Chapter 3 Book Excercise Solved on Geography of the World
Q1. What is meant by lithosphere and hydrosphere?
Answer:
- Lithosphere: The solid outer part of the earth’s surface, including continents, islands, mountains, plateaus, plains, valleys, and deserts. It covers about 29% of the earth’s surface (~149 million km²).
- Hydrosphere: The water-covered portion of the earth, including oceans, seas, rivers, lakes, and groundwater. It covers about 71% of the earth’s surface (~361 million km²). All oceans are interconnected.
→ Together, lithosphere and hydrosphere shape climate, vegetation, and human settlement.
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Q2. Describe the early stage of the earth according to the Continental Drift Theory.
Answer:
- About 300 million years ago, the earth’s lithosphere existed as a single supercontinent called Pangaea, surrounded by Panthalassa (global ocean).
- A fracture formed the Tethys Sea, dividing Pangaea into Laurasia (north) and Gondwanaland (south).
- During the Mesozoic Era (~250 million years ago), these split further and drifted, forming present continents.
→ Laurasia gave rise to North America, Greenland, Europe, and northern Asia; Gondwanaland formed South America, Africa, India, Arabia, Australia, and Antarctica.
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Q3. Describe the topography of the ocean floor.
Answer:
- Continental Shelf: Shallow submerged margin (0–200 m depth), rich in marine life.
- Continental Slope: Steeper descent beyond shelf (200–2000 m depth).
- Deep Sea Plain: Flat ocean floor (~4000 m depth).
- Oceanic Ridges and Canyons: Underwater mountain chains and valleys.
- Deep Sea Trenches: Narrow, steep depressions; Mariana Trench (11,022 m) is the deepest.
→ The ocean floor is as rugged and diverse as land surfaces.
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Q4. Write about the distribution of oceans and continents.
Answer:
- Continents (29% of earth’s surface): Asia, Africa, Europe, North America, South America, Oceania, Antarctica.
• 67% of land lies in the Northern Hemisphere → ~90% of world’s population lives there.
- Oceans (71% of earth’s surface): Pacific, Atlantic, Indian, Southern, Arctic.
• 57% of water lies in the Southern Hemisphere.
→ Pacific is the largest ocean; Arctic is the smallest.
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Q5. Write about the landforms on the land surface of the earth.
Answer:
- Mountains and Hills: Himalayas, Rockies, Andes, Alps.
- Plateaus: Tibetan Plateau (highest), Deccan Plateau, Mongolian Plateau.
- Plains and River Valleys: Ganga–Brahmaputra plains, Mississippi valley.
- Coastal Plains: Narrow lowlands along coasts (e.g., Eastern Coastal Plains of India).
- Deserts: Sahara (largest), Gobi, Thar, Atacama.
→ Landforms influence climate, vegetation, agriculture, and human settlement.
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Q6. Write about the physical characteristics of Asia.
Answer:
- Location: Largest continent (44.6 million km², ~30% of earth’s land). Lies mostly in Northern Hemisphere between 78°N–1°N latitude and 25°E–170°W longitude.
- Boundaries: North – Arctic Ocean; South – Indian Ocean; East – Pacific Ocean & Bering Strait; West – Ural Mountains, Caspian Sea, Mediterranean Sea.
- Relief: Himalayas (Everest 8,848 m), Karakoram (K2 8,611 m), Kunlun, Altai, Tienshan, Ural; Plateaus – Tibetan, Pamir, Deccan, Iranian; Deserts – Gobi, Thar, Arabian.
- Rivers: Indus, Ganga, Brahmaputra (south); Ob, Yenisei, Lena (north); Huang He, Yangtze, Amur (east); Mekong, Irawaddy, Menam (south-east).
- Lakes: Baikal, Balkhash, Chilka, Dal, Loktak.
→ Asia’s diverse relief includes fertile plains, high mountains, vast deserts, and dense population centers.
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Q7(a). Why about 90% of the world’s population lives in the Northern Hemisphere?
Answer:
- The Northern Hemisphere contains about 67% of the earth’s land area (lithosphere).
- This hemisphere has extensive fertile plains, river valleys, and temperate climates suitable for agriculture and settlement.
- Historically, major centers of civilization, trade, and industry developed here.
→ As a result, nearly 90% of the world’s population is concentrated in the Northern Hemisphere.
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Q7(b). Why does Antarctica not have any permanent human settlement?
Answer:
- Antarctica is located in the extreme south polar region, covered with thick ice throughout the year.
- The climate is extremely cold, with harsh winds and minimal vegetation.
- There is no arable land, limited freshwater availability, and scarce natural resources.
- Accessibility is difficult and living conditions are hostile.
→ Therefore, Antarctica has no permanent human settlement, only temporary scientific research stations.
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Q8(a). What is the natural boundary between Asia and Europe?
Answer: The Ural Mountain Range (and Ural River).
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Q8(b). Which is the longest mountain range in the world and where is it located?
Answer: The Andes Mountain Range, located along the western coast of South America.
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Q8(c). Which is the largest and smallest country in the world in terms of area?
Answer: Largest – Russia; Smallest – Vatican City.
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Q8(d). Which country is spread over two continents?
Answer: Russia (Europe and Asia).
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Q8(e). Which is the largest and smallest country in the world in terms of population?
Answer: Largest – China; Smallest – Vatican City.
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Q8(f). Name the major mountain range of North America and its location.
Answer: The Rocky Mountains, located in western North America (from Alaska to Mexico).
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Q8(g). Which is the largest desert in the world and where is it located?
Answer: The Sahara Desert, located in North Africa.
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Q8(h). Name two northerly and two easterly rivers of Asia.
Answer: Northerly – Ob, Yenisei (also Lena).
Easterly – Huang He (Yellow River), Yangtze (also Amur, Xi).
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Q8(i). Name one mountain range, one river and one desert of Australia.
Answer: Mountain Range – Great Dividing Range.
River – Murray River (also Darling).
Desert – Great Victoria Desert.
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Q8(j). Name three European countries located in the Mediterranean region.
Answer: Spain, Italy, Greece (also France’s southern coast, Malta, Cyprus).
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Q9(a). Write short notes on Pangaea.
Answer:
- Pangaea was a supercontinent that existed about 300 million years ago.
- It comprised all the earth’s landmasses together, surrounded by a global ocean called Panthalassa.
- Later, a fracture formed the Tethys Sea, dividing Pangaea into Laurasia (north) and Gondwanaland (south).
- These eventually split and drifted to form the present continents.
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Q9(b). Write short notes on the Arctic Ocean.
Answer:
- The Arctic Ocean is the smallest ocean in the world (~14 million km²).
- It surrounds the North Pole and is bordered by northern Asia, Europe, and North America.
- Average depth is about 3500 m.
- Due to its polar location, it remains covered with thick ice for most of the year.
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Q9(c). Write short notes on the continent of Oceania.
Answer:
- Oceania includes Australia, New Zealand, Papua New Guinea, and numerous Pacific islands.
- It is located mainly in the Southern Hemisphere.
- Australia is the largest landmass, characterized by ancient plateaus, deserts, and the Great Dividing Range.
- Oceania’s islands vary from volcanic to coral formations, with diverse climates and cultures.
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Q9(d). Write short notes on the rivers of Asia.
Answer:
- Asia has many large rivers originating from mountains and plateaus.
- South: Indus, Ganga, Brahmaputra.
- North: Ob, Yenisei, Lena.
- East: Huang He (Yellow), Yangtze, Amur.
- South-East: Mekong, Irawaddy, Menam.
- These rivers form fertile plains and deltas, supporting dense populations and agriculture.
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Q9(e). Write short notes on the lakes of Africa.
Answer:
- Africa has several large lakes, many formed in rift valleys.
- Major lakes: Victoria, Tanganyika, Malawi (Nyasa), Albert, Chad, Turkana, Kivu.
- These lakes are vital for ecosystems, transport, fisheries, and human livelihoods.
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Q9(f). Write short notes on the rivers of Europe.
Answer:
- Europe is rich in rivers that support agriculture, transport, and industry.
- Examples: Thames (UK), Seine and Rhone (France), Rhine and Elbe (Germany), Danube (Central Europe), Po (Italy), Volga, Don, Ural (Russia).
- These rivers connect major cities and have historically supported trade and civilization.
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Q9(g). Write short notes on the Appalachian Highland Region.
Answer:
- Located in eastern North America, stretching from Newfoundland to Alabama.
- It is an old, eroded mountain system with hills, valleys, and plateaus.
- Includes ranges like the Alleghany and Blue Ridge.
- Known for coal deposits and historical settlement.
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Q9(h). Write short notes on the lakes of North America.
Answer:
- North America has many large freshwater lakes.
- The Great Lakes: Superior, Michigan, Huron, Erie, Ontario.
- Other major lakes: Great Bear, Great Slave, Winnipeg, Great Salt Lake.
- These lakes are crucial for transport, fisheries, and regional economies.
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Q10(a). Difference between Continental Shelf and Continental Slope
Answer:
1. Continental Shelf is the shallow submerged margin of continents; Continental Slope is the steep descent beyond the shelf.
2. Shelf depth is up to ~200 m; Slope depth ranges from ~200 m to ~2000 m.
3. Shelf is gently sloping and wide; Slope is narrow and steep.
4. Shelf is rich in marine life, fisheries, and mineral resources; Slope has fewer resources and is less accessible.
5. Shelf is economically important for oil and gas exploration; Slope mainly acts as a transition zone to deep ocean basins.
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Q10(b). Difference between Everest and Godwin Austen (K2)
Answer:
1. Everest is the highest peak in the world (8,848 m); K2 is the second highest (8,611 m).
2. Everest is located in the Himalayas (Nepal–China border); K2 is in the Karakoram range (Pakistan–China border).
3. Everest is relatively more accessible for climbers; K2 is considered technically more difficult and dangerous.
4. Everest has more established climbing routes and facilities; K2 has fewer routes and harsher conditions.
5. Everest is more famous globally as the tallest peak; K2 is renowned among mountaineers for its extreme challenges.
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Q10(c). Difference between Oceania and Antarctica
Answer:
1. Oceania includes Australia, New Zealand, Papua New Guinea, and Pacific islands; Antarctica is a single ice-covered continent.
2. Oceania is inhabited with permanent settlements; Antarctica has no permanent human settlement.
3. Oceania has varied climates (tropical, temperate, arid); Antarctica has extreme polar climate.
4. Oceania has diverse landforms (plateaus, deserts, mountains, coral islands); Antarctica is dominated by ice sheets and glaciers.
5. Oceania supports agriculture, trade, and industry; Antarctica is used mainly for scientific research.
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Q10(d). Difference between Gobi Desert and Atacama Desert
Answer:
1. Gobi Desert is in Asia (Mongolia and northern China); Atacama Desert is in South America (Chile).
2. Gobi is a cold desert with harsh winters; Atacama is a hot desert, one of the driest places on earth.
3. Gobi has steppe-like vegetation and supports nomadic herding; Atacama has minimal vegetation due to extreme aridity.
4. Gobi’s dryness is due to continental climate and rain shadow; Atacama’s dryness is due to cold Humboldt Current and Andes rain shadow.
5. Gobi is larger in area (~1.3 million km²); Atacama is smaller (~105,000 km²) but more extreme in dryness.
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Q11(a). Which is the world’s second largest ocean?
Answer: (3) Atlantic Ocean
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Q11(b). Which is the smallest continent in the world?
Answer: (4) Oceania
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Q11(c). In which ocean are the Falkland Islands located?
Answer: (1) Atlantic Ocean
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Q11(d). Which sea separates Asia and Africa?
Answer: (2) Red Sea
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Q11(e). Which mountain range naturally separates Asia and Europe?
Answer: (1) Ural Mountain Range
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Q11(f). In which continent is Ecuador located?
Answer: (2) South America
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Q11(g). What is the capital of Brazil?
Answer: (3) Brasilia
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