NCERT Solutions Class 9 Social Science (Understanding Society: India and Beyond, Part II) Chapter 2 – Life on Earth
Circle of Learning • New NCERT textbook (2026-27) • In-text questions, activities and end-of-chapter questions – complete answers
The Big Questions
Answer
How do physiography and climate shape life on Earth?
Landforms, temperature and rainfall decide which plants and animals can survive in a region, creating large natural regions called biomes. For example, hot and wet conditions near the Equator support dense tropical rainforests, moderate rainfall supports grasslands, very low rainfall creates deserts, and freezing conditions with permafrost create the tundra.
Answer
How are humans and other life forms interconnected?
Biomes provide humans and other living beings with food, water, shelter and resources, while living beings also change biomes – animals pollinate and disperse seeds, microorganisms recycle nutrients and humans modify landscapes for farming and cities. Forest dwellers, for instance, depend on forests for their livelihood and also protect them.
What is the importance of preserving various life forms, and how can we contribute to their conservation?
Answer
Biodiversity keeps ecosystems healthy and balanced and supports human survival through food, medicine, clean air and water. We can contribute by protecting hotspots and protected areas, supporting community efforts like sacred groves and Joint Forest Management, practising responsible ecotourism, preventing forest fires and using resources sustainably.
Let's Map (Fig. 2.2 – World distribution of biomes)
Which type of biome is found in smaller, separate regions, and why?
Answer
The tropical rainforest biome is found in smaller, separate patches – the Amazon Basin, the Congo Basin, Southeast Asia, Central America, and parts of India such as the Andaman & Nicobar Islands and the Northeast. It needs high temperature and heavy rainfall throughout the year, and these conditions occur only in certain areas near the Equator, separated by oceans, highlands and drier regions. The temperate deciduous biome also appears in separate patches (eastern North America, Europe and eastern Asia) because moderate temperatures with distinct seasons occur only in particular mid-latitude areas.
Which continent has the least number of biomes? What could be the reason for this?
Answer
Antarctica has practically no biome shown on the map because it is almost entirely covered by thick ice and is extremely cold, so very little life can survive there. Among the inhabited continents, Australia has the fewest biomes – mostly desert and grassland with small areas of forest – because much of its interior is very dry and receives little rainfall.
Answer
Why are there areas that do not have any specific biomes?
Some areas, such as the ice sheets of Antarctica and Greenland and very high mountain regions, are left without a specific biome because they are covered by permanent ice and snow or are too cold and rocky for soil and vegetation to develop. High mountains also change conditions over short distances with altitude, so they cannot be shown as a single biome on a small world map.
Let's Explore (Layers of a rainforest)
Look at the layers of vegetation in a rainforest. What do the yellow shapes in the figure indicate?
Answer
The yellow shapes indicate the amount of sunlight reaching each layer. The emergent layer gets full sunlight (a full circle), the upper canopy gets most of it, the understory or lower canopy gets about half, and the forest floor receives very little because the dense canopy above blocks the light.
Let's Explore (Animals of the grassland)
Observe Fig. 2.5 and explore which of these animals you will find in the grasslands of India.
Answer
Fig. 2.5 shows an elephant, lions, a giraffe, a zebra and antelopes. Of these, the elephant (Indian elephant, for example in the grasslands of Kaziranga, Assam), the lion (the Asiatic lion of Gir, Gujarat) and antelopes (such as the blackbuck, chinkara and nilgai) are found in India. Giraffes and zebras do not live in the wild in India; they are found in the African savannas.
Let's Explore (Life in the desert)
What types of activities do you think people in desert regions generally undertake to sustain their households and livelihood?
Answer
People in deserts like the Thar rear animals such as camels, goats, sheep and cattle, and move with their herds in search of pasture. They grow drought-resistant crops like bajra and pulses during the short rainy season, and earn income from handicrafts (embroidery, leather and textiles), salt-making (as in the Rann of Kutch), camel transport and tourism.
With the help of your teacher, explore how do people address issues related to the availability of water.
Answer
People in deserts collect and store rainwater in traditional structures such as underground tanks (tankas/kunds), village ponds and step-wells. Women often walk long distances to fetch water in pots, as seen in Fig. 2.6. They use water very carefully, and today canals such as the Indira Gandhi Canal and piped water schemes also bring water to these areas.
Compare the physical features of the Rajasthan camel (Fig. 2.7a) and the Nubra Valley (Ladakh) camel (Fig. 2.7b).
Answer
Feature | Rajasthan camel | Nubra Valley camel |
Hump | One hump (dromedary) | Two humps (Bactrian) |
Fur | Short, thin coat | Thick, long, shaggy fur |
Body | Tall, with long legs | Shorter and stockier, with shorter legs |
Habitat | Hot, sandy Thar Desert | Cold, high-altitude desert of Ladakh |
Considering the climatic conditions, why do you think the Nubra Valley camel might have a different fur density than the Rajasthan camel?
Answer
The Nubra Valley is a cold desert where winter temperatures fall far below freezing, so the camel has thick, dense fur to keep its body warm. The Rajasthan camel lives in a hot desert, so a thin coat helps it lose body heat and stay cool. Each animal is adapted to the climate of its own desert.
Think About It (Tundra and the Himalaya)
Tundra in polar regions has mosses, lichens, shrubs, etc., while the Himalaya, in the subtropics, is dominated by conifers. What could be the reason for this? What difference do you find in the animals found in these two regions? Which species are found only in the Himalaya? Discuss in class.
Answer
Reason: The polar tundra has very long, harsh winters, short summers, weak sunlight and permafrost, so trees cannot grow and only mosses, lichens and small shrubs survive. The Himalaya lies in the subtropics, so its slopes receive stronger sunlight, more rainfall and a longer growing season; this allows coniferous forests to grow, and tundra-like alpine vegetation appears only at very high altitudes.
Animals: The tundra has reindeer, arctic foxes and polar bears, adapted to flat, frozen land. The Himalaya has mountain animals adapted to steep, rocky slopes and thin air, such as the yak, snow leopard, Himalayan tahr, musk deer, red panda and birds like the Himalayan snowcock and monal.
Species typical of the Himalaya: the Himalayan tahr, Himalayan musk deer, Himalayan monal, Himalayan snowcock and the red panda of the eastern Himalaya are not found in the polar tundra.
Let's Explore (Your local environment)
Explore your local environment. Observe how people, plants, and animals build structures and interact. Complete the table with your findings.
Answer
Sample answer (for a small town; your answer will depend on your area):
Component type | Examples observed | Interaction with humans |
Trees/Vegetation/Plants | Neem, peepal, mango, tulsi, grass | Give shade, fruit and medicine; people plant, water and sometimes cut them |
Insects | Bees, butterflies, ants, mosquitoes | Bees and butterflies pollinate crops and flowers; mosquitoes spread diseases |
Animals | Cows, dogs, sparrows, pigeons, squirrels | Provide milk and companionship; birds build nests on buildings; people feed them |
Non-living things | Soil, water, air, sunlight, rocks | Used for farming, drinking, building houses; people pollute or conserve them |
Let's Map (Biome pyramid, Fig. 2.10)
Mark the following regions at appropriate levels on Fig. 2.10: Andaman & Nicobar Islands, Keralam, Ladakh, Chhattisgarh, Odisha, Meghalaya, and Lakshadweep. Where will you place your home? There is no arrow on the third side of the triangle. What would happen if we drew an arrow? Would it point upwards or downwards?
(i) Andaman & Nicobar Islands – Tropical, wet: rainforest (7).
(ii) Keralam – Tropical, wet: rainforest (7), with tropical seasonal forest (9) in some areas.
(iii) Meghalaya – Tropical, very wet: rainforest (7).
(iv) Lakshadweep – Tropical, wet coral islands (7).
(v) Odisha – Tropical seasonal (deciduous) forest (9).
(vi) Chhattisgarh – Tropical seasonal (deciduous) forest (9).
Answer
(vii) Ladakh – A cold, dry, high-altitude region, so it goes near the top of the pyramid with tundra-like conditions (1); it is a cold desert.
Your home: place it according to your region's temperature and rainfall (sample: Delhi – tropical, dry, so scrubland/savanna (8–10)).
Third side: The left side runs from the tropical region at the bottom to the polar region at the top, so it shows increasing latitude (or altitude). If an arrow were drawn, it would point upwards, showing that as we move from the tropics towards the poles (or up a mountain) the temperature falls and the number of biomes decreases.
Let's Map (Biodiversity regions of India, Fig. 2.13)
Mark and name the following regions on the map in Fig. 2.13. Also gather more information about these biodiversity regions and discuss their features with your peers.
Answer
Region | State | Key features |
1. Namdapha National Park | Arunachal Pradesh | Tropical rainforest in the eastern Himalaya; very rich in species, including big cats like the tiger, leopard and clouded leopard, and the hoolock gibbon |
2. Rann of Kutch | Gujarat | One of the world's largest salt deserts; a marshy wetland in the monsoon; home of the Indian wild ass and flamingos |
3. Gahirmatha beach | Odisha | Coastal marine sanctuary; famous for the mass nesting of olive ridley sea turtles |
4. Gulf of Mannar | Tamil Nadu | Marine biosphere reserve between India and Sri Lanka; coral reefs, seagrass beds and the dugong |
5. Pachmarhi | Madhya Pradesh | Biosphere reserve in the Satpura range; tropical deciduous forests with sal and teak |
6. Achanakmar–Amarkantak | Chhattisgarh and Madhya Pradesh | Biosphere reserve in the Maikal hills; Amarkantak is the source of the Narmada; rich sal forests and wildlife |
Let's Explore (Thenmala Ecotourism in Keralam)
Is there any such ecotourism site in your State/UT? Collect some information and discuss with your friends.
Answer
Sample answer: Other ecotourism sites in India include Mangalajodi (Chilika Lake, Odisha), where former bird hunters now work as guides for bird-watchers; Khonoma village in Nagaland, India's first 'green village'; and Periyar Tiger Reserve in Keralam, where local people work as eco-guides and trackers. Like Thenmala, these sites protect nature, involve local communities and share tourism income with them. (Students should describe a site from their own State/UT.)
What should be a tourist's behaviour while visiting any tourist site? What should one be mindful of?
Answer
A tourist should not litter or use single-use plastic, should stay on marked trails and avoid disturbing, feeding or making noise near animals, and should not pluck plants or damage monuments. One should respect local customs and people, follow the rules of the site, save water and energy, and buy from local communities so that they benefit from tourism.
Think About It (Sacred groves)
Answer
Why are these groves so special?
Sacred groves are small forest patches protected by local communities for religious and cultural reasons, and there are over 1,00,000 of them in India, known as Devrai, Devarakadu, Kavu and Sarna. Despite their small size, they are rich biodiversity hotspots that preserve rare plants, medicinal species and wildlife, and some are linked to water sources, helping to maintain streams and groundwater.
Let's Explore (Traditional tribal livelihoods, Fig. 2.18)
Try to identify and classify the items for sale in the images given in Fig. 2.18. Also, make a list of the food and medicinal varieties available in your local market.
Answer
Items in Fig. 2.18 and their classification:
(i) Large bamboo baskets – forest-based handicrafts (made from bamboo).
(ii) Small wild fruits in baskets – forest food produce.
(iii) Roots and tubers such as ginger or turmeric – forest/farm produce with food and medicinal value.
(iv) Dried small fish – food from rivers and wetlands.
Sample list for a local market: Food – seasonal fruits (jamun, ber, mango), honey, mushrooms, millets, tamarind; Medicinal – turmeric, ginger, amla, neem, tulsi, ashwagandha.
Let's Explore (GI-tagged forest products)
Can you explain how GI tagging of the forest products mentioned above connects geography, cultural traditions, local governance, and rural economy?
Answer
(i) Geography: A GI tag links a product's special quality to the place it comes from – for example, Kandhamal Haldi gets its high curcumin content from the forest soils of Kandhamal, and Nilgiri Tea depends on the Western Ghats.
(ii) Cultural traditions: Products like Channapatna Toys, made from the 'Aale mara' tree, carry traditional skills passed down through generations.
(iii) Local governance: Producer groups, cooperatives and local bodies register and manage the GI and control the quality of the product.
(iv) Rural economy: The tag gives exclusive market recognition, prevents fake copies, fetches better prices and creates income and jobs for forest and rural communities.
Can you name some GI-tagged forest products from your state or union territory?
Answer
Sample answer: From the map in Fig. 2.19 – Ramban Sulai Honey (Jammu and Kashmir), Tezpur Litchi (Assam), Channapatna Toys (Karnataka), Kandhamal Haldi (Odisha), Erode Turmeric (Tamil Nadu), Nilgiri Tea (Tamil Nadu, Keralam, Karnataka), Tripura Queen Pineapple (Tripura) and Khasi Mandarin (Meghalaya). Students should name the products of their own State/UT using the School Bhuvan–NCERT Geoportal.
Let's Explore (Pradhan Mantri Ujjwala Yojana)
You may have heard about the Pradhan Mantri Ujjwala Yojana (PMUY). How are the benefits of this scheme impacting the health of women?
Answer
PMUY provides LPG cooking gas connections to women of poor households. Cooking with clean LPG instead of firewood reduces women's exposure to smoke and fuelwood fumes, lowering eye problems, coughs and lung diseases. It also saves the time and physical effort spent collecting firewood from forests and reduces pressure on forests.
Think About It (Wild animals in human settlements)
Which wild animals (like monkeys or deer) have you seen in your residential area? Identify the causes behind these animals' presence in human settlements.
Answer
Sample answer: Monkeys, squirrels, peacocks, nilgai, jackals and sometimes wild boars or elephants (near forests) are seen near homes. The causes are: (i) loss and fragmentation of forests due to expanding cities, roads and farms; (ii) shortage of food and water in forests; (iii) easy food from garbage, crops and people feeding animals; and (iv) roads and settlements built across traditional animal routes. Forest bridges (Fig. 2.21) and wildlife corridors help reduce such conflict and roadkill.
Let's Explore (Water tanks, Fig. 2.24)
Observe the image carefully and see if you can identify some of the tanks and mark the agricultural fields irrigated by them.
Answer
In the satellite image of Bhandara district, the tanks appear as dark or bluish-green patches, often oval or irregular, with an embankment on one side. The fields irrigated by them are the small, regular green plots lying just below (downstream of) each tank, connected to it by channels. The large number of such tanks shows how communities have used common water resources for irrigation for centuries, just like the keres of Karnataka, eri tanks of Tamil Nadu and katas of the Gond kings.
Questions and Activities
Why does India have diverse biomes? How does the local geography connect to the diversity?
Answer
India has diverse biomes because of its large size and varied geography:
(i) Latitude: India stretches from the tropical south to the northern mountains, and the Tropic of Cancer passes through its middle, giving both tropical and subtropical climates.
(ii) Relief: Altitude ranges from coastal plains to the high Himalaya, so temperature changes sharply; conifers grow on Himalayan slopes and alpine vegetation higher up.
(iii) Rainfall: Very high rainfall in the Northeast and the Western Ghats supports rainforests, moderate rainfall supports deciduous forests and grasslands, and very low rainfall creates the Thar hot desert and the cold desert of Ladakh.
(iv) Coasts and islands: A long coastline and islands support mangroves, coral reefs and marine biomes, as in the Andaman & Nicobar Islands, Lakshadweep and the Gulf of Mannar.
Because local landforms and climate differ so much, India has many biomes and biodiversity hotspots like the Himalaya, Western Ghats, North–East India and the Andaman & Nicobar Islands.
Make a list of economically valuable native plants in your region and comment on their abundance.
Answer
Sample answer (central India):
Plant | Economic use | Abundance |
Mahua | Flowers for food and oil; seeds sold | Fairly common, but old trees are declining |
Tendu | Leaves used to roll bidis | Common in forests |
Sal | Timber, seeds, leaves for plates | Common in protected forests |
Bamboo | Baskets, construction, crafts | Abundant but over-harvested in places |
Neem | Medicine, pesticide, timber | Very common |
Ashwagandha | Medicinal herb | Becoming rare in the wild; now cultivated |
Comment: Commonly used plants remain abundant where communities harvest them carefully, but some medicinal herbs and old trees are declining because of over-collection and forest loss.
Prepare a map of your state or Union Territory showing national parks and sanctuaries.
Answer
Steps: Take an outline map of your State/UT, mark district boundaries, and show national parks and wildlife sanctuaries with different symbols and a legend; use the School Bhuvan–NCERT Geoportal for locations.
Sample for Rajasthan: Ranthambore National Park (Sawai Madhopur), Sariska Tiger Reserve (Alwar), Keoladeo National Park (Bharatpur), Desert National Park (Jaisalmer–Barmer), Mount Abu Wildlife Sanctuary (Sirohi) and Kumbhalgarh Wildlife Sanctuary (Rajsamand).
Study the impact of forest fires on people dependent on forests. Try to include the causes, losses, and preventive measures.
Answer
(i) Causes: Natural causes include very high temperatures, dry leaves and lightning, made worse by climate change. Human causes include careless campfires and cigarettes, burning to clear land, and setting fire to the forest floor while collecting produce. About 36% of India's forest cover is prone to fires, of which nearly 4% is extremely prone.
(ii) Losses: Forest dwellers lose firewood, fodder, honey, bamboo, medicinal plants and other forest produce, and so their income. Homes, livestock and crops may be burnt, wildlife is killed, smoke harms health, and burnt slopes suffer soil erosion and landslides.
(iii) Preventive measures: Clearing dry litter and making fire lines, not leaving fires unattended, early detection through watchtowers and satellite alerts (fire locations can be seen on the School Bhuvan–NCERT Geoportal), training village fire-fighting groups, and involving communities through Joint Forest Management.
Answer
Why are forests often called the 'lungs of the Earth'?
Just as lungs help us breathe, forests absorb carbon dioxide and release oxygen through photosynthesis, which helps maintain oxygen levels in the air. They also store large amounts of carbon and help balance the Earth's climate, which is why they are called the 'lungs of the Earth'.
If large forest areas continue to be destroyed, what do you think would be its long-term effect on the global climate?
(i) Less carbon dioxide would be absorbed and the carbon stored in trees would be released, increasing greenhouse gases and causing global warming.
(ii) Rainfall patterns would change, as forests release moisture into the air; droughts in some areas and floods in others would become more common.
(iii) Rising temperatures would melt glaciers and raise sea levels, threatening coastal regions.
(iv) Soil erosion, landslides and desertification would increase.
(v) Loss of habitats would cause many species to disappear, weakening the balance of nature.
Answer
Discuss some traditional forest conservation methods with your grandparents or an elderly person.
Answer
Sample points from such a discussion:
(i) Sacred groves (Devrai, Kavu, Sarna) where no tree is cut.
(ii) Worship of trees like peepal, banyan and tulsi, which protects them.
(iii) Rituals to honour forest deities before collecting resources, as practised by the Gonds and Bhils.
(iv) Collecting only fallen wood and taking only as much as is needed; not harvesting during flowering or breeding seasons.
(v) Community rules on grazing and tree-cutting, like the Bishnoi tradition of protecting khejri trees and blackbuck.
These customs show that respect for nature was part of everyday life.
How do forest dwellers contribute to the protection and conservation of forests?
Answer
(i) Knowledge holders: They have traditional knowledge of herbs and forest resources, passed down through generations, which helps conserve biodiversity.
(ii) Forest protection movements: The Bishnoi Movement in Rajasthan led by Amrita Devi, and the Chipko Movement in Uttarakhand, where village women hugged trees to prevent deforestation.
(iii) Community forest management: In Mendha Lekha (Gadchiroli, Maharashtra), the Gond villagers protect 1,800 hectares of forest by regulating tree cutting, preventing fires and harvesting bamboo sustainably, deciding everything through the Gram Sabha.
(iv) Sacred groves and rituals that limit the use of forest resources.
(v) Participation in Joint Forest Management and eco-restoration.
Thus, forest dwellers act as guardians of both the ecology and the culture of forests.
What is a forest fire? Prepare a plan for prevention and mitigation of forest fires.
Answer
A forest fire is an uncontrolled fire that spreads quickly through dense vegetation, destroying trees, wildlife, homes and resources. It can be caused by natural factors and climate change, but most fires are caused by human activities.
Prevention: (i) Awareness campaigns against careless use of fire; (ii) clearing dry leaves and making fire lines before the dry season; (iii) banning burning of crop waste and the forest floor near forests; (iv) controlled, supervised burning where needed.
Preparedness: (v) Watchtowers, satellite fire alerts and mobile warnings; (vi) trained village fire-fighting volunteers with beaters, water tanks and fire extinguishers.
Mitigation and response: (vii) Quick reporting to the forest department; (viii) safe evacuation of people and livestock; (ix) replanting native species and restoring soil after the fire, with compensation and support for affected families.
Extra Important Questions
Multiple Choice Questions
Which biome has permanently frozen soil called permafrost?
Answer
(a) Desert (b) Taiga (c) Tundra (d) Grassland
Answer: (c) Tundra
2. The Rann of Kutch is one of the world's largest
(a) Cold deserts (b) Salt deserts (c) Rainforests (d) Coral reefs
Answer: (b) Salt deserts
India's first planned ecotourism destination, Thenmala, is located in:
Answer
(a) Keralam (b) Karnataka (c) Assam (d) Uttarakhand
Answer: (a) Keralam
Which village became the first in India to gain rights over its forest resources under the Forest Rights Act, 2006?
Answer
(a) Khonoma (b) Mendha Lekha (c) Thenmala (d) Gahirmatha
Answer: (b) Mendha Lekha
5. Kandhamal Haldi, a GI-tagged forest product, belongs to
(a) Tamil Nadu (b) Assam (c) Odisha (d) Meghalaya
Answer: (c) Odisha
6. Taiga biome forests consist mainly of
(a) Broad-leaved trees (b) Pines, spruces and larches (c) Cacti (d) Mosses and lichens
Answer: (b) Pines, spruces and larches
Short Answer Questions
Answer
What is a biome? How is it different from an ecosystem?
A biome is a large natural region of the world where certain types of plants and animals live under similar climatic conditions, such as tundra, desert, forest or grassland. A biome is like a broad environmental region, while an ecosystem is like a neighbourhood within it, where plants, animals and non-living things interact closely.
Answer
Why are tropical rainforests called a 'gene bank'?
Tropical rainforests, found between the Tropic of Cancer and the Tropic of Capricorn, are the world's richest storehouse of biodiversity. They preserve unique genetic material of countless species, which supports conservation and scientific research, so they are called a 'gene bank'.
What is a Geographical Indication (GI) tag? Give one example of a GI-tagged forest product.
Answer
A GI tag is a type of intellectual property right that identifies a product as coming from a specific place, whose quality or reputation is linked to that place. Example: Channapatna Toys of Karnataka, made from the wood of Wrightia tinctoria ('Aale mara').
Answer
What are ecological commons? Why are they shrinking?
Ecological commons are natural resources like forests, rivers, lakes, grazing lands, air and biodiversity that are shared and used collectively by a community, not owned by any single person. They are shrinking or degrading because of population growth, industrial use and privatisation.
Long Answer Questions
Explain the geographical aspects of biodiversity conservation.
Answer
Since biodiversity is unevenly spread across the Earth, geography plays a key role in conserving it:
(i) Hotspots of biodiversity: Regions like the Himalaya, the Western Ghats, North–East India and the Andaman & Nicobar Islands have unique species found nowhere else, so protecting them is a priority.
(ii) Ecosystem-based conservation: Strategies must suit the biome, for example mangrove protection along coasts and afforestation in mountains.
(iii) Protected areas: National parks, wildlife sanctuaries, biosphere reserves and World Heritage Sites are chosen on the basis of geography to protect critical habitats and prevent fragmentation.
(iv) Barriers and corridors: Rivers, mountains and valleys can block or guide animal movement and gene flow, so planners create wildlife corridors.
(v) Human–environment interaction: Sustainable practices differ with geography, such as terrace farming in hills and agroforestry in plains.
Thus, the survival of species depends on their location, habitat conditions and human activity in those regions.
Describe the challenges faced by people living in forests and the steps taken by the government to support them.
Answer
Challenges:
(i) Poor access to healthcare, education and clean water; women suffer from fuelwood fumes.
(ii) Restrictions on forest use, deforestation and commercial exploitation limit their access to forest produce, causing economic insecurity.
(iii) Natural disasters such as floods, landslides and forest fires.
(iv) Human–wildlife conflict, with crops damaged by elephants, monkeys and wild boars.
(v) Discrimination and low prices for their forest products.
Government steps:
(i) The Forest Rights Act, 2006 recognises their rights over traditionally used forest land and minor forest produce such as bamboo, honey and medicinal plants.
(ii) Joint Forest Management involves communities in protecting forests while sharing benefits.
(iii) PESA, DAJGUA and PM JANMAN promote tribal welfare, along with scholarships, healthcare and skill development schemes.