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NSSCO Geography 6137 practice questions

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Question 1Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which layer of the Earth lies directly beneath the crust and is composed largely of solid silicate rock rich in iron and magnesium?

  1. The mantle Correct answer.
  2. The outer core
  3. The inner core
  4. The lithosphere

Explanation

The mantle is the thick silicate layer between the crust and the core, dominated by iron- and magnesium-rich minerals such as olivine. The lithosphere is a rigid outer shell that includes the crust plus the uppermost mantle, so it is not the layer directly beneath the crust in the compositional sense.

Question 2Physical Geography: Earth's structure, plate tectonics, rocks and landforms

The boundary between the crust and the mantle, marked by a sharp increase in seismic wave velocity, is known as the:

  1. Lehmann discontinuity
  2. Mohorovicic discontinuity Correct answer.
  3. Conrad discontinuity
  4. Gutenberg discontinuity

Explanation

The Mohorovicic discontinuity, or Moho, marks the base of the crust where P and S wave velocities rise sharply into denser mantle rock. It is the standard reference boundary between crust and mantle in plate tectonic studies.

Question 3Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which evidence best supports the theory that the Earth's outer core is liquid?

  1. P-waves travel faster in the mantle
  2. The crust is thinner under oceans
  3. Magnetic minerals align in basalt
  4. S-waves cannot pass through the outer core Correct answer.

Explanation

Shear waves require a rigid medium, so their disappearance beyond about 103 degrees from an earthquake epicentre shows that part of the deep interior is liquid. This seismic shadow zone is the key evidence for a liquid outer core.

Question 4Physical Geography: Earth's structure, plate tectonics, rocks and landforms

According to the theory of plate tectonics, the rigid plates of the lithosphere move because they are carried by:

  1. Convection currents in the asthenosphere Correct answer.
  2. Tidal forces from the Moon
  3. Expansion of the inner core
  4. Prevailing trade winds

Explanation

Heat from the core and mantle drives slow convection in the weak, partially molten asthenosphere, and the rigid plates ride on this moving layer. Slab pull and ridge push add to the driving forces.

Question 5Physical Geography: Earth's structure, plate tectonics, rocks and landforms

At a mid-ocean ridge, new oceanic crust is created because the boundary is:

  1. Transform, with plates sliding past
  2. Divergent, with plates moving apart Correct answer.
  3. Passive, with no relative motion
  4. Convergent, with plates colliding

Explanation

Mid-ocean ridges are divergent boundaries where upwelling magma fills the gap as plates separate, producing new basaltic crust and sea-floor spreading. Symmetrical magnetic stripes on either side record this process.

Question 6Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Deep ocean trenches and chains of volcanic island arcs are most characteristic of which plate boundary setting?

  1. Continental-continental divergent
  2. Oceanic transform
  3. Continental hotspot
  4. Oceanic-oceanic convergent Correct answer.

Explanation

Where two oceanic plates converge, the denser plate subducts, forming a trench, and rising magma builds an island arc such as the Marianas or Aleutians. Continental collision instead produces fold mountains without a trench.

Question 7Physical Geography: Earth's structure, plate tectonics, rocks and landforms

The Himalaya formed mainly because of the collision between which two plates?

  1. African and South American
  2. Indian and Eurasian Correct answer.
  3. Pacific and North American
  4. Nazca and Antarctic

Explanation

The Indian plate moved northwards and collided with the Eurasian plate, crumpling and thickening continental crust to build the Himalayan range and Tibetan Plateau. This is a continental-continental convergent boundary.

Question 8Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A chain of progressively older volcanic islands forms above a stationary mantle plume. This pattern is best explained by:

  1. Isostatic rebound of the crust
  2. Repeated subduction of ridges
  3. Plate movement over a hotspot Correct answer.
  4. Back-arc spreading behind a trench

Explanation

A hotspot stays fixed relative to the mantle while the plate moves over it, creating a line of volcanoes that become older and more eroded away from the plume. The Hawaiian-Emperor chain is the classic example.

Question 9Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Igneous rocks that solidify from lava at the surface are described as:

  1. Extrusive Correct answer.
  2. Foliated
  3. Intrusive
  4. Metamorphic

Explanation

Extrusive igneous rocks form when lava cools quickly at the surface, giving fine-grained or glassy textures such as basalt and obsidian. Intrusive rocks cool slowly underground and are coarse-grained.

Question 10Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which rock is the fine-grained, dark, mafic extrusive rock that forms most of the ocean floor?

  1. Limestone
  2. Slate
  3. Granite
  4. Basalt Correct answer.

Explanation

Basalt is a dark, fine-grained mafic volcanic rock that makes up the bulk of oceanic crust and many lava flows. Its rapid cooling at ridges produces small crystals.

Question 11Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A student finds a rock containing rounded pebbles cemented together. Which rock type and origin does this indicate?

  1. Marble, a metamorphic rock
  2. Obsidian, an extrusive igneous rock
  3. Gabbro, an intrusive igneous rock
  4. Conglomerate, a clastic sedimentary rock Correct answer.

Explanation

Rounded pebbles set in a finer matrix are the defining feature of conglomerate, a clastic sedimentary rock formed from cemented gravel. The rounding shows the fragments were transported and abraded before deposition.

Question 12Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which process turns limestone into marble?

  1. Weathering by carbonation
  2. Metamorphism under heat and pressure Correct answer.
  3. Compaction of shell fragments
  4. Rapid cooling of lava

Explanation

Marble forms when limestone is subjected to heat and pressure during metamorphism, recrystallising calcite into an interlocking mosaic. It is a non-foliated metamorphic rock.

Question 13Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which sequence correctly describes the rock cycle transformation of magma into sediment?

  1. Crystallisation, weathering and erosion, deposition Correct answer.
  2. Erosion, crystallisation, melting
  3. Deposition, melting, crystallisation
  4. Metamorphism, melting, compaction

Explanation

Magma cools and crystallises to form igneous rock, which is then broken down by weathering and eroded, with the debris deposited as sediment. Further compaction and cementation would lithify it into sedimentary rock.

Question 14Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which weathering process is most important in shaping limestone landscapes such as karst?

  1. Carbonation solution Correct answer.
  2. Frost shattering
  3. Oxidation of iron
  4. Exfoliation by heating

Explanation

Rainwater containing dissolved carbon dioxide forms weak carbonic acid, which dissolves calcium carbonate in limestone, creating features such as swallow holes, caves and pavements. This chemical process is called carbonation.

Question 15Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A river erodes a V-shaped valley mainly by:

  1. Lateral deposition in the lower course
  2. Abrasion on a floodplain
  3. Vertical erosion in the upper course Correct answer.
  4. Hydraulic action in an estuary

Explanation

In the upper course, steep gradients give the river high energy for vertical downcutting, producing steep-sided V-shaped valleys. Lateral erosion dominates further downstream where the gradient is gentler.

Question 16Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which landform is produced by glacial deposition?

  1. Moraine Correct answer.
  2. Cirque
  3. Hanging valley
  4. Arete

Explanation

Moraine is unsorted debris deposited directly by a glacier, forming ridges such as lateral and terminal moraines. The other features are erosional forms cut into bedrock.

Question 17Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which feature of a desert landscape is formed mainly by wind erosion?

  1. Playa lake
  2. Alluvial fan
  3. Yardang Correct answer.
  4. Barchan dune

Explanation

A yardang is a streamlined ridge of resistant rock sculpted by abrasion from wind-blown sand. Barchan dunes, alluvial fans and playa lakes are depositional features.

Question 18Physical Geography: Earth's structure, plate tectonics, rocks and landforms

The term 'plate margin' refers to:

  1. A zone where two lithospheric plates meet Correct answer.
  2. The centre of a plate
  3. An area of uniform rock type
  4. A line of latitude

Explanation

Plate margins are the boundaries where plates interact, and they are classified as divergent, convergent or transform. Most earthquakes and volcanoes occur along these zones.

Question 19Physical Geography: Earth's structure, plate tectonics, rocks and landforms

At a subduction zone, why does the descending plate generate magma?

  1. Friction melts the crust instantly
  2. The plate expands as pressure falls
  3. The plate melts completely as it enters the mantle
  4. Water released from the plate lowers the melting point of the mantle Correct answer.

Explanation

As the subducting plate heats, water and volatiles are released and rise into the overlying mantle wedge, lowering the melting temperature of the rock. Partial melting produces magma that feeds arc volcanoes.

Question 20Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which type of plate boundary is associated with shallow-focus earthquakes but little or no volcanism?

  1. Oceanic-oceanic convergent boundary
  2. Continental divergent boundary
  3. Continental hotspot
  4. Transform boundary Correct answer.

Explanation

Transform boundaries, such as the San Andreas Fault, involve plates sliding past each other, producing shallow earthquakes but no magma generation. Convergent and divergent boundaries typically show volcanism.

Question 21Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which statement best explains why the Pacific Ring of Fire has so many volcanoes?

  1. It lies above a single giant hotspot
  2. It is an area of thick stable continental crust
  3. It surrounds a major ocean basin with many convergent and transform margins Correct answer.
  4. It is a region of continental rifting

Explanation

The Ring of Fire follows the margins of the Pacific plate and neighbouring plates, where subduction and transform faulting generate magma and earthquakes. Convergent margins dominate, producing arc volcanoes.

Question 22Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which sedimentary rock is most likely to form from the evaporation of saline water in a desert basin?

  1. Shale
  2. Rock salt Correct answer.
  3. Coal
  4. Sandstone

Explanation

Evaporation of saline water precipitates dissolved salts, forming evaporites such as rock salt and gypsum. These are chemical sedimentary rocks typical of arid closed basins.

Question 23Physical Geography: Earth's structure, plate tectonics, rocks and landforms

An intrusive igneous rock with very large crystals most likely formed by:

  1. Rapid cooling of lava at the surface
  2. Slow cooling of magma deep underground Correct answer.
  3. Compaction of volcanic ash
  4. Recrystallisation of limestone

Explanation

Large crystals require a long time to grow, which happens when magma cools slowly at depth in a pluton. Rapid surface cooling instead gives fine-grained or glassy rocks.

Question 24Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which landform results from the collapse of a limestone cave roof?

  1. Stalactite
  2. Grike
  3. Gorge Correct answer.
  4. Doline

Explanation

When the roof of a solution cave collapses, a steep-sided gorge or collapse gorge can form. Dolines are smaller surface hollows and grikes are widened joints on a limestone pavement.

Question 25Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which factor most directly controls the rate at which chemical weathering of silicate rock occurs?

  1. Temperature and availability of water Correct answer.
  2. Latitude of the site
  3. Wind speed at the surface
  4. Thickness of the soil

Explanation

Chemical reactions such as hydrolysis proceed faster in warm, wet conditions because higher temperatures speed reactions and water supplies the medium and reactants. This is why chemical weathering is most intense in humid tropical climates.

Question 26Physical Geography: Earth's structure, plate tectonics, rocks and landforms

Which layer of Earth's interior is composed mainly of solid iron and nickel and lies above the outer core?

  1. The inner core Correct answer.
  2. The asthenosphere
  3. The lower mantle
  4. The lithosphere

Explanation

Earth's interior is divided by composition and physical state. The inner core is a solid sphere of iron-nickel alloy under enormous pressure, sitting inside the liquid outer core. The mantle and lithosphere are dominated by silicate minerals, so they cannot be the iron-nickel layer above the outer core.

Question 27Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A geologist identifies a coarse-grained rock made almost entirely of interlocking grains of the mineral olivine, with no quartz present. This rock most likely formed in which setting?

  1. At the surface, from rapidly chilled basaltic lava
  2. In a shallow marine basin, from evaporated salt water
  3. Along a river bed, from cemented sand and gravel
  4. Deep within the mantle, from slowly cooling ultramafic magma Correct answer.

Explanation

Coarse grains show that the melt cooled slowly, which points to an intrusive setting at depth. Olivine-rich rock with no quartz is ultramafic, matching magma derived from the mantle. Rapid surface cooling would instead give a fine-grained rock, and the other options describe sedimentary processes.

Question 28Physical Geography: Earth's structure, plate tectonics, rocks and landforms

At a conservative (transform) plate margin, two plates slide horizontally past each other. Which set of features is most typical of this setting?

  1. New oceanic crust forming as magma rises between plates
  2. Shallow-focus earthquakes along a fault, with little or no volcanic activity Correct answer.
  3. Crust being consumed as one plate descends beneath another
  4. Deep-focus earthquakes and explosive andesitic volcanoes

Explanation

Transform margins involve horizontal shear rather than crust creation or destruction, so rock is not melted to feed volcanoes. Friction is released as shallow earthquakes along the fault line. Subduction-related volcanism and sea-floor spreading belong to other boundary types.

Question 29Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A sedimentary rock sequence contains a lower layer of coarse conglomerate and an upper layer of fine shale. Which interpretation of the changing environment is most reasonable?

  1. Quiet deposition was followed by high-energy deposition in fast-flowing water
  2. High-energy deposition was followed by quiet deposition in deeper or stiller water Correct answer.
  3. Both layers were deposited by the same fast current at the same time
  4. The upper shale was deposited first and later pushed over the conglomerate

Explanation

Coarse sediment such as gravel needs strong currents or steep slopes to be transported and deposited. Fine mud settles only when water is calm, so the upward change from conglomerate to shale records falling energy. In an undisturbed sequence the lower bed is older, so the shale cannot have been deposited first.

Question 30Physical Geography: Earth's structure, plate tectonics, rocks and landforms

A limestone plateau develops bare rock pavements, vertical joints widened into deep clefts, and closed hollows. Which combination of processes best explains these features?

  1. Glacial plucking and abrasion beneath an ice sheet
  2. Abrasion by wind-blown sand carried across the plateau
  3. Carbonation solution along joints, together with underground drainage Correct answer.
  4. Frost shattering by repeated freeze-thaw of joint water

Explanation

Limestone is soluble in weakly acidic rainwater, so carbonation widens joints into clefts and dissolves hollows, while water drains underground rather than across the surface. This dissolution-dominated weathering is what creates karst pavements and closed depressions. Frost, wind and ice may modify the surface but do not produce the solution hollows and underground drainage.

Question 31Weather, climate and ecosystems

Which instrument is used to measure atmospheric pressure at a weather station?

  1. Rain gauge
  2. Hygrometer
  3. Barometer Correct answer.
  4. Anemometer

Explanation

A barometer measures atmospheric pressure, usually in millibars or hectopascals, and is the key instrument for identifying highs and lows on a synoptic chart. The other instruments measure humidity, wind speed and rainfall respectively.

Question 32Weather, climate and ecosystems

Air moves from a high-pressure area to a low-pressure area mainly because of differences in

  1. day length
  2. ocean salinity
  3. soil texture
  4. atmospheric pressure Correct answer.

Explanation

Wind is the horizontal movement of air along a pressure gradient, flowing from higher pressure toward lower pressure. The steeper the pressure gradient, the stronger the wind. Salinity, soil texture and day length do not drive this movement.

Question 33Weather, climate and ecosystems

Which type of rainfall occurs when moist air is forced to rise over a mountain range?

  1. Frontal rainfall
  2. Cyclonic rainfall
  3. Convectional rainfall
  4. Relief rainfall Correct answer.

Explanation

Relief (orographic) rainfall forms when moist air is forced up a slope, cools, condenses and produces rain on the windward side. The leeward side then experiences a rain shadow. Convectional and frontal rainfall are caused by heating and air-mass boundaries instead.

Question 34Weather, climate and ecosystems

The transfer of heat through a solid, such as the heating of the ground surface, is called

  1. radiation
  2. convection
  3. conduction Correct answer.
  4. evaporation

Explanation

Conduction is the transfer of heat by direct contact between particles, so it heats the ground surface and the air immediately above it. Convection moves heat through fluids, radiation travels as waves, and evaporation cools through latent heat.

Question 35Weather, climate and ecosystems

Which layer of the atmosphere contains most of the water vapour and weather systems?

  1. Mesosphere
  2. Thermosphere
  3. Stratosphere
  4. Troposphere Correct answer.

Explanation

The troposphere is the lowest atmospheric layer and holds most of the water vapour, so clouds and weather occur there. Temperature generally decreases with height in this layer. The other layers are much drier and largely weather-free.

Question 36Weather, climate and ecosystems

Which gas makes up the largest proportion of the atmosphere?

  1. Argon
  2. Carbon dioxide
  3. Nitrogen Correct answer.
  4. Oxygen

Explanation

Nitrogen accounts for roughly 78 per cent of dry air, making it the most abundant gas. Oxygen is about 21 per cent, while carbon dioxide and argon occur only in small amounts.

Question 37Weather, climate and ecosystems

In an ecosystem, organisms that make their own food using sunlight are called

  1. consumers
  2. predators
  3. decomposers
  4. producers Correct answer.

Explanation

Producers, mainly green plants, use photosynthesis to convert sunlight into chemical energy and form the base of every food chain. Consumers feed on other organisms, decomposers break down dead matter, and predators hunt prey.

Question 38Weather, climate and ecosystems

Which factor most strongly controls the temperature of a place at a given latitude?

  1. Longitude
  2. Soil colour
  3. Altitude Correct answer.
  4. Wind direction

Explanation

Temperature falls by about 6.5 degrees Celsius per 1000 metres of ascent, so altitude strongly modifies the temperature expected at a latitude. Longitude and soil colour have little direct effect, and wind direction only modifies temperature rather than controlling it.

Question 39Weather, climate and ecosystems

A weather station records a temperature of 24 degrees Celsius at sea level. Using the normal lapse rate of 6.5 degrees Celsius per 1000 metres, what is the approximate temperature at 2000 metres?

  1. 11 degrees Celsius Correct answer.
  2. 24 degrees Celsius
  3. 17 degrees Celsius
  4. 37 degrees Celsius

Explanation

The temperature falls by 6.5 degrees for every 1000 metres, so over 2000 metres it drops by 13 degrees. Subtracting 13 from 24 gives about 11 degrees Celsius.

Question 40Weather, climate and ecosystems

On a synoptic weather chart, closely spaced isobars indicate

  1. strong winds Correct answer.
  2. heavy rainfall
  3. calm conditions
  4. high humidity

Explanation

Isobars join places of equal pressure, and where they are close together the pressure gradient is steep, producing strong winds. Widely spaced isobars indicate light winds. Rainfall and humidity are not shown by isobar spacing.

Question 41Weather, climate and ecosystems

Which sequence correctly describes the water cycle from the ocean back to the ocean?

  1. Evaporation, condensation, precipitation, run-off Correct answer.
  2. Condensation, evaporation, run-off, precipitation
  3. Run-off, precipitation, evaporation, condensation
  4. Precipitation, evaporation, condensation, run-off

Explanation

Water evaporates from the ocean, condenses to form clouds, falls as precipitation, and returns to the ocean through run-off and groundwater flow. This order reflects the continuous movement of water through the cycle.

Question 42Weather, climate and ecosystems

Convectional rainfall is most likely to develop on a hot afternoon because

  1. mountains force air upwards
  2. warm and cold fronts collide
  3. cold air sinks and condenses near the ground
  4. surface heating causes moist air to rise and cool Correct answer.

Explanation

Intense surface heating makes moist air unstable, so it rises rapidly, cools and condenses into towering cumulonimbus clouds with heavy showers. This process does not depend on mountains or frontal boundaries.

Question 43Weather, climate and ecosystems

An area experiences a rain shadow. Which description best explains this?

  1. The area lies close to the equator
  2. Air rises on the leeward side and cools rapidly
  3. The windward slope receives little rainfall
  4. Air descends on the leeward side, warms and becomes dry Correct answer.

Explanation

After losing moisture on the windward slope, air descends on the leeward side, warms adiabatically and holds more moisture, so little rain falls. This creates dry conditions behind the mountain. The windward slope is the wet side, not the dry one.

Question 44Weather, climate and ecosystems

Which biome is characterised by tall trees forming a dense canopy, high rainfall and very high biodiversity?

  1. Temperate grassland
  2. Tropical rainforest Correct answer.
  3. Hot desert
  4. Tundra

Explanation

Tropical rainforests receive high rainfall throughout the year and support layered vegetation with a dense canopy and enormous biodiversity. Deserts, tundra and grasslands have far lower rainfall and simpler vegetation structures.

Question 45Weather, climate and ecosystems

Which soil process involves the downward movement of dissolved minerals through the soil profile?

  1. Erosion
  2. Weathering
  3. Leaching Correct answer.
  4. Deposition

Explanation

Leaching carries dissolved nutrients downward through the soil, often into the lower horizons, and is common in wet climates. Erosion removes soil particles, weathering breaks rock down, and deposition adds material.

Question 46Weather, climate and ecosystems

A food chain in a savanna is grass, grasshopper, lizard, hawk. Which organism is the secondary consumer?

  1. Grass
  2. Lizard Correct answer.
  3. Hawk
  4. Grasshopper

Explanation

The grass is the producer, the grasshopper is the primary consumer, and the lizard that eats the grasshopper is the secondary consumer. The hawk, which eats the lizard, is the tertiary consumer.

Question 47Weather, climate and ecosystems

Why do coastal areas usually have smaller temperature ranges than inland areas at the same latitude?

  1. Coastal areas have thinner air
  2. Coastal areas receive less sunlight
  3. Inland areas are always at higher altitude
  4. Water heats and cools more slowly than land Correct answer.

Explanation

Water has a higher specific heat capacity than land, so it warms and cools slowly and moderates coastal temperatures. Inland areas heat and cool quickly, giving them larger ranges. Sunlight, air thickness and altitude do not account for this pattern.

Question 48Weather, climate and ecosystems

Which human activity contributes most directly to the enhanced greenhouse effect?

  1. Planting trees
  2. Recycling metals
  3. Burning fossil fuels Correct answer.
  4. Building dams

Explanation

Burning fossil fuels releases large quantities of carbon dioxide, trapping more outgoing long-wave radiation and enhancing the greenhouse effect. Planting trees removes carbon dioxide, and the other activities have far smaller direct effects.

Question 49Weather, climate and ecosystems

A place has a mean annual rainfall of 800 mm and a mean annual temperature of 27 degrees Celsius with a marked dry season. Which biome is most likely?

  1. Tropical savanna Correct answer.
  2. Temperate deciduous forest
  3. Hot desert
  4. Tundra

Explanation

Warm temperatures all year with a distinct dry season and moderate rainfall fit the tropical savanna, which supports grasses and scattered trees. Tundra is too cold, deciduous forests have cooler winters, and hot deserts receive far less than 800 mm.

Question 50Weather, climate and ecosystems

A weather station at 1500 m records 12 degrees Celsius. Assuming a lapse rate of 6.5 degrees Celsius per 1000 m, what is the temperature at sea level?

  1. 18.5 degrees Celsius
  2. 12 degrees Celsius
  3. 21.75 degrees Celsius Correct answer.
  4. 2.25 degrees Celsius

Explanation

Descending 1500 metres warms the air by 6.5 multiplied by 1.5, which equals 9.75 degrees. Adding this to 12 degrees gives about 21.75 degrees Celsius at sea level.