GCE Geography
Past Questions

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Saturn is well known for its spectacular and prominent ring system composed of ice and rocky debris. Jupiter is the largest planet, not Mars. Saturn and Uranus have the most moons, not Venus. Mercury has virtually no atmosphere due to its weak gravitational pull.

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The Moon's gravitational pull is the primary cause of ocean tides on Earth, with the Sun's gravity playing a secondary role. The Moon takes approximately 27.3 days (not 365 days) to orbit the Earth. The Moon does not generate its own light but reflects sunlight. The Moon has no significant atmosphere and cannot support life.

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Aphelion is the point in the Earth's elliptical orbit where it is farthest from the Sun, occurring around July 4. The closest point is called perihelion, which occurs around January 3. The prefix 'ap-' means away from.

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Lagos is at 3°E, so it is east of Greenwich and therefore ahead of GMT. The time difference is 3° × 4 minutes/degree = 12 minutes. GMT is therefore 12 minutes behind Lagos time: 1:00 p.m. − 12 minutes = 12:48 p.m. This reflects the principle that places east of Greenwich keep times ahead of GMT.

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During the Northern Hemisphere summer (around June 21, the summer solstice), the Sun is directly overhead at the Tropic of Cancer (23½°N). This occurs because the Earth's axial tilt causes the Northern Hemisphere to be inclined toward the Sun at this time of year.

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The corona is the outermost layer of the Sun's atmosphere, visible as a glowing white halo during a total solar eclipse when the Moon blocks the brighter photosphere. It extends millions of kilometres into space and has extremely high temperatures exceeding one million degrees Celsius.

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The total angular difference between 75°E and 15°W is 75 + 15 = 90°. Since the Earth rotates 15° per hour, the time difference is 90 ÷ 15 = 6 hours. The town at 15°W is west of 75°E, so it is 6 hours behind, giving 12:00 − 6:00 = 06:00 hours. Wait — recalculating: 12:00 noon minus 6 hours = 06:00 hours.

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The Earth is the third planet from the Sun in our Solar System. The order is Mercury, Venus, Earth, Mars, and so on outward. This position places Earth in the habitable zone where liquid water can exist.

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The Earth's axis is tilted at 23½° from the vertical (perpendicular to the orbital plane), which means it makes an angle of 66½° with the plane of its orbit (ecliptic). This tilt is responsible for the seasons experienced on Earth.

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Intrusive igneous activity occurs when magma cools and solidifies slowly beneath the Earth's surface, forming coarse-grained rocks such as granite. The slow cooling allows large mineral crystals to develop. Extrusive activity, by contrast, involves lava cooling rapidly at the surface.

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After one half-life (500 million years), 50% of the parent isotope remains. After a second half-life (another 500 million years), 25% remains. Therefore, two half-lives have elapsed, giving a total age of 500 × 2 = 1,000 million years. This is the principle of radiometric dating used to determine absolute rock ages.

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An anticline is an upward-arching fold in which the rock strata dip away from the central axis on both sides. A syncline is the opposite — a downward trough-like fold. A horst and graben are fault-related features involving the vertical displacement of crustal blocks, not folding.

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A blowhole is formed when the roof of a sea cave collapses or is eroded through, creating a hole at the cliff top through which compressed air and water are forced upward by wave action. A stack is an isolated pillar of rock separated from a headland, while a geo is a narrow coastal inlet.

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Under intense heat and pressure, limestone is metamorphosed into marble, while shale is metamorphosed into slate. These are the correct parent rock–metamorphic rock relationships. Quartzite is the metamorphic equivalent of sandstone, not limestone or shale.

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A delta is a depositional landform that develops at the mouth of a river where it enters a standing body of water such as a sea or lake. The sudden reduction in velocity causes the river to deposit its sediment load, building up a triangular or fan-shaped plain. The Niger Delta in Nigeria is a classic example.

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Limestone is an organic sedimentary rock formed mainly from the compaction and cementation of calcium carbonate derived from the shells and skeletons of marine organisms. It is neither formed by cooling magma nor by metamorphic processes. The presence of fossils is a common characteristic of limestone.

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Concordant intrusions, such as sills and laccoliths, are emplaced parallel to the existing bedding planes or rock strata. Discordant intrusions, such as dykes and batholiths, cut across the existing rock strata at an angle. The distinction is based entirely on the geometric relationship between the intrusion and the surrounding country rock, not on composition or location.

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Karst topography develops in areas underlain by soluble rocks, particularly limestone, where carbonation weathering creates distinctive features including swallow holes (sinkholes), caves, stalactites, stalagmites, and underground drainage systems. Granite uplands and volcanic plateaus do not produce these solution features.

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Weather refers to the atmospheric conditions of a place at a particular point in time, which can change from hour to hour or day to day. Climate, on the other hand, is the average of weather conditions over a long period, usually 30 years or more.

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A barometer is the instrument specifically designed to measure atmospheric pressure. A hygrometer measures humidity, an anemometer measures wind speed, and a thermometer measures temperature.

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The ITCZ is a belt of low pressure where the North-East Trade Winds (harmattan) and South-West monsoon winds converge. Its seasonal migration northward and southward determines the onset and retreat of the rainy season across Nigeria. The harmattan originates from the Sahara, not the Atlantic Ocean.

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Convectional rainfall is most common in the rainforest belt of Nigeria. The intense solar heating causes moist air to rise rapidly, cool, condense, and produce heavy afternoon thunderstorms. Orographic rainfall occurs near mountains, and frontal rainfall is associated with temperate regions where air masses meet.

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The diurnal (daily) range of temperature is calculated by subtracting the minimum temperature from the maximum temperature. Therefore, 34°C − 18°C = 16°C. Option A is the sum, option B is the average, and option D is simply the minimum temperature.

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Using the environmental lapse rate of 6.5°C per 1000 m, the temperature decrease over 500 m = (6.5 × 500)/1000 = 3.25°C. Since temperature increases as altitude decreases, the sea-level temperature = 20°C + 3.25°C = 23.25°C. Option C incorrectly adds the full 6.5°C, and option A subtracts instead of adding.

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The sea moderates temperatures in coastal areas because water has a high specific heat capacity, meaning it heats up and cools down more slowly than land. This maritime influence reduces temperature extremes in Lagos. Kano, being far inland, experiences the full continental effect with hotter days and cooler nights, giving it a larger annual range.