CBSE Class 9 Social Science Chapter 02 Shaping Of The Earths Surface MCQs Set 02

Answer: (B) Continental plates carry continents while oceanic plates carry ocean floors

Explanation:
The chapter groups tectonic plates into continental, oceanic, and mixed types based on what surface features they carry. Continental plates support landmasses, while oceanic plates lie beneath the seas.

Answer: (C) They form fold mountains, such as the Himalaya

Explanation:
When two continental plates collide, neither sinks easily since both are equally thick and light, so the crust buckles upward into fold mountains like the Himalaya. This differs from an oceanic-continental collision, where the denser oceanic plate slides underneath instead.

Answer: (B) Plant roots growing into rock cracks and splitting them apart

Explanation:
Biological weathering happens when living things, such as plants or micro-organisms, break rocks apart. Roots wedging into cracks and prying them open is the exact example the chapter gives.

Answer: (A) Continued bank erosion and sediment deposition gradually cut off a river loop

Explanation:
• A river erodes the outer bank of a bend while depositing material on the inner bank.
• Over time this widens the loop of the meander.
• Eventually the river cuts a shorter path and isolates the loop as a standing body of water called an oxbow lake.

Answer: (C) They act as natural barriers that reduce the force of waves and coastal erosion

Explanation:
Beyond tourism and fishing, beaches cushion the shoreline against powerful waves, which helps protect settlements built close to the sea.

Answer: (B) Rivers forming deltas provide navigable routes linking inland regions to the sea

Explanation:
Because the rivers that build deltas remain navigable, they let goods and people travel between the interior and the coast, which is why dense settlements and trading activity often cluster around delta regions despite the flood risk.

Answer: (B) Till

Explanation:
This deposited material is called till, and when it accumulates it forms moraines such as lateral, terminal, or medial types.

Answer: (A) Heavy snowfall on weak layers combined with sudden warming or strong wind

Explanation:
• Heavy snow builds up quickly on already weak or loosely bonded snow layers.
• Sudden warming can melt snow slightly and reduce friction holding it together.
• Strong winds may pile snow unevenly, creating fragile sections.
• Any of these, or a disturbance like an earthquake or human activity, can set an avalanche off.

Answer: (C) Prolonged drought, loose dry soil, and sparse vegetation

Explanation:
Dry, drought-affected soil with little plant cover is easily lifted by strong winds, which is why desert and semi-arid regions experience dust storms most often.

Answer: (B) A river's meandering course being used for irrigation

Explanation:
It is cited alongside the discussion of meanders as a practical case of humans using a river's flow for irrigation purposes.

Answer: (C) Cutting a hillside into level or gently sloping steps to check erosion

Explanation:
Terracing reshapes a slope into a series of flat or gently sloping steps, which slows down water flow and holds soil in place, unlike bunding or contour trenching, which use embankments and trenches instead.

Answer: (B) To slow down, hold, and let rainwater soak into a hillside

Explanation:
A CCT is dug along the contour lines of a slope so that rainwater is slowed down and given time to infiltrate, which both curbs soil erosion and recharges groundwater.

Answer: (A) Crust, mantle, core

Explanation:
• The crust is the thin outer layer on which we live.
• Below it lies the thick, hot mantle.
• The core, innermost and extremely hot and heavy, lies at the centre.

Answer: (A) Iron and nickel

Explanation:
The chapter describes the outer core as a fluid layer consisting mainly of iron and nickel, distinguishing it from the solid, spinning inner core.

Answer: (A) The wearing down, transport, and deposit of material that levels or smooths the surface over time

Explanation:
Gradation is used in the chapter to describe how forces such as running water, wind, glaciers, and waves gradually smooth the Earth's surface by lowering high areas and filling low ones.

Answer: (A) Wind wears away softer rock faster than the surrounding harder rock, leaving ridges standing

Explanation:
Yardangs form because wind erosion strips away weaker rock more quickly than harder rock, leaving behind the tougher material as streamlined ridges.

Answer: (A) Fjord

Explanation:
A fjord results when seawater fills a glacially carved valley, unlike a cirque (a bowl-shaped hollow), an arete (a sharp ridge), or a moraine (deposited glacial debris).

Answer: (A) When a smaller glacier meets a larger one, leaving its own valley floor higher up

Explanation:
Hanging valleys occur where a tributary glacier joins a larger one; because the smaller glacier erodes less deeply, its valley is left sitting above the main valley floor.

Answer: (A) The force of the falling water can be harnessed to generate hydroelectric power

Explanation:
The chapter notes that the energy of falling water at a waterfall can be used to produce electricity, in addition to drawing tourists for trekking and photography.

Answer: (A) A flat surface left behind once wind has blown away the finer particles

Explanation:
Desert pavements are one of several wind-erosion landforms mentioned in the chapter, formed when finer material is removed, leaving a flat, stony surface behind.

Answer: (A) Wind clears away loose sand until it exposes the underlying water table, allowing vegetation to grow

Explanation:
As shown with the deflation hollow, wind removes loose sand down to the level of the water table, and the resulting moisture supports plant growth, creating an oasis.

Answer: (A) Chemical weathering and erosion caused by underground water dissolving soluble rock

Explanation:
Underground water dissolves rocks like limestone through chemical action, gradually producing caves, sinkholes, stalactites, and stalagmites.

Answer: (A) Shaking of the Earth

Explanation:
The chapter's note on early Indian understanding of earthquakes explains that 'bhukampa' translates directly to the shaking of the Earth.

Answer: (A) Earth's surface is continuously reshaped by internal forces like plate movement and external forces like weathering, together producing landforms that affect human life

Explanation:
From plate tectonics to rivers, wind, and glaciers, the chapter repeatedly links internal and external forces to the landforms they create and to their impact on human settlement and livelihood.

Answer: (A) Wind erosion

Explanation:
Wind erosion is described as common in dry and sandy areas, unlike glacial erosion (moving ice), coastal erosion (sea waves), or water erosion (rivers and rain).