2021 NECO GEOGRAPHY ANSWERS

GEOGRAPHY OBJ
01-10: CCEADCBCCB
11-20: DEDADCADED
21-30: EDCDCCDCBC
31-40: CEABCDCCBA
41-50: CBDBBBCBEA
51-60: CDACAABABB

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(2ai)
Great circle:
Great circle is any line that divides the earth into equal halves or hemisphere. The centre of the Great circle is also the centre of the earth. The shortest distance between any two points on the earth ‘s surface lies along the circumference of the great circle which passes these points.

(2aii)
International date line:
International date line is where the date changes by exactly one day or 24 hours when it is crossed. There is a difference of one whole day or 24hours on both sides of longitude 180°. The 180° meridian represents a date line. The international date line is not straight for it avoids cutting across islands to prevent confusion in days and dates in the tiny islands.

(2aiii)
Time zone:
Time zone is the division of the world into twenty four time zone, each of which differ from the next zone by 15° in longitude or 1hour in time. The local time of the central meridian for each zone is applied to that zone which is called a time zone. All places located on the same time zone have the same time.

(2aiv)
Prime meridian:
prime meridian is the line of 0° longitude, the starting point for measuring distance both east and west around the Earth. The prime meridian is arbitrary, meaning it could be chosen to be anywhere. The prime meridian separates the eastern hemisphere from the western hemisphere.

(2b)
TABULATE
-Parallels-
(i)Parallels are lines of latitudes
(ii)Parallels are drawn from west to east
(iii)Parallels never meet
(iv)Parallels have different lengths

-Meridians-
(i)Meridians are lines of longitude
(ii)Meridians are drawn from north to south
(iii)Meridians meet at the poles
(iv)Meridians have equal length

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(3a)
(i)Mechanically formed sedimentary rocks: They are derived from sediments of pre existing rocks. The rock debris are usually deposited by agents of erosions such as water,wind or glacier.The deposited materials are pressed together to become solid by the weight of overlying deposits. This process of solidification is called compaction or cementation. They may form conglomerates
Examples are sandstone,breccia and shale.

(ii)Organic formed sedimentary rocks: These are rocks formed from the remains of living organisms. When sedimentary rocks are formed from the remains of animals like corals or shellfish, such rocks are called Calcareous rocks.
Examples: limestone and chalk . But when sedimentary rocks are formed from the remains of vegetable matter such as a swamps and forest,they are called carbonaceous rock. Examples: Coal, lignite and petroleum.

(iii)Chemically formed sedimentary rocks: These are rocks formed from precipitation. They are also formed from other rock solution or certain minerals from solution of salt. They are often referred to as evaporators. They are also formed from crystallization.
Examples includes Potash,sodium chloride(common salt) and nitrate

(3b)
-(pick any four)-
(i)sedimentary rocks are stratified. They show distinct layers or strata.
(ii)They are non- crystalline
(iii)They may be coarse or fine grained depending on the nature of minerals deposited.
(iv)They are fossilized rocks. That is,they contain fossils of plants and animals.
(v)They are usually sold.
(vi)They are not resistant to erosion.
(vii)They are permeable.

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(4a)
(i)Temperature
(ii)Rainfall(precipitation)

(4b)
MERIT
-(Pick any three)-
(i)It is very simple to understand
(ii)It is objective
(iii)It is commonly used in teaching at various levels of educational institutions
(iv)It is quantitative because numerical values are used for defining boundaries of climatic groups

-DEMERIT-
(i)It did not consider the climate of highlands
(ii)letters used are too many and confusing
(iii)There is no clear distinction of one climate from another

(4ci)
A = Tropical rainy climate

(4cii)
Aw = Tropical Grassland of savanna Distribution

(4ciii)
C = Warm temperature rainy climate (Humid mesothermal climates )

(4civ)
E = Polar climates (Ice climate)

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(7a) The ozone layer is a natural layer of gas in the upper atmosphere that protects humans and other living things from harmful ultraviolet (UV) radiation from the sun.

(7b)
(i) Help to reduce temperature: Consequently, decreased ozone in the stratosphere results in lower temperatures.

(ii) Protection from harmful ultra violet rays and radiation: The ozone layer protects us from harmful UV rays that can have serious effects on biodiversity, animals and people’s health, including skin cancer and eye cataract.

(iii) Absorption of pollutants: The stratospheric layer which occupy the lower part of the atmosphere removes the unwanted pollutants from the earth’s surface.

(7c)(pick 2)
(i) Unregulated Rocket Launches
(ii) Chlorofluorocarbons
(iii) Volcanic eruptions
(iv) Nitrogenous Compounds

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(8a)
Geographical data refers to data and information that has explicit or implicit association with a location relative to Earth.

(8bi)
Vector data file: These data are created by digitizing the base data. They store information in x, y coordinates. Vectors models are used to store data, which have discrete boundaries like country borders, land parcels and roads. Vector models are useful for storing data that has discrete boundaries, such as country borders, land parcels, and streets.

(8bii)
Raster Data file: Raster data stores information of features in cell-based manner. Satellite images, photogrammetry and scanned maps are all raster-based data. Raster models are used to store data, which varies continuously as in aerial photography, a satellite image or elevation values

(8biii)
Geographic database: Geographic databases can store more complex elements needed to describe the world and the roads or buildings built upon it. The basic data element is the point that is the combination of the longitude, latitude, and sometimes the altitude.

(8biv)
Multi temporal data; These are data generally used for change detection. It attaches a time component to information

(8ci)
(i)Topo maps
(ii)Aerial photographs
(iii)Satellite images

(8cii)
(i)It helps to analyze urban growth and the direction of expansion.
(ii)It plays a vital for conserving natural resources and protecting the environment
(iii)It plays an essential role in planning, organizing, and decision making in the banking industry

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