100% 2017/2018 waec Geography Practical answer

8a)  *Causes of Desert Encroachment*

1. Human activities: such activities such as over-grazing, over-cultivation, bush burning, and excessive cutting of firewood greatly reduce the vegetative cover and expose the land to drought and desertification. Examples of areas with desert encroachment are the Sahelian zones of Nest Africa, Ethiopia, Somalia and Sudan.
2. Change in Weather: The frequent and prolonged dry weather increases the aridity of affected areas.
3. The southward movement of the dry sub-tropical high pressure belt results in severe drought in semi-arid regions.

b)  *Effects of Desert Encroachment*

1. Large scale disruption of socio-economic life arising from crop failure and shortage of water and pasture for livestock.
2. Widespread malnutrition and diseases such as kwashiokor and marasmus.
3. Migration of people from drought areas to more humid areas.
4. Large refugee population, that are made up of victims of drought and social insecurity in the semi-arid areas.
5. Disruption of ecological balance and loss of vegetation, soil and water resources.


c) *Preventive Measures of Desert Encroachment*

1. Conservation of existing vegetation through legislation against indiscriminate exploitation and felling of forests and trees.
2. Legislation and strong control against bush burning.
3. Improved grazing practices.
4. Establishment of shelter belts to protect the soil and arrest the effect of desertification.
5. Afforestation programs.
6. Integrated rural development.

Factors that affect Mass Movement

It is very clear, that mass movement or mass wasting is movement of weathered material with the aid of gravity, there are many factors that affect this movement. I shall tell you about 6 main factors as follows:
1. Where permeable rocks alternate with impermeable rocks, the permeable rocks are more more prone to mass wasting than the impermeable rocks.

2. Mass movement is pronounced in areas with steep slopes where the weathered layer is deep and the weathered materials are loose. Naturally, the rate of movement of weathered materials is faster on steep slopes than on gentle slopes.

3. Mass movement is encouraged if there are earthquakes and volcanic eruptions.

4. Areas with a high annual range of temperature and a high frequency of freezing and thawing will encourage soil creep while areas with a high temperature and occasional torrential rainfall encourage mudflow.

5. Mass movement is also encouraged if there is no vegetation.

6. The activities of man like mining and herding of animals encourage the production of mass movement or mass wasting. This are the factors that affect Mass movement or wasting.

6a) soil is the upper layer of earth in which plants grow, a black or dark brown material typically consisting of a mixture of organic remains, clay, and rock particles.

6i)Soil is a mixture of minerals, organic matter, gases, liquids,

6bii Clay soils with 25-40% clay
These soils have a good ability to transport water by
capillary action from deep layers but the rate is slow, so plant water requirements are not met through capillary water.

2 These soils are darker in colour and soil aggregation is more distinct.



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No4
Longitude

Longitude is defined. as the " angular measurement of a place west or east of the Prime or Greenwich Meridian 1..e Longitude ‘ 0° . It 15 used to calculate time. The longitude of a place written as “long 70°03

41” W” is read as longitude 70 degrees} minutes 41 seconds west of the Greenwich

Meridian

Characteristics of Lines of Longitllde

. Longitudes are imaginary lines on the earth’s surface. ' ' '

. Lines of longitudes are not parallels. They

converge at the poles. 13 They are often called meridians or

“midday lines”.

. i All places '1 on the same meridian have [midday, midnight, sunrise and sunset at the same time. ,

. Longitudes are measured in degrees west or east of the Greenwich Meridian. .

.gThe highest humbered longitude is 180.3”

and the lowest is 0°. ~

Longitudes run from North to South at

right angles to latitudes.

Lines of longitude are measured in

degrees east or west of the central

:32?de called the Greenwich MamieIn

3a )
Erosion is the process of eroding or being eroded
by wind ,
water, or other natural agents . While Mass
movement is
the movement of surface material caused by
gravity .
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7a )
i ) Agricultural Pollution
ii) Oil Pollution .
iii) Radioactive Substances polution
iv ) River dumping pollution
v ) Marine Dumping pollution
7b )
i ) A regular qualitative and quantitative monitoring
of fresh
water resources.
ii) Construct proper sanitary landfill
sites.
iii) Investigate ground water quality .
iv ) Provide government help for waste
management by
industries .
v ) Throw refuse into garbage cans . Visitors who
throw
garbage into pools , lakes , ponds, and even along
the
beaches pollute recreational sites on a daily basis

3b)
i)runing water
ii)winds
iii)waves
vi)glaciers

3a)
Erosion is the process of eroding or being eroded by wind, water, or other natural agents. While Mass movement is the movement of surface material caused by gravity.



6bii Clay soils with 25-40% clay
These soils have a good ability to transport water by
capillary action from deep layers but the rate is slow, so plant water requirements are not met through capillary water.

2 These soils are darker in colour and soil aggregation is more distinct.

4a)
i)Rarely has fossils
ii)React with acid
iii)have alternate bands of light
and dark minerals
4b)
i)formed through the action of heat and pressure
ii)formed from clay
iii)formed from limestone
4c)
i)rocks are source of minerals eg gold,silver,petroleum etc
ii)rocks are source of materials for construction
iii)rocks serves as raw materials for industry eg cement industry