Extra 20 important long questions and answers from the chapter:14 "Natural Resources" for Class 9 Science (CBSE):-
1. What are the major components of the atmosphere? Explain their significance.
✅ Answer:
The atmosphere is a mixture of gases that surround Earth. Components and significance:
Nitrogen (78%)
– Essential for plant growth (part of the nitrogen cycle).
Oxygen (21%)
– Required for respiration in living organisms.
Carbon dioxide (0.03%)
– Absorbed by plants for photosynthesis.
Water vapor (0-4%)
– Influences weather and rainfall.
Argon and other gases
– Play a minor role in atmospheric processes.
Ozone
– Absorbs harmful UV radiation from the sun.
2. What is air pollution? Mention its causes and effects.
✅ Answer:
Air pollution is the contamination of air due to harmful substances. Causes:
Industrial emissions
– Release of harmful gases from factories.
Vehicular emissions
– Carbon monoxide and nitrogen oxides from vehicles.
Deforestation
– Reduces oxygen levels and increases CO₂.
Burning fossil fuels
– Releases pollutants like sulfur dioxide.
Agricultural activities
– Pesticides and fertilizers cause air pollution.
Effects
– Causes respiratory diseases, acid rain, and global warming.
3. What is the greenhouse effect? How does it affect climate?
✅ Answer:
The greenhouse effect occurs when gases like CO₂, methane, and water vapor trap heat in the Earth's atmosphere. Effects:
Increase in global temperature
– Causes global warming.
Melting of glaciers
– Leads to rising sea levels.
Extreme weather
– More frequent floods, droughts, and hurricanes.
Disruption of ecosystems
– Coral bleaching and habitat destruction.
Food shortages
– Climate change affects agriculture.
Health issues
– Increases heat-related diseases.
4. What are ozone layer depletion and its effects?
✅ Answer:
Ozone layer depletion occurs due to the release of chlorofluorocarbons (CFCs). Effects:
Increased UV radiation
– Leads to skin cancer and cataracts.
Reduced crop yield
– UV rays damage plants.
Affects marine life
– Kills plankton, affecting the food chain.
Weakens immune system
– Increases vulnerability to diseases.
Climate change
– Disrupts weather patterns.
Prevention
– Use ozone-friendly alternatives and reduce CFCs.
5. Describe the water cycle with a diagram.
✅ Answer:
The water cycle involves the continuous movement of water through evaporation, condensation, precipitation, and collection.
Evaporation
– Water from oceans, lakes, and rivers turns into vapor.
Condensation
– Water vapor cools and forms clouds.
Precipitation
– Water falls as rain, snow, or hail.
Infiltration
– Water seeps into the ground, recharging groundwater.
Runoff
– Excess water flows back into rivers and oceans.
Importance
– Maintains ecological balance and supports life.
6. What is water pollution? Mention its causes and effects.
✅ Answer:
Water pollution occurs when harmful substances contaminate water bodies. Causes:
Industrial waste
– Factories release chemicals into rivers.
Domestic sewage
– Household waste pollutes lakes and ponds.
Pesticides and fertilizers
– Runoff contaminates groundwater.
Plastic waste
– Blocks drains and harms aquatic life.
Oil spills
– Affects marine ecosystems.
Effects
– Causes diseases, kills aquatic life, and reduces drinking water availability.
7. What is soil erosion? Mention its causes and prevention.
✅ Answer:
Soil erosion is the removal of topsoil due to natural or human activities. Causes:
Deforestation
– Trees hold soil; cutting them leads to erosion.
Overgrazing
– Livestock eats plants, leaving soil exposed.
Heavy rainfall
– Washes away fertile soil.
Unscientific farming
– Plowing removes soil cover.
Strong winds
– Blows away loose soil.
Prevention
– Afforestation, terracing, and contour plowing.
8. What are fossil fuels? Mention their disadvantages.
✅ Answer:
Fossil fuels (coal, petroleum, and natural gas) are energy sources formed from decomposed organisms. Disadvantages:
Non-renewable
– Limited supply, takes millions of years to form.
Air pollution
– Releases harmful gases (SO₂, CO₂).
Global warming
– Increases greenhouse gas levels.
Health hazards
– Causes respiratory diseases.
Acid rain
– Sulfur and nitrogen oxides mix with rain.
Mining hazards
– Coal mining causes land degradation.
9. What is rainwater harvesting? How does it help?
✅ Answer:
Rainwater harvesting is the collection and storage of rainwater for future use. Advantages:
Recharges groundwater
– Prevents water scarcity.
Reduces soil erosion
– Less water runoff.
Prevents urban flooding
– Stores excess rainwater.
Saves energy
– Reduces the need for water pumping.
Provides water in dry areas
– Useful in drought-prone regions.
Sustainable water use
– Reduces dependence on municipal supply.
10. What is biodiversity? Why is it important?
✅ Answer:
Biodiversity refers to the variety of life forms in an ecosystem. Importance:
Maintains ecosystem balance
– Supports food chains and habitats.
Medicinal value
– Many plants provide life-saving drugs.
Economic value
– Agriculture, tourism, and industries depend on biodiversity.
Pollination and oxygen supply
– Bees pollinate crops, trees give oxygen.
Prevents climate change
– Forests absorb CO₂.
Conserving biodiversity
– Wildlife sanctuaries and afforestation help.
11. What are the effects of deforestation?
✅ Answer:
Loss of biodiversity
– Habitat destruction for animals and plants.
Increase in CO₂ levels
– Leads to global warming.
Soil erosion
– Trees prevent soil loss.
Decrease in rainfall
– Fewer trees reduce water retention.
Disruption of food chains
– Animals lose their habitat.
Floods and droughts
– Trees regulate water flow.
12. What is eutrophication? Mention its causes and effects.
✅ Answer:
Eutrophication is the excessive growth of algae in water bodies due to high nutrient levels, mainly nitrates and phosphates.
Causes:
Agricultural runoff
– Fertilizers wash into rivers and lakes.
Sewage discharge
– Wastewater adds nutrients to water bodies.
Industrial waste
– Contains phosphorus and nitrogen compounds.
Detergents
– Phosphate-based detergents pollute water.
Effects:
Algal bloom
– Excess algae block sunlight.
Oxygen depletion
– Decomposing algae consume oxygen, harming aquatic life.
Loss of biodiversity
– Fish and other aquatic organisms die.
Water toxicity
– Some algae release toxins, making water unsafe.
Disrupts the ecosystem
– Affects the balance of aquatic food chains.
Control measures
– Reduce fertilizer use, treat sewage before discharge.
13. How does deforestation affect the environment?
✅ Answer:
Deforestation is the large-scale clearing of trees for agriculture, urbanization, or industrial use.
Effects:
Loss of biodiversity
– Destroys animal and plant habitats.
Increased CO₂ levels
– Fewer trees absorb carbon dioxide, worsening global warming.
Soil erosion
– Roots hold soil; without them, erosion increases.
Changes in rainfall patterns
– Reduces rainfall, leading to desertification.
Disruption of water cycle
– Less transpiration reduces cloud formation.
Preventive measures
– Afforestation, reforestation, and conservation policies.
14. What is acid rain? Mention its causes and effects.
✅ Answer:
Acid rain occurs when sulphur dioxide (SO₂) and nitrogen oxides (NOₓ) mix with water vapor and fall as acidic precipitation.
Causes:
Burning fossil fuels
– Coal and petrol release SO₂ and NOₓ.
Industrial emissions
– Factories release pollutants into the air.
Vehicle exhaust
– Cars emit nitrogen oxides.
Volcanic eruptions
– Release
sulphur
compounds.
Effects:
Damages plants and trees
– Acid rain affects leaves and soil.
Harms aquatic life
– Lowers water pH, killing fish.
Erodes buildings and monuments
– Affects limestone structures (e.g., Taj Mahal).
Causes respiratory diseases
– Irritates lungs and causes asthma.
Soil degradation
– Reduces soil fertility.
Prevention
– Use cleaner fuels, install filters in industries.
15. What are the benefits of afforestation?
✅ Answer:
Afforestation is the process of planting trees in barren lands to restore ecosystems.
Benefits:
Reduces global warming
– Trees absorb CO₂, reducing greenhouse gases.
Prevents soil erosion
– Roots hold the soil in place.
Increases rainfall
– More trees improve transpiration and cloud formation.
Restores biodiversity
– Provides habitat for animals and birds.
Enhances air quality
– Trees absorb pollutants and release oxygen.
Boosts economy
– Forest-based industries benefit from timber and medicinal plants.
16. What are the effects of industrialization on natural resources?
✅ Answer:
Industrialization has led to the overexploitation and pollution of natural resources.
Effects:
Deforestation
– Factories need land, leading to habitat destruction.
Air pollution
– Industrial emissions release CO₂, SO₂, and other gases.
Water pollution
– Chemicals from industries contaminate rivers and lakes.
Soil degradation
– Mining and waste disposal reduce soil fertility.
Resource depletion
– Excessive use of fossil fuels and minerals.
Control measures
– Implement pollution control laws, use cleaner technology.
17. How does excessive use of fertilizers and pesticides affect the environment?
✅ Answer:
Overuse of chemical fertilizers and pesticides harms the environment in several ways.
Effects:
Soil pollution
– Reduces soil fertility by killing beneficial microbes.
Water pollution
– Runoff into rivers leads to eutrophication.
Harmful to human health
– Residues in food can cause diseases.
Kills non-target species
– Affects bees, earthworms, and other beneficial organisms.
Bioaccumulation
– Pesticides accumulate in the food chain, harming top predators.
Alternatives
– Use organic manure, crop rotation, and integrated pest management.
18. What are the advantages of using renewable energy sources?
✅ Answer:
Renewable energy sources like solar, wind, hydro, and biomass are sustainable alternatives to fossil fuels.
Advantages:
Eco-friendly
– No pollution, reduces greenhouse gases.
Unlimited supply
– Unlike coal and petroleum, renewables won’t run out.
Cost-effective in the long run
– Once set up, solar and wind energy are free.
Reduces dependency on fossil fuels
– Helps in energy security.
Creates jobs
– Solar and wind industries generate employment.
Improves public health
– Reduces air pollution-related diseases.
19. How do human activities contribute to climate change?
✅ Answer:
Human activities have significantly increased global warming and climate change.
Major contributors:
Burning fossil fuels
– Increases CO₂ and other greenhouse gases.
Deforestation
– Reduces CO₂ absorption, increasing global temperatures.
Industrial emissions
– Release harmful pollutants into the air.
Agricultural practices
– Livestock farming produces methane gas.
Overuse of natural resources
– Leads to desertification and water scarcity.
Solutions
– Use renewable energy, afforestation, and sustainable practices.
20. How can we conserve natural resources?
✅ Answer:
Sustainable use of natural resources ensures their availability for future generations.
Ways to conserve natural resources:
Reduce, Reuse, Recycle
– Minimize waste and use eco-friendly products.
Use renewable energy
– Shift to solar, wind, and hydro energy.
Water conservation
– Rainwater harvesting and preventing water wastage.
Forest conservation
– Afforestation and strict laws against deforestation.
Energy conservation
– Use energy-efficient appliances and public transport.
Soil conservation
– Terracing, crop rotation, and organic farming.
