Land and Oceans Exercise Solutions | KalviGavani

Land and Oceans — Exercise Solutions

Use this page alongside the official Samacheer Kalvi textbook. Solve every exercise question on your own first, then check the solutions below.

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I. Choose the Correct Answer (MCQs)

Q1. Which of the following is the smallest ocean on Earth?

• (a) The Pacific Ocean
• (b) The Indian Ocean
• (c) The Atlantic Ocean
• (d) The Arctic Ocean

The Arctic Ocean is the smallest and shallowest of the five oceans, located around the North Pole. It is roughly one-sixth the size of the Pacific Ocean.

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Q2. The Malacca Strait connects

• (a) The Pacific and Atlantic Oceans
• (b) The Pacific and Southern Oceans
• (c) The Pacific and Indian Oceans
• (d) The Pacific and Arctic Oceans

The Strait of Malacca is a narrow stretch of water between the Malay Peninsula and the Indonesian island of Sumatra. It connects the Pacific Ocean (through the South China Sea) and the Indian Ocean (through the Andaman Sea).

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Q3. Which of the following oceans is the busiest ocean?

• (a) The Pacific Ocean
• (b) The Atlantic Ocean
• (c) The Indian Ocean
• (d) The Arctic Ocean

The Atlantic Ocean is the busiest ocean because it connects major industrialised regions — North America and Europe — and has the most shipping routes, including the busiest shipping lane in the world.

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Q4. The frozen continent is ___

• (a) North America
• (b) Australia
• (c) Antarctica
• (d) Asia

Antarctica is called the "frozen continent" because about 98% of its surface is covered by a massive ice sheet. It is the coldest, driest, and windiest continent on Earth.

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Q5. A narrow strip of water that connects two large water bodies

• (a) A Strait
• (b) An Isthmus
• (c) An Island
• (d) A Trench

A strait is a narrow strip of water connecting two larger water bodies. Examples: Palk Strait, Strait of Malacca, Bering Strait. An isthmus, by contrast, is a narrow strip of land connecting two larger landmasses.

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Additional MCQs:

Q6. The largest continent is

• (a) Africa
• (b) North America
• (c) Europe
• (d) Asia

Asia is the largest continent, covering about 44.58 million km² — roughly 30% of Earth's total land area.

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Q7. Mount Everest is located in

• (a) India
• (b) Nepal
• (c) China
• (d) Pakistan

Mount Everest (8,848.86 metres) is the highest peak in the world, located on the border of Nepal and Tibet (China). It is part of the Himalayan mountain range.

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Q8. The longest mountain range in the world is

• (a) The Himalayas
• (b) The Alps
• (c) The Andes
• (d) The Rockies

The Andes mountain range in South America is the longest continental mountain range, stretching about 7,000 km along the western coast.

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Q9. Which is not grouped under second-order landform?

• (a) Mountains
• (b) Plateaus
• (c) Valleys
• (d) Plains

Valleys are third-order landforms (formed by erosion and deposition). Mountains, plateaus, and plains are second-order landforms.

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Q10. 'Roof of the world' denotes

• (a) Tibetan Plateau
• (b) Deccan Plateau
• (c) Indo-Gangetic Plain
• (d) Chotanagpur Plateau

The Tibetan Plateau is the highest plateau in the world, with an average elevation of about 4,500 metres. It is called the "Roof of the World" because of its extreme height.

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II. Fill in the Blanks

1. The world's largest continent is Asia.

2. Chotanagpur Plateau is the mineral-rich plateau in India.

3. The largest ocean is the Pacific Ocean.

4. Deltas are third order landforms.

5. The Island continent is Australia.

6. The highest peak in the world is Mt. Everest.

7. In the Sangam period, Mountain and its environs are classified as Kurinji land.

8. The flat-topped part of the plateau is called Table land.

9. The plains have been the cradle of civilisations from the earliest times.

10. Sand dunes form the third order landforms.

11. The process of removal of surface material is called Erosion.

12. Chain of volcanoes around the Pacific Ocean is called the Ring of Fire.

13. The shape of the Atlantic Ocean resembles the letter S.

14. Bay of Bengal and Palk Bay are connected by Palk Strait.

15. The deepest part of the ocean is called Trench.

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III. Circle the Odd One Out

Q1. Africa, Europe, Australia, Sri Lanka

Sri Lanka is an island nation (country). Africa, Europe, and Australia are continents.

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Q2. The Arctic Ocean, the Mediterranean Sea, the Indian Ocean, the Atlantic Ocean

The Mediterranean Sea is a sea (partially enclosed by land). The Arctic Ocean, Indian Ocean, and Atlantic Ocean are oceans.

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Q3. Plateau, Valley, Plain, Mountain

A valley is a third-order landform (formed by erosion/deposition). Plateau, plain, and mountain are second-order landforms.

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Q4. The Bay of Bengal, the Bering Sea, the China Sea, the Tasman Sea

The Bay of Bengal is a marginal sea of the Indian Ocean. The Bering Sea, China Sea, and Tasman Sea are all marginal seas of the Pacific Ocean.

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Q5. The Andes, the Rockies, the Everest, the Himalayas

Mount Everest is a peak (a single mountain). The Andes, Rockies, and Himalayas are mountain ranges.

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IV. Match the Following

Key trenches and their oceans: - Mariana Trench — Pacific Ocean (deepest point on Earth at ~10,994 m) - South Sandwich Trench — Southern Ocean - Milwaukee Trench — Atlantic Ocean - Java Trench — Indian Ocean - Eurasian Basin — Arctic Ocean

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V. Statement-Based Questions

Q1. Consider the following statements: 1. Plains are formed by rivers. 2. The 'South Sandwich Trench' is found in the Indian Ocean. 3. Plateaus have steep slopes.

Choose the correct answer:

• (a) 1 and 3
• (b) 2 and 3
• (c) 1, 2 and 3
• (d) 2 only

Statement 1 is correct: Plains are formed by the deposition of sediments by rivers over long periods. Statement 2 is wrong: The South Sandwich Trench is found in the Southern Ocean, not the Indian Ocean. Statement 3 is correct: Plateaus are elevated flat surfaces bounded by steep slopes on one or more sides.

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Q2. Statement I: Mountains are second-order landforms. Statement II: The Mariana Trench is the deepest trench in the world.

• (a) I is true; II is wrong
• (b) I is wrong; II is true
• (c) Both the statements are true
• (d) Statements I and II are wrong

Mountains are indeed second-order landforms (continents and oceans are first-order). The Mariana Trench in the Pacific Ocean is the deepest known point on Earth at approximately 10,994 metres below sea level.

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VI. Answer in a Word

1. Which is the highest plateau in the world? → Tibetan Plateau

2. Name a second-order landform. → Mountains, Plateaus, and Plains (any one)

3. Which ocean is named after a country? → Indian Ocean (named after India)

4. Name the islands located in the Arabian Sea. → Lakshadweep Islands and Minicoy Islands

5. What is the deepest part of the ocean called? → Trench

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VII. Short Answer Questions

Q1. What is a continent?

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Q2. Name the continents which surround the Atlantic Ocean.

• West: North America and South America
• East: Europe and Africa

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Q3. What are oceans?

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Q4. List the continents according to their size.

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Q5. Name the oceans which surround North America and South America.

North America:

• West: Pacific Ocean
• East: Atlantic Ocean
• North: Arctic Ocean

South America:

• West: Pacific Ocean
• East: Atlantic Ocean

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VIII. Distinguish Between

Q1. Distinguish between a Mountain and a Plateau.

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Q2. Distinguish between an Ocean and a Sea.

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IX. Detailed / Long Answer Questions

Q1. Explain the classification of landforms.

First-Order Landforms

• The largest landforms on Earth
• Include continents (vast landmasses) and oceans (vast water bodies)
• Formed by tectonic forces deep within the Earth
• Examples: Asia, Africa, Pacific Ocean, Atlantic Ocean

Second-Order Landforms

• Found within continents and oceans
• Include mountains, plateaus, and plains on land
• Include mountain ranges, trenches, and deep-sea plains in oceans
• Formed by tectonic forces, volcanic activity, and internal processes
• Examples: Himalayas (mountain), Deccan Plateau (plateau), Indo-Gangetic Plain (plain), Mariana Trench (ocean trench)

Third-Order Landforms

• The smallest landforms, found within second-order landforms
• Include valleys, beaches, sand dunes, waterfalls, deltas, and caves
• Formed by external processes — erosion (wearing away) and deposition (building up)
• Examples: Grand Canyon (valley), Marina Beach (beach), Sundarbans Delta (delta)

The key pattern to remember: First order = continents/oceans; Second order = mountains/plateaus/plains; Third order = valleys/beaches/dunes.

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Q2. Write a note on plateaus.

Key features of plateaus:

• Elevated flat surface at the top
• Steep slopes on one or more sides
• Formed by volcanic activity or by the erosion of surrounding land
• Can be hundreds or thousands of metres above sea level

Important plateaus of the world and India:

Types of plateaus:

• Intermontane plateaus — surrounded by mountains on all sides (e.g., Tibetan Plateau)
• Piedmont plateaus — at the foot of mountains (e.g., Patagonia Plateau)
• Continental plateaus — not surrounded by mountains (e.g., Deccan Plateau)

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Q3. Why are plains highly populated?

1. Flat terrain: Plains are flat or gently rolling lands, making them easy to build houses, roads, and infrastructure.

2. Fertile soil: Rivers flowing through plains deposit rich alluvial soil that is excellent for agriculture. The Indo-Gangetic Plain, for example, is one of the most fertile regions in the world.

3. Water availability: Rivers and groundwater provide abundant water for drinking, irrigation, and industrial use.

4. Easy transportation: The flat land allows for easy construction of roads, railways, and airports, facilitating trade and movement.

5. Suitable for agriculture: The combination of fertile soil, flat land, and water makes plains ideal for growing crops, supporting large populations.

6. Historical significance: Many ancient civilisations flourished on plains — the Indus Valley Civilisation (Indus Plain), Egyptian Civilisation (Nile Valley), and Mesopotamian Civilisation (Tigris-Euphrates Plain).

Plains are often called the "cradles of civilisation" because they provided everything early humans needed — food, water, shelter, and easy movement.

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Q4. Describe the features of the Pacific Ocean.

Size and location:

• Covers about one-third of the Earth's surface
• Bounded by Asia and Australia on the west and North and South America on the east
• Area: approximately 165.25 million km²

Key features:

• Deepest point: The Mariana Trench (approximately 10,994 metres deep) is the deepest point on Earth, located in the Pacific Ocean
• Ring of Fire: A chain of active volcanoes and earthquake zones surrounds the Pacific Ocean, forming the Pacific Ring of Fire — about 75% of the world's volcanoes are located here
• Bering Strait: Connects the Pacific Ocean to the Arctic Ocean between Russia and Alaska
• Islands: Contains thousands of islands, including the Hawaiian Islands, Fiji, and many Pacific island nations
• Currents: Major ocean currents include the North Pacific Current, South Pacific Current, Kuroshio Current, and California Current

Importance:

• Major shipping routes connecting Asia, Americas, and Oceania
• Rich in marine resources — fishing is a major economic activity
• Tsunami-generating zone due to tectonic activity along the Ring of Fire

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Q5. Explain the importance of oceans.

1. Cover most of the Earth: Oceans cover nearly ¾ (71%) of the Earth's surface, making Earth the "Blue Planet."

2. Water reservoir: Oceans hold about 97% of the Earth's water. They are the primary source of the water cycle that provides fresh water through evaporation and rainfall.

3. Oxygen production: Marine plants, especially phytoplankton, produce more than half of the atmospheric oxygen through photosynthesis.

4. Climate regulation: Oceans absorb carbon dioxide and regulate global temperatures. Warm and cold ocean currents influence the climate of coastal regions.

5. Trade and commerce: Oceans serve as major trade routes for international shipping — about 90% of global trade is carried by sea.

6. Food source: Oceans provide fish and other seafood, which are a primary protein source for billions of people.

7. Mineral resources: Oceans contain valuable minerals, oil, natural gas, and other resources extracted through offshore drilling.

8. Energy: Oceans provide renewable energy through tidal power, wave energy, and ocean thermal energy.

9. Biodiversity: Oceans are home to millions of species — from microscopic plankton to the largest animal ever (the blue whale).

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Q6. Describe the five oceans of the world.

Memory trick for size order (largest to smallest): Pacific Atlantic Indian Southern Arctic = PAISA

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Common Mistakes to Avoid

1. Confusing first, second, and third-order landforms. First order = continents and oceans. Second order = mountains, plateaus, plains. Third order = valleys, beaches, sand dunes, deltas. Do NOT classify valleys as second-order landforms.

2. Saying Australia is the smallest continent. While this is commonly stated, remember that Australia IS both a continent and a country. Do not confuse it with Greenland (the largest island, not a continent).

3. Confusing strait and isthmus. A strait is a narrow strip of water connecting two larger water bodies (e.g., Palk Strait). An isthmus is a narrow strip of land connecting two larger landmasses (e.g., Isthmus of Panama). Remember: Strait = Water, Isthmus = Land.

4. Mixing up the trenches and their oceans. Mariana Trench = Pacific Ocean (deepest). South Sandwich Trench = Southern Ocean. Milwaukee Trench = Atlantic Ocean. Java Trench = Indian Ocean. Eurasian Basin = Arctic Ocean.

5. Saying the Atlantic Ocean is the largest. The Pacific Ocean is the largest. The Atlantic is the second-largest but the busiest ocean. Size and traffic are different measures.

6. Confusing sea and ocean. A sea is smaller and partially enclosed by land (e.g., Arabian Sea, Mediterranean Sea). An ocean is vast and open (e.g., Pacific, Atlantic). Do not use them interchangeably.

7. Forgetting why plains are densely populated. The exam often asks this. Remember the four key reasons: flat terrain, fertile soil (from rivers), water availability, and easy transportation. Plains are "cradles of civilisation."

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Exam Checklist

Before your exam, make sure you can:

• [ ] List all seven continents in order of size (Asia, Africa, North America, South America, Antarctica, Europe, Australia)
• [ ] List all five oceans in order of size (Pacific, Atlantic, Indian, Southern, Arctic) — remember PAISA
• [ ] Explain the three orders of landforms with examples
• [ ] Distinguish between mountains and plateaus (comparison table)
• [ ] Distinguish between oceans and seas (comparison table)
• [ ] Explain why plains are densely populated (4-5 reasons)
• [ ] Describe the features of the Pacific Ocean (largest, deepest, Ring of Fire, Mariana Trench)
• [ ] Identify the five oceans and match trenches to their respective oceans
• [ ] Define strait, isthmus, trench, delta, and give examples
• [ ] Explain the importance of oceans (water, oxygen, climate, trade, food)
• [ ] Circle the odd one out correctly (identify categories: continent vs. island, ocean vs. sea, landform orders)
• [ ] Answer statement-based questions by verifying each statement independently
• [ ] Name the highest plateau (Tibetan), mineral-rich plateau in India (Chotanagpur), and volcanic plateau (Deccan)
• [ ] Recall that the Atlantic Ocean is S-shaped and the busiest ocean
• [ ] Remember that Australia is both a continent and a country (island continent)