CBSE Class 10 Science Sustainable Management of Natural Resources Assignment Set B

Question. Dams are bane or boon? Justify your answer.
                             OR
Give three points to justify that dams can have advantages or disadvantages.
Answer : Dams are useful in producing hydroelectricity, fishing, irrigation and tourism
If their construction is not planned properly it may lead to
(i) Economic problems (ii) Ecological problems
(iii) Social problems
Example: Tehri Dam, Tawa Dam

Question. State two reasons each of conserving 
(a) Forest and
(b) Wild life
Answer : (a) Forest: It needs to be conserved as it is a natural resource, many industries depend on it and will exploit and deplete the forest. It is biodiversity hot-spot.
(b) Wildlife: It maintains the ecological balance. Hence all animals which are hunted for skin, fur, tusk, horns etc. need protection and their habitat also need to be conserved.

Question. Why must we conserve our forests? List any two causes for deforestation taking place.
Answer :  We must conserve our forest as they are very useful.
(i) It conserves soil by preventing soil erosion, prevents flood and holds lot of water, maintain ground level of water and brings rainfall.
(ii) It provides lot of raw material for many industries like timber, sal, wood, bidi, tendu leaves, coir etc.
Two causes of deforestation:
(a) Exploitation by industries.
(b) Due to increase in population, lot of forest land is converted to build roads and dams for the infrastructure development. Pressure of human settlement is also a major cause.

Question. An environmentalist on visit to your school suggested the use of three R’s to save the environment. Explain what he meant by three R’s and how you would follow his advice at home. 
Answer : The 3R’s to save the environment means:
(i) Reduce—It means we should use less resources. The demand of exploiting
resources should be reduced by switching off lights, fans when not required, by not wasting paper, pencil etc.
(ii) Recycle—It means, to make new products from the old, used ones, e.g., recycle used paper, plastic bags, glass material and metals like tins, cans, foils etc.
(iii) Reuse—It is the best option i.e., use the things, materials again and again. e.g., use the envelope which was already used, make use of plastic bottles, jam and pickle containers etc.

Question. How do advantages of exploiting natural resources with short-term aims differ from the advantages of managing our resources with a long-term perspective? 
Answer : Exploitation of natural resources with short-term aims means exploiting it for need, money and make them extinct but using the same resources with a long-term perspective means managing the resources wisely, judiciously and using them in such a manner that they are present for future generations to come i.e., sustainable management.

Question. What is water harvesting? Write any two advantages of it. 
Answer : Water harvesting means capturing water to recharge water reservoirs.
Benefits of water harvesting:
(i) It provides water for potable use.
(ii) It provides water for irrigation.
(iii) It increases the ground water level.
(iv) It provides water for the growth of vegetation.

Question. What changes would you suggest in your home in order to be environment friendly?
Answer : Changes that I would suggest at my home in order to be environment friendly are
(i) Using a jute bag instead of plastic or polythene bag.
(ii) Switching off fans and light in the rooms which are not being used
(iii) Avoiding AC as far as possible and using fans or coolers.
(iv) Using water again and again like water after washing vegetable can be used to water the plants.
(v) Recycling clothes till they can be used for different purposes
(vi) Throwing organic and recyclable waste in separate bins

Question. What is water harvesting? Mention any two water harvesting structures.
Answer : Water harvesting means capturing rainwater where it falls or capturing the run off in a local area for future use.
Two water harvesting structures are Khadins in Rajasthan and Kulhs in Himachal Pradesh.

Question. What is a dam? Write two main advantages and two ill-effects of constructing a big dam.
Answer : Dams are massive barriers built across rivers and streams to confine and utilise the flow of water for human purposes such as irrigation and generation of electricity.
Two main advantages of constructing a big dam are:
1. Generation of electricity.
2. Irrigation.
Two ill-effects of constructing a big dam are:
1. It displaces large number of people.
2. It causes deforestation and loss of biodiversity.

Question. What is meant by sustainable management? The environmentalists are insisting upon “sustainable natural resource management”. State its four advantages.
Answer : Sustainable management is the management of natural resources which requires a longterm perspective so that they last for generations to come and are not to be exploited by the shortterm gains.
Its four advantages are as follows:
1. Resources last for a longer duration.
2. It provides steady economic growth.
3. It helps in ecological conservation.
4. It reduces pollution.

Question. Give two examples each of the following:
1. Renewable sources of energy
2. Non-renewable sources of energy.
Answer : 1. Geothermal energy, wind energy
2. Coal, petroleum

Question. How did ‘Chipko Andolan’ ultimately benefit the local people? Describe briefly.
Answer : Chipko Movement:
→ During 1970, in Reni village of Garhwal, a contractor was allowed to cut trees in a forest near the village.
→ When the contractor’s workers went to the forest to cut trees, the women of the village hugged the tree trunks to prevent the workers from cutting trees.
→ Chipko means ‘hug’ and the movement began with the villagers hugging trees. It is called the ‘Chipko Andolan’.
The movement benefited the local population as it conserved the forest products. It benefited the environment as it conserved the quality of soil and sources of water thereby, maintained balance in nature.

Question. What changes would you suggest in your home in order to be environment-friendly?
Answer : (i) All the bulbs and tube-lights should be replaced with LED (Light Emitting Diode).
(ii) At home, everyone should use natural ventilation and light on day time.
(iii) We should use cloth bags instead of plastic bags for shopping.
(iv) We should avoid wastage of water.
(v) For cooking food we should use LPG instead of microwave or oven.

Question. Can you suggest some changes in your school which would make it environment-friendly?
Answer : (i) Plant enough trees in the school.
(ii) Leaking taps should be repaired so that water is not wasted.
(iii) Bring food in reusable boxes, not in plastic bags or in aluminium foil.
(iv) Teachers can educate students about environmental conservation.
(v) There should be more windows in school for natural light.