NCERT Solutions Class 9 Social Science (Understanding Society: India and Beyond, Part II) Chapter 1 – Oceans and Life
Circle of Learning • New NCERT textbook (2026-27) • In-text questions, activities and end-of-chapter questions – complete answers
The Big Questions
Answer
What is the importance of ocean relief?
Ocean relief (submarine relief) is the set of landforms on the ocean floor, such as the continental shelf, continental slope, abyssal plain, mid-ocean ridge, trenches, seamounts and guyots. These features decide where the water is shallow or deep, which in turn affects marine life, the availability of resources like fish, oil and gas, the movement of ocean water, navigation and undersea exploration.
Answer
How does ocean water movement impact life and environment?
Waves shape coastlines by erosion and deposition, tides help navigation, fishing and tidal energy, and currents carry heat and influence the climate of coastal regions. These movements also spread nutrients and support marine life, while extreme forms such as storm waves and tsunamis can cause great destruction.
Answer
Why are maritime zones important for a country?
Maritime zones defined under UNCLOS tell a country how far its control and rights extend into the sea. They allow it to make laws in its territorial sea, check customs and illegal immigration in the contiguous zone and use resources like fish, oil and gas in its Exclusive Economic Zone, while avoiding conflicts with other countries.
Answer
How can we use ocean resources in a sustainable way?
We can follow the idea of the Blue Economy – using ocean resources for growth and jobs while keeping marine ecosystems healthy. This means reducing marine pollution, regulating fishing, protecting and conserving marine areas, tackling ocean acidification and following international rules such as MARPOL, as listed under SDG 14 (Life Below Water).
How do early warning systems help protect people from tsunamis and cyclones?
Answer
Early warning systems use seismic stations, ocean bottom pressure recorders, tide gauges, buoys, radars and satellites to detect a hazard, confirm it, track it and warn people in time. Alerts sent through SMS, satellite networks and display boards give coastal communities time to evacuate, which greatly reduces the loss of human and animal lives.
Let's Explore (Looking at Fig. 1.2 – Submarine relief)
How do you think these oceanic features would have been formed?
Answer
Most ocean floor features are formed by the movement of the Earth's crust and by volcanic activity. The mid-ocean ridge is formed by volcanic activity where molten magma rises and builds an underwater mountain range, and the rift valley lies along its centre. Trenches form where one part of the ocean floor sinks deep below another. Seamounts and volcanic islands are built by underwater volcanoes, and guyots are seamounts whose tops were flattened by wave action and later submerged. The continental shelf is simply the submerged edge of a continent.
Answer
Which part of the ocean floor appears deep and shallow?
The continental shelf, the submerged edge of the continent close to the coast, is the shallowest part. The ocean floor becomes deeper along the continental slope and continental rise, the abyssal plain is vast, flat and deep, and the trenches are the deepest parts of the ocean (the Mariana Trench is the deepest place on Earth).
How do you think these underwater features would have an effect on marine life and ocean movements?
Answer
The shallow continental shelf receives sunlight, so plankton and fish are plentiful there and it becomes rich in marine life. Ridges, seamounts and the shape of ocean basins act like barriers that change the direction of ocean currents and can push nutrient-rich water upward, while the deep abyssal plains and trenches have very cold, dark water where only specially adapted organisms survive.
Let's Explore (Famous sea beaches)
Find out the names of some famous sea beaches in our country and locate them on the map of India.
Answer
Sample answer (locate these on an outline map of India):
Beach | State/UT | Coast |
Marina Beach, Chennai | Tamil Nadu | East coast (Bay of Bengal) |
Puri Beach | Odisha | East coast |
Digha Beach | West Bengal | East coast |
Ramakrishna (RK) Beach, Visakhapatnam | Andhra Pradesh | East coast |
Kovalam Beach | Keralam | West coast (Arabian Sea) |
Calangute and Baga Beaches | Goa | West coast |
Juhu Beach, Mumbai | Maharashtra | West coast |
Radhanagar Beach | Andaman & Nicobar Islands | Bay of Bengal islands |
Think About It (Ocean currents and coastal temperature)
Observe the map carefully and note the movement patterns of cold and warm currents. Do you think these currents affect the temperature of nearby coastal regions?
Answer
Yes. Warm currents generally flow from the equator towards the poles and cold currents from polar regions towards the equator, and they raise or lower the temperature of nearby coasts. For example, the warm Gulf Stream keeps the waters near Norway relatively warm, so sea ice does not form easily even at 60°–70° latitude, while the cold Labrador Current along the east coast of Canada carries freezing water and supports sea ice and icebergs even at lower latitudes.
Let's Explore (Ocean currents along India's coastline)
Observe Fig. 1.9 and take a note on ocean currents along the coastline of India. What is the nature of ocean currents?
Answer
The currents near India lie in the warm tropical waters of the northern Indian Ocean, so they are warm currents. Further south the map shows the warm Equatorial Counter Current and South Equatorial Current. A special feature of the northern Indian Ocean is that its currents change direction with the monsoon winds: they generally flow clockwise during the summer (south-west) monsoon and anticlockwise during the winter (north-east) monsoon.
Let's Explore (Simeulue and traditional knowledge)
Talk to your elders and find out whether similar folk traditions or stories related to natural disasters exist in your culture. Share these with your classmates and discuss how traditional knowledge can help communities stay safe.
Answer
Sample answer: Many communities in India have such knowledge. In 2004, several indigenous communities of the Andaman & Nicobar Islands are reported to have moved to higher ground after noticing the sea suddenly drawing back, a warning sign remembered from their elders' stories. Elders in many villages also say that unusual animal behaviour, a sudden change in the colour of the sky or the sea, or a strange silence of birds signal a coming storm or flood.
Traditional knowledge helps because (i) warning signs are easy to remember through stories and songs, (ii) it works even where there is no phone network or electricity, and (iii) people react immediately without waiting for instructions, as the residents of Simeulue did. Combined with modern early warning systems, it makes communities much safer.
Think About It (Responding to an alert)
If you receive a tsunami or cyclone alert on your phone right now, do you know the five steps your family should take to stay safe?
(i) Stay calm and confirm the alert from official sources such as IMD, INCOIS or the district administration; do not spread rumours.
(ii) Keep an emergency kit ready – drinking water, dry food, medicines, torch, important documents and a charged phone.
(iii) Follow evacuation orders at once – move inland or to higher ground for a tsunami, and to a strong building or cyclone shelter for a cyclone.
(iv) Before leaving, switch off electricity and gas, secure loose objects, and help elderly people, children and persons with disabilities.
(v) Keep listening to official updates and return home only after the authorities announce that it is safe.
Answer
Let's Explore (Maritime disputes)
Can you find out some countries that have conflicts over their territorial sea waters?
Answer
Some examples of maritime disputes are:
(i) China and several Southeast Asian countries such as the Philippines, Vietnam and Malaysia over islands and waters in the South China Sea.
(ii) China and Japan over the Senkaku (Diaoyu) Islands in the East China Sea.
(iii) Greece and Turkey over waters and airspace in the Aegean Sea.
(iv) India and Pakistan over the Sir Creek area and the sea boundary off Gujarat.
(v) India and Bangladesh had a dispute over their sea boundary in the Bay of Bengal, which was settled peacefully by an international tribunal under UNCLOS in 2014 – an example of how maritime law helps resolve disputes.
Questions and activities
How do different features of the ocean floor affect human activities such as fishing, transport, and underwater exploration?
Answer
(i) Fishing: The continental shelf is shallow (0–200 m), receives sunlight and is rich in marine life, so most fishing is done there by coastal fishing communities. Seamounts also attract fish. The shelf also holds oil and gas, which are extracted offshore.
(ii) Transport: Ships must know the water depth before entering ports or narrow channels. Shallow areas, as in the Singapore Strait, force very large ships (VLCCs) to wait for high tide to avoid running aground. Flat abyssal plains are useful for laying undersea cables.
(iii) Underwater exploration: Deep trenches like the Mariana Trench and the long Mid-Ocean Ridge are difficult and expensive to explore and need special technology. Bathymetry, the mapping of the underwater surface, helps scientists study these features, find minerals and plan safe routes.
Thus, knowledge of ocean relief makes fishing more productive, navigation safer and exploration better planned.
How do waves, tides, and ocean currents influence climate, marine life, and human activities around the world?
Answer
(i) Waves: Waves, mainly caused by winds, carry energy over long distances and act as 'coastal architects', creating caves, arches, sea stacks and stumps by erosion, and beaches by deposition. Storm waves and tsunamis can damage coasts badly.
(ii) Tides: High tides allow ships to enter harbours and pass through shallow channels, and bring fish closer to the shore, helping fishing communities. The rise and fall of water can generate tidal energy, for example in the Gulf of Kutch, the Gulf of Khambhat and the Sundarbans. Tidal currents can reach 5–6 knots.
(iii) Currents: Warm and cold currents carry heat and change the climate of coastal areas – the Gulf Stream keeps Norway's waters ice-free, while the Labrador Current brings icebergs to lower latitudes. Where warm and cold currents meet, the water is rich in nutrients and forms important fishing grounds.
Together, these movements regulate climate, spread nutrients for marine life and support fishing, navigation and energy production.
Describe the importance of marine resources.
Answer
Marine resources are materials and features of the oceans that have intrinsic or economic value. They are divided into living resources (fish, marine organisms, vegetation) and non-living resources (minerals and energy). Their importance:
(i) Food and livelihood: Fish are a major source of protein, and fishing and aquaculture support millions of people.
(ii) Energy: Offshore oil and natural gas, and renewable 'blue energy' from tides, waves, currents and ocean thermal energy.
(iii) Minerals and materials: Sand, gravel and deep-sea minerals.
(iv) Trade and tourism: About 90% of global trade by volume is carried by sea, and coastal tourism is a multi-billion dollar industry.
(v) Environment: Oceans support biodiversity and unique ecosystems like coral reefs.
(vi) Culture: The śhaṅkha (conch) and kapardikā (cowrie shells), once used as currency, are linked to the Samudra Manthana story.
For a country with a long coastline like India, these resources are the bedrock of local economies, so they must be used sustainably.
Draw a poster that encourages people to protect marine resources. Include a slogan (like Save Our Seas or Fish for the Future) and explain your message in 2–3 sentences.
Answer
Sample answer:
Poster idea: A blue ocean with healthy fish and a coral reef on one half, and plastic bottles and nets choking a turtle on the other half.
Slogan: "Blue Ocean, Bright Future – Save Our Seas!"
Message: Our oceans give us food, jobs, energy and the air we breathe, but plastic waste, oil spills and overfishing are destroying marine life. Let us reduce plastic use, never throw waste on beaches and support responsible fishing so that the sea can feed future generations too.
Using a map of India, mark at least five coastal states that might need tsunami warnings.
Answer
Mark any five of these on an outline map of India: Tamil Nadu, Andhra Pradesh, Keralam, Odisha, West Bengal, Gujarat, Maharashtra, Goa and Karnataka. The Union Territories of Andaman & Nicobar Islands, Puducherry and Lakshadweep also need warnings. The 2004 Indian Ocean tsunami particularly affected Tamil Nadu, Puducherry, Andhra Pradesh, Keralam and the Andaman & Nicobar Islands, so these deserve special attention.
Work in a group and act out what would happen when a cyclone warning is issued. Highlight what role different people, like scientists, officials, and coastal villagers, would play.
Answer
Sample role-play outline:
(i) Scientists (IMD and INCOIS): Track the cyclone with satellites and radars, forecast its path, wind speed and storm surge, and issue warnings, including SSEWS storm-surge forecasts.
(ii) Government officials (district administration, disaster management authority): Receive the warning, use the Decision Support System, announce evacuation, open cyclone shelters (built under NCRMP), and deploy rescue teams, police and health workers.
(iii) Fishermen: Receive alerts on GEMINI devices and mobile phones, return to the shore and do not go to sea.
(iv) Coastal villagers: Listen to announcements, pack emergency kits, move to shelters, and help the elderly and children.
(v) Media and volunteers: Spread accurate information and stop rumours.
The play should end with the cyclone passing safely because everyone acted in time.
Suppose a foreign ship is sailing through India's territorial sea. What principle allows the ship to pass through these waters, subject to certain conditions?
Answer
The principle of Innocent Passage allows a foreign ship to pass through India's territorial sea, as long as it does not threaten India's peace, good order or security. The ship must move continuously without stopping, except in emergencies or breakdowns, and it cannot carry out fishing, military operations or any other non-peaceful activity.
A country has an Exclusive Economic Zone (EEZ) extending up to 200 nautical miles from its baseline. What rights does the country have over the natural resources in this zone?
Answer
Under UNCLOS, the country has special rights to explore and use the natural resources of its EEZ, such as fish, oil and natural gas, and to manage and conserve them. However, it does not fully own or control the waters, so ships of other countries can still pass through peacefully.
Create a model of an ocean with ship routes, protected zones, and safety measures. Based on the model, explain how it follows maritime laws and protects the ocean.
Answer
Sample model and explanation:
(i) Coast and zones: Show a coastline with a baseline, and mark the territorial sea (12 nautical miles), contiguous zone (24 nautical miles), EEZ (200 nautical miles) and the high seas beyond, as in Fig. 1.20.
(ii) Ship routes: Mark separate lanes for incoming and outgoing ships, with lighthouses and buoys, to follow COLREGs and avoid collisions. Foreign ships cross the territorial sea only by innocent passage.
(iii) Protected zones: Mark a coral reef and a breeding area for fish as no-fishing marine protected areas.
(iv) Safety measures: Add tsunami detection buoys, tide gauges, a warning centre and cyclone shelters on the coast.
(v) Pollution control: Show waste reception facilities at the port to follow MARPOL.
Explanation: The model follows UNCLOS by respecting maritime zones, COLREGs by organising traffic and MARPOL by preventing pollution. Protected zones conserve marine life, and early warning systems protect people, so the ocean stays safe, clean and open for trade.
Extra Important Questions
Multiple Choice Questions
Which is the deepest place on Earth?
Answer
(a) Mid-Ocean Ridge (b) Mariana Trench (c) Abyssal Plain (d) Gulf of Khambhat
Answer: (b) Mariana Trench
2. Spring tides occur on
(a) First-quarter moon days (b) Third-quarter moon days (c) Full moon and new moon days (d) Only during cyclones
Answer: (c) Full moon and new moon days
3. One nautical mile is equal to exactly
(a) 1,000 metres (b) 1,609 metres (c) 1,852 metres (d) 2,000 metres
Answer: (c) 1,852 metres
4. The contiguous zone extends from the baseline up to
(a) 12 nautical miles (b) 24 nautical miles (c) 100 nautical miles (d) 200 nautical miles
Answer: (b) 24 nautical miles
The GEMINI device used by fishermen receives data from which satellite system?
Answer
(a) GAGAN (b) GPS only (c) INSAT (d) Bhuvan
Answer: (a) GAGAN
Which international convention aims to reduce pollution from ships?
Answer
(a) COLREGs (b) UNCLOS (c) MARPOL (d) SDG 14
Answer: (c) MARPOL
Short Answer Questions
Distinguish between spring tides and neap tides.
Answer
Spring tides occur on full moon and new moon days when the Sun, the Earth and the Moon are in a straight line; their combined pull causes unusually high high-tides and unusually low low-tides. Neap tides occur during the first- and third-quarter moon, when the pulls of the Sun and the Moon act in different directions, so the difference between high and low tide becomes smaller.
Answer
Why is tidal information important for ports and ships?
Tidal ranges in some ports reach 4–5 metres, and about 12 metres in the Gulf of Khambhat, so a ship must check water depth and tidal range before berthing, especially at low tide. In shallow channels like the Singapore Strait, large ships such as VLCCs wait for high tide so that they do not run aground.
Answer
What is the Blue Economy?
The World Bank defines the Blue Economy as the sustainable use of ocean resources to promote economic growth, improved livelihoods and jobs while preserving the health of the marine ecosystem. It is linked to SDG 14 (Life Below Water), which aims to reduce marine pollution, regulate fishing and conserve marine areas.
What are the high seas? Mention one challenge related to them.
Answer
The high seas are the international waters lying beyond the EEZs of all countries, covering about 64 per cent of the world's oceans; they belong to no single country and are part of the global commons. Since no country controls them, problems such as overfishing, illegal fishing and conflicts over resources arise, and the laws of the flag state apply to ships there.
Long Answer Questions
Describe the different maritime zones of a country as defined by international law.
Answer
(i) Internal waters: Waters on the landward side of the baseline, under the full control of the country.
(ii) Territorial sea: Up to 12 nautical miles from the baseline. The country has near-complete control and can make laws on customs, immigration and pollution, subject to the right of innocent passage for foreign ships.
(iii) Contiguous zone: Up to 24 nautical miles from the baseline, where the country has limited control over customs, fiscal matters and illegal immigration.
(iv) Exclusive Economic Zone (EEZ): Up to 200 nautical miles from the baseline, defined under UNCLOS. The country has special rights to use resources like fish, oil and gas, but does not fully own the waters, and foreign ships may pass peacefully.
(v) High seas: Beyond all EEZs, about 64% of the oceans. They are global commons where all countries have equal rights of navigation, fishing, overflight, laying undersea cables and exploring for minerals.
These zones help countries use the sea fairly and avoid disputes.
Explain how the tsunami early warning system works in India.
Answer
After the 2004 Indian Ocean tsunami, which claimed around 2,30,000 lives, India set up the Indian Tsunami Early Warning Centre (ITEWC). The system works in four stages:
(i) Detection: A network of seismic stations detects undersea earthquakes in real time.
(ii) Confirmation: Ocean Bottom Pressure Recorders and tsunami detection buoys on the seafloor sense the passage of tsunami waves and confirm the threat.
(iii) Tracking: Coastal tide gauges and radars monitor changes in sea level to track the arrival and movement of the waves.
(iv) Warning dissemination: ITEWC alerts the Government of India, which informs state governments and emergency teams; alerts also reach officials and the public through satellite networks, SMS, emails and coastal display boards.
Technology alone is not enough, so public awareness and training programmes teach officials and coastal communities how to interpret warnings and respond quickly, saving lives.