Extra 30 short questions and answers from the chapter:14 "Natural Resources" for Class 9 Science (CBSE):-
1. What are natural resources?
✅ Answer: Natural resources are materials or substances found in nature that are used by living organisms for survival and development. Examples include air, water, soil, minerals, and sunlight.
2. What are renewable and non-renewable resources?
✅ Answer:
Renewable resources:
Resources that can be replenished naturally, e.g., solar energy, wind energy.
Non-renewable resources:
Resources that take millions of years to form and cannot be replaced once exhausted, e.g., coal, petroleum.
3. What is the atmosphere? Name its layers.
✅ Answer: The atmosphere is the layer of gases surrounding the Earth. Layers:
Troposphere
(weather occurs here)
Stratosphere
(contains ozone layer)
Mesosphere
(burns meteors)
Thermosphere
(satellites orbit here)
Exosphere
(outermost layer)
4. Why is the ozone layer important?
✅ Answer: The ozone layer absorbs harmful ultraviolet (UV) radiation from the sun, preventing skin cancer and other health problems in living beings.
5. What causes ozone layer depletion?
✅ Answer: Ozone depletion is caused by Chlorofluorocarbons (CFCs) released from refrigerators, air conditioners, and aerosol sprays.
6. What is the greenhouse effect?
✅ Answer: The greenhouse effect is the trapping of heat by greenhouse gases like CO₂, methane, water vapor, and nitrous oxide, which keeps Earth warm and habitable.
7. What is global warming? List two causes.
✅ Answer: Global warming is the increase in Earth's average temperature due to excess greenhouse gases. Causes:
Burning fossil fuels (coal, petroleum).
Deforestation, reducing CO₂ absorption.
8. What are the effects of global warming?
✅ Answer:
Rising sea levels due to melting ice caps.
Extreme weather conditions like hurricanes and droughts.
Loss of biodiversity and habitat destruction.
9. What are the sources of atmospheric pollution?
✅ Answer:
Natural sources
– Volcanic eruptions, dust storms, forest fires.
Human activities
– Industrial emissions, vehicle exhaust, deforestation.
10. How can air pollution be reduced?
✅ Answer:
Use public transport and electric vehicles.
Reduce industrial emissions by using filters.
Plant more trees to absorb CO₂.
11. What is the hydrological cycle?
✅ Answer: The hydrological cycle (water cycle) is the continuous movement of water between land, atmosphere, and oceans through evaporation, condensation, precipitation, and collection.
12. What are the major sources of freshwater?
✅ Answer:
Rivers and lakes
Groundwater (wells and borewells)
Glaciers and ice caps
13. What is water pollution? Mention two causes.
✅ Answer: Water pollution occurs when harmful substances contaminate water bodies. Causes:
Industrial waste and chemicals.
Domestic sewage and plastic waste.
14. What is the water table?
✅ Answer: The water table is the upper level of groundwater, below which soil and rocks are completely saturated with water.
15. How can we conserve water?
✅ Answer:
Rainwater harvesting
– Collecting and storing rainwater.
Drip irrigation
– Using water efficiently for farming.
Preventing wastage
– Fixing leaks and using water judiciously.
16. What is soil erosion? Mention two causes.
✅ Answer: Soil erosion is the removal of topsoil by wind, water, or human activities. Causes:
Deforestation – Loss of plant roots holding soil.
Overgrazing – Exposes soil to wind and water erosion.
17. How can soil erosion be prevented?
✅ Answer:
Afforestation
– Planting trees to hold soil.
Terracing and contour
ploughing
– Reducing water runoff on slopes
.
18. What is humus? Why is it important?
✅ Answer: Humus is decayed organic matter in soil that improves soil fertility, retains moisture, and provides nutrients to plants.
19. What are biodegradable and non-biodegradable wastes?
✅ Answer:
Biodegradable waste
– Decomposes naturally (e.g., food scraps, paper).
Non-biodegradable waste
– Does not decompose easily (e.g., plastic, glass).
20. What are the effects of deforestation?
✅ Answer:
Loss of biodiversity and habitat destruction.
Increase in CO₂ levels, leading to global warming.
Reduced rainfall and desertification.
21. What is sustainable development?
✅ Answer: Sustainable development meets present needs without compromising the ability of future generations to meet their needs.
22. What are fossil fuels? Give examples.
✅ Answer: Fossil fuels are non-renewable energy sources formed from decayed plants and animals over millions of years. Examples: Coal, petroleum, natural gas.
23. How can we reduce the consumption of fossil fuels?
✅ Answer:
Use renewable energy sources like solar and wind energy.
Promote public transport and energy-efficient appliances.
24. What is afforestation? How does it help?
✅ Answer: Afforestation is planting trees in barren areas. It helps by:
Preventing soil erosion.
Absorbing CO₂ and reducing air pollution.
Increasing rainfall and biodiversity.
25. What is desertification? What causes it?
✅ Answer: Desertification is the conversion of fertile land into desert due to deforestation, overgrazing, and poor agricultural practices.
26. What are the effects of mining on the environment?
✅ Answer:
Deforestation and habitat destruction.
Air and water pollution due to toxic chemicals.
Soil erosion and loss of arable land.
27. What are the advantages of using renewable energy?
✅ Answer:
No pollution (clean energy source).
Unlimited availability (sun, wind, water).
Reduces dependence on fossil fuels.
28. What is rainwater harvesting? How does it help?
✅ Answer: Rainwater harvesting is collecting and storing rainwater for later use. It helps by:
Recharging groundwater levels.
Reducing water scarcity.
29. Why should we reduce plastic usage?
✅ Answer: Plastics are non-biodegradable and cause:
Water and soil pollution.
Harm to marine life.
Clogging of drainage systems.
30. What is biodiversity? Why is it important?
✅ Answer: Biodiversity refers to variety of life forms on Earth. It is important for:
Ecological balance and stability.
Providing food, medicine, and raw materials.
