern states control wind erosion on loose Regosols; Gabion check dams and revegetation in Southeastern escarpments stabilize deep gully erosion on friable sandy Ferrallitic soils; Terracing and contour ridging on the Jos Plateau prevent sheet erosion on shallow highland Ferruginous soils; Dykes and drainage controls in the Niger Delta manage tidal flooding and salinization in coastal Hydromorphic soils.

Each pair correctly links a distinct Nigerian geographic region and soil conservation method with its specific soil degradation process and soil group. Shelterbelts stabilize light-textured northern Regosols against wind erosion; gabions and biological planting remediate catastrophic gully erosion in deep Southeastern sandy Ferrallitic soils; stone terracing limits sheet erosion on Jos Plateau Ferruginous soils; and coastal bunds manage flooding/salinization in Niger Delta Hydromorphic soils.

Step-by-Step Solution

1

Analyze Northern Nigerian environmental conditions and soil conservation responses.

In semi-arid states like Sokoto, Katsina, and Kano, dry harmattan winds induce wind erosion on loose, coarse-textured Regosols. Multi-row shelterbelts serve as physical barriers that reduce wind speed and retain soil moisture.

Matching shelterbelts to wind erosion control on northern sandy soils.

2

Evaluate soil degradation dynamics in Southeastern Nigeria.

Southeastern Nigeria (e.g., Agulu-Nanka in Anambra, Enugu) features deep, weakly structured sandy Ferrallitic soils on steep escarpments. High rainfall energy causes rapid gully incision, requiring mechanical structures like gabion check dams alongside deep-rooted biological cover (bamboo).

Matching escarpments and gully control structures to sandy Ferrallitic soils.

3

Examine highland slope management on the Jos Plateau.

The Jos Plateau experiences intense seasonal rainfall on sloping terrain underlain by thin Ferruginous tropical soils over crystalline basement rocks. Stone terracing and contour ridging break the slope length and slow water velocity to minimize sheetwash.

Matching highland terracing to sheet erosion control on Ferruginous soils.

4

Assess coastal soil management in the Niger Delta.

The low-lying Niger Delta consists of Hydromorphic and mangrove soils subject to daily tides, seasonal inundation, and saline intrusion. Dykes, tidal bunds, and managed drainage prevent coastal erosion and soil degradation due to excess salinity.

Matching coastal engineering controls to Hydromorphic and mangrove soil hazards.

Key Concept

Regional variation of soil degradation mechanisms and targeted soil conservation techniques across Nigerian soil zones

Estimated Time:2m 0s

Question 12419Question →

Commercial timber exploitation in African tropical rainforests follows a systematic operational procedure from resource identification to final shipment. In what chronological order do these key stages of timber extraction take place?

Drag items to arrange them in the correct order

Show answer & explanation

Answer

The correct chronological order is: 1. Cruising the forest concession block to locate, identify, and mark mature commercial hardwood trees; 2. Felling the marked trees with chainsaws and stripping off the upper crown and branches; 3. Skidding the heavy logs through temporary forest tracks to a central log landing; 4. Transporting the logs via river rafts or specialized trucks to coastal sawmills and export ports.

Commercial lumbering in African tropical rainforests begins with forest cruising to mark mature commercial trees. After marking, timber workers fell the trees and remove the crown. Tractors then skid the heavy trunks to a central forest landing, where they are loaded for final transport down river channels or roads to sawmills and seaports.

Step-by-Step Solution

1

Identify the initial pre-harvesting phase

Cruising and tree selection/marking comes first.

Commercial logging operators survey forest concessions to select specific mature hardwood species before any clearing or cutting begins.

2

Determine the harvesting action

Felling and de-limbing follows tree marking.

Trees are felled at the buttress level and stripped of branches to convert trunks into timber logs.

3

Identify short-distance haulage within the concession

Skidding logs to a central forest landing follows felling.

Individual logs scattered across the dense forest floor must be collected at a central depot using tractors.

4

Identify long-distance transport to processing or export sites

Long-distance transport via river floating or heavy trucks comes last.

Consolidated logs at the forest landing are loaded onto river rafts or logging trucks for delivery to coastal mills or ports.

Key Concept

Sequential stages of commercial hardwood extraction and transport in African tropical forests

Question 12420Question →

A morphometric analysis of a river basin provides the quantitative data shown below:

Morphometric Parameter	Value
Total Basin Surface Area ( $A$ )	$50\text{ km}^2$
Cumulative Stream Length ( $L$ )	$125\text{ km}$

Based on these hydrological parameters, what is the drainage density of the basin, and what does its magnitude imply about the basin's surface runoff response?

2.5\text{ km/km}^2

, indicating a high drainage density associated with rapid surface runoff and high flood potential.

0.4\text{ km/km}^2

, indicating a low drainage density associated with slow surface runoff and dominant groundwater recharge.

2.5\text{ km/km}^2

, indicating a low drainage density because stream channels are widely spaced over highly permeable terrain.

6,250\text{ km/km}^2

, indicating an ultra-dense drainage network resulting from extreme vertical relief mismatch.

Show answer & explanation

Answer: $2.5\text{ km/km}^2$ , indicating a high drainage density associated with rapid surface runoff and high flood potential.

Answer

The drainage density of the basin is

2.5\text{ km/km}^2

, which indicates a high drainage density characterized by rapid surface runoff and high peak flood potential.

The correct answer properly calculates drainage density (

D_d

) as the total stream length divided by basin area (

125\text{ km} / 50\text{ km}^2 = 2.5\text{ km/km}^2

). Hydrologically, a high drainage density (

2.5\text{ km/km}^2

) signifies a closely knit stream network that collects and transmits storm runoff rapidly, resulting in swift hydrological response and high flood potential.

Step-by-Step Solution

1

Identify the formula for drainage density (

D_d

).

D_d = \frac{\text{Total Cumulative Stream Length } (L)}{\text{Total Basin Surface Area } (A)}

Drainage density measures the total length of stream channels per unit area of a drainage basin.

2

Substitute the given values into the formula.

D_d = \frac{125\text{ km}}{50\text{ km}^2} = 2.5\text{ km/km}^2

Dividing

125\text{ km}

by

50\text{ km}^2

yields the linear stream length per square kilometer of basin area.

3

Interpret the hydrological significance of the calculated drainage density value.

A drainage density of

2.5\text{ km/km}^2

represents a relatively high density, implying impermeable surface rocks/soils, steep slopes, minimal infiltration, rapid runoff delivery into main channels, and high flood responsiveness.

Higher drainage density values mean precipitation reaches stream channels quickly, increasing surface runoff rates.

Key Concept

Drainage Density (

D_d

) and Basin Hydrological Response

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