TRIPLE PLANETARY CRISIS (Chatpter -9) ~ Environamental Science
CHAPTER 9 – TRIPLE PLANETARY CRISIS
A. MULTIPLE CHOICE QUESTIONS
1. The Triple Planetary Crisis refers to:
(a) Poverty, unemployment and illiteracy
(b) Climate change, biodiversity loss and environmental pollution
(c) Deforestation, urbanisation and industrialisation
(d) Population growth, poverty and migration
Answer: (b) Climate change, biodiversity loss and environmental pollution
2. Which of the following is NOT a component of the Triple Planetary Crisis?
(a) Climate change
(b) Biodiversity loss
(c) Environmental pollution
(d) Economic instability
Answer: (d) Economic instability
3. Climate change is primarily caused by:
(a) Excessive rainfall
(b) Excessive emission of greenhouse gases
(c) Soil erosion
(d) Plastic recycling
Answer: (b) Excessive emission of greenhouse gases
4. Which of the following is a consequence of climate change?
(a) Stable weather patterns
(b) More frequent extreme weather events
(c) Increased biodiversity everywhere
(d) Reduced global temperature
Answer: (b) More frequent extreme weather events
5. Which gas is mainly associated with the greenhouse effect?
(a) Oxygen
(b) Carbon dioxide
(c) Nitrogen
(d) Hydrogen
Answer: (b) Carbon dioxide
6. Biodiversity refers to:
(a) Variety of minerals
(b) Variety of plants and animals in a particular habitat or ecosystem
(c) Amount of rainfall in an area
(d) Number of industries in a region
Answer: (b) Variety of plants and animals in a particular habitat or ecosystem
7. Which of the following is a major cause of biodiversity loss?
(a) Habitat destruction
(b) Afforestation
(c) Conservation
(d) Wildlife protection
Answer: (a) Habitat destruction
8. The permanent disappearance of a species from Earth is called:
(a) Migration
(b) Extinction
(c) Evolution
(d) Adaptation
Answer: (b) Extinction
9. The melting of glaciers is mainly associated with:
(a) Climate change
(b) Soil pollution
(c) Eutrophication
(d) Deforestation only
Answer: (a) Climate change
10. Which of the following is an example of environmental pollution?
(a) Afforestation
(b) Contamination of air, water and soil
(c) Wildlife conservation
(d) Rainwater harvesting
Answer: (b) Contamination of air, water and soil
11. Air pollution is caused mainly by:
(a) Harmful substances released into the atmosphere
(b) Planting trees
(c) Rainwater harvesting
(d) Composting
Answer: (a) Harmful substances released into the atmosphere
12. Which of the following is an air pollutant?
(a) Nitrogen oxides
(b) Oxygen
(c) Water vapour
(d) Hydrogen
Answer: (a) Nitrogen oxides
13. Particulate matter is commonly represented as:
(a) PM2.5 and PM10
(b) PM5 and PM20
(c) PM1 and PM100
(d) PM0 and PM50
Answer: (a) PM2.5 and PM10
14. Which pollutant is mainly released from coal-based power plants?
(a) Sulphur dioxide
(b) Oxygen
(c) Hydrogen
(d) Water vapour
Answer: (a) Sulphur dioxide
15. Carbon monoxide is represented by:
(a) CO₂
(b) CO
(c) C₂O
(d) CaO
Answer: (b) CO
16. Which of the following is a major source of carbon monoxide?
(a) Vehicle emissions
(b) Tree plantation
(c) Rainfall
(d) Composting
Answer: (a) Vehicle emissions
17. The Air Quality Index is abbreviated as:
(a) AQI
(b) AQL
(c) AQP
(d) AQC
Answer: (a) AQI
18. AQI is used to:
(a) Measure soil fertility
(b) Indicate air quality and associated health risks
(c) Measure rainfall
(d) Calculate biodiversity
Answer: (b) Indicate air quality and associated health risks
19. Water pollution means:
(a) Shortage of water
(b) Contamination of water bodies by harmful substances
(c) Excessive rainfall
(d) Conservation of water
Answer: (b) Contamination of water bodies by harmful substances
20. Which of the following can cause water pollution?
(a) Sewage
(b) Industrial discharge
(c) Agricultural runoff
(d) All of these
Answer: (d) All of these
21. Untreated domestic sewage mainly contains:
(a) Organic waste and pathogens
(b) Pure oxygen
(c) Minerals only
(d) Sand only
Answer: (a) Organic waste and pathogens
22. Industrial effluents may contain:
(a) Heavy metals
(b) Acids
(c) Toxic chemicals
(d) All of these
Answer: (d) All of these
23. Urban runoff may carry:
(a) Oil and grease
(b) Metals
(c) Waste
(d) All of these
Answer: (d) All of these
24. Mining activities can pollute water by releasing:
(a) Heavy metals and acidic water
(b) Oxygen
(c) Pure water
(d) Nitrogen only
Answer: (a) Heavy metals and acidic water
25. Thermal pollution is caused by:
(a) Discharge of hot water from industries and power plants
(b) Plastic waste
(c) Agricultural runoff
(d) Deforestation
Answer: (a) Discharge of hot water from industries and power plants
26. Thermal pollution affects aquatic organisms because it:
(a) Increases dissolved oxygen
(b) Reduces dissolved oxygen
(c) Increases biodiversity
(d) Purifies water
Answer: (b) Reduces dissolved oxygen
27. Eutrophication occurs when a water body becomes excessively enriched with:
(a) Nitrogen and phosphorus
(b) Oxygen and hydrogen
(c) Sand and clay
(d) Carbon monoxide
Answer: (a) Nitrogen and phosphorus
28. Excess nutrients in water cause rapid growth of:
(a) Fish
(b) Algae
(c) Trees
(d) Insects only
Answer: (b) Algae
29. The excessive growth of algae is known as:
(a) Algal bloom
(b) Acid rain
(c) Leaching
(d) Desertification
Answer: (a) Algal bloom
30. When algae die and decompose, they:
(a) Increase oxygen levels
(b) Consume dissolved oxygen
(c) Purify the water
(d) Increase water temperature only
Answer: (b) Consume dissolved oxygen
31. Soil pollution occurs when:
(a) Harmful substances accumulate in soil
(b) Soil is irrigated
(c) Crops are harvested
(d) Trees are planted
Answer: (a) Harmful substances accumulate in soil
32. Which of the following is a soil pollutant?
(a) Pesticides
(b) Heavy metals
(c) Chemical fertilisers
(d) All of these
Answer: (d) All of these
33. Excessive use of chemical fertilisers can cause:
(a) Soil acidification
(b) Increased biodiversity
(c) Pure groundwater
(d) Reduced pollution
Answer: (a) Soil acidification
34. Heavy metals such as lead, mercury and cadmium are:
(a) Beneficial nutrients
(b) Toxic pollutants
(c) Greenhouse gases
(d) Organic fertilisers
Answer: (b) Toxic pollutants
35. Industrial waste containing heavy metals can:
(a) Improve soil fertility
(b) Contaminate soil and groundwater
(c) Increase biodiversity
(d) Purify water
Answer: (b) Contaminate soil and groundwater
36. Leaching is the process by which:
(a) Harmful soluble substances are washed down through soil
(b) Soil is removed by wind
(c) Plants absorb sunlight
(d) Water evaporates from leaves
Answer: (a) Harmful soluble substances are washed down through soil
37. Leaching can contaminate:
(a) Groundwater
(b) Clouds
(c) Atmosphere only
(d) Sunlight
Answer: (a) Groundwater
38. Which of the following can be carried downward through soil during leaching?
(a) Fertilisers
(b) Pesticides
(c) Heavy metals
(d) All of these
Answer: (d) All of these
39. Plastic pollution is particularly harmful because plastic is:
(a) Easily biodegradable
(b) Non-biodegradable
(c) Quickly absorbed by plants
(d) A natural fertiliser
Answer: (b) Non-biodegradable
40. Plastic may remain in the environment for:
(a) A few hours
(b) A few days
(c) Hundreds of years
(d) Only one year
Answer: (c) Hundreds of years
41. Marine animals may mistake plastic for:
(a) Food
(b) Water
(c) Soil
(d) Oxygen
Answer: (a) Food
42. The 1986 nuclear disaster mentioned in the chapter occurred at:
(a) Bhopal
(b) Chernobyl
(c) Bengaluru
(d) Hangzhou
Answer: (b) Chernobyl
43. The Chernobyl disaster released:
(a) Radioactive materials
(b) Only carbon dioxide
(c) Plastic waste
(d) Sewage
Answer: (a) Radioactive materials
44. Radioactive materials from Chernobyl contaminated:
(a) Land and water bodies
(b) Only buildings
(c) Only roads
(d) Only the atmosphere for one day
Answer: (a) Land and water bodies
45. The Deepwater Horizon oil spill occurred in:
(a) 1986
(b) 2010
(c) 2015
(d) 2021
Answer: (b) 2010
46. The Deepwater Horizon disaster involved:
(a) An oil spill
(b) A nuclear explosion
(c) A forest fire
(d) Soil erosion
Answer: (a) An oil spill
47. The Great Smog of London occurred in:
(a) 1952
(b) 1962
(c) 1986
(d) 2010
Answer: (a) 1952
48. The Great Smog was mainly caused by:
(a) Burning of coal
(b) Plastic recycling
(c) Agricultural runoff
(d) Deforestation
Answer: (a) Burning of coal
49. The Bhopal Gas Tragedy occurred on:
(a) 2–3 December 1984
(b) 5 June 1986
(c) 15 August 1990
(d) 26 January 1984
Answer: (a) 2–3 December 1984
50. The Bhopal Gas Tragedy involved the release of:
(a) Toxic gas
(b) Radioactive material
(c) Oil
(d) Sewage
Answer: (a) Toxic gas
51. Which of the following is NOT a component of the Triple Planetary Crisis?
(a) Climate change
(b) Biodiversity loss
(c) Environmental pollution
(d) Population growth
Answer: (d) Population growth
52. Which of the following is an example of environmental pollution?
(a) Afforestation
(b) Recycling
(c) Industrial emissions
(d) Rainwater harvesting
Answer: (c) Industrial emissions
53. Which pollutant is mainly associated with vehicle emissions?
(a) Carbon monoxide
(b) Oxygen
(c) Nitrogen
(d) Hydrogen
Answer: (a) Carbon monoxide
54. PM2.5 refers to:
(a) Water particles
(b) Particulate matter of very small size
(c) Soil particles
(d) Plastic particles larger than 5 mm
Answer: (b) Particulate matter of very small size
55. The AQI is used to:
(a) Measure soil fertility
(b) Measure water availability
(c) Indicate air quality
(d) Measure biodiversity
Answer: (c) Indicate air quality
56. Which activity is a major source of air pollution?
(a) Burning fossil fuels
(b) Planting trees
(c) Recycling paper
(d) Rainwater harvesting
Answer: (a) Burning fossil fuels
57. Which of the following is a source of water pollution?
(a) Industrial discharge
(b) Afforestation
(c) Solar energy
(d) Rainwater harvesting
Answer: (a) Industrial discharge
58. Excess nutrients in water can result in:
(a) Deforestation
(b) Eutrophication
(c) Desertification only
(d) Habitat fragmentation
Answer: (b) Eutrophication
59. Algal blooms can cause:
(a) Increased dissolved oxygen
(b) Decreased dissolved oxygen
(c) Increased soil fertility
(d) Reduced pollution
Answer: (b) Decreased dissolved oxygen
60. Which of the following is a heavy metal pollutant?
(a) Mercury
(b) Oxygen
(c) Nitrogen
(d) Hydrogen
Answer: (a) Mercury
61. Excessive use of chemical fertilisers may lead to:
(a) Improved biodiversity
(b) Soil degradation
(c) Forest growth
(d) Reduced pollution
Answer: (b) Soil degradation
62. Which process can contaminate groundwater with soluble pollutants?
(a) Photosynthesis
(b) Leaching
(c) Respiration
(d) Evaporation
Answer: (b) Leaching
63. Which plastic particles are smaller than 5 mm?
(a) Macroplastics
(b) Microplastics
(c) Industrial plastics
(d) Plastic packaging
Answer: (b) Microplastics
64. Abandoned fishing nets are commonly known as:
(a) Green nets
(b) Ghost nets
(c) Food nets
(d) Soil nets
Answer: (b) Ghost nets
65. Plastic is particularly harmful because it is:
(a) Highly biodegradable
(b) Non-biodegradable
(c) A natural fertiliser
(d) Easily converted into soil
Answer: (b) Non-biodegradable
66. Biomagnification is associated with:
(a) Increasing concentration of toxic substances through food chains
(b) Increasing rainfall
(c) Decreasing temperature
(d) Increasing soil fertility
Answer: (a)
67. Biodiversity includes:
(a) Only animals
(b) Only plants
(c) Genetic, species and ecosystem diversity
(d) Only microorganisms
Answer: ©
68. Which of the following can cause biodiversity loss?
(a) Habitat destruction
(b) Conservation
(c) Afforestation
(d) Wildlife protection
Answer: (a) Habitat destruction
69. When the extinction of one species causes the extinction of another dependent species, it is called:
(a) Overfishing
(b) Co-extinction
(c) Leaching
(d) Eutrophication
Answer: (b) Co-extinction
70. Which of the following causes habitat fragmentation?
(a) Roads
(b) Wildlife protection
(c) Recycling
(d) Rainwater harvesting
Answer: (a) Roads
71. Which human activity directly contributes to climate change?
(a) Burning fossil fuels
(b) Tree plantation
(c) Recycling
(d) Rainwater harvesting
Answer: (a)
72. Which greenhouse gas is released from livestock farming?
(a) Methane
(b) Oxygen
(c) Hydrogen
(d) Nitrogen
Answer: (a) Methane
73. Which greenhouse gas is used as the reference gas for global warming potential?
(a) Methane
(b) Carbon dioxide
(c) Nitrous oxide
(d) CFC
Answer: (b) Carbon dioxide
74. Which activity reduces carbon footprint?
(a) Using private cars unnecessarily
(b) Using public transport
(c) Burning waste
(d) Deforestation
Answer: (b) Using public transport
75. Which of the following is NOT one of the 3Rs?
(a) Reduce
(b) Reuse
(c) Recycle
(d) Replace
Answer: (d) Replace
76. Trees help reduce climate change because they:
(a) Release large amounts of CO₂
(b) Absorb CO₂
(c) Increase pollution
(d) Destroy habitats
Answer: (b) Absorb CO₂
77. Climate change can result in:
(a) Melting glaciers
(b) Sea-level rise
(c) Extreme weather events
(d) All of the above
Answer: (d) All of the above
78. Which community is particularly vulnerable to climate change?
(a) Communities dependent on natural resources
(b) Communities with unlimited resources
(c) Only industrial communities
(d) None
Answer: (a)
B. FILL IN THE BLANKS
1. The three components of the Triple Planetary Crisis are climate change, biodiversity loss and __________.
Answer: environmental pollution
2. The permanent disappearance of a species is called __________.
Answer: extinction
3. The variety of plants and animals in a habitat is called __________.
Answer: biodiversity
4. Excessive emission of greenhouse gases contributes to __________.
Answer: climate change
5. AQI stands for __________.
Answer: Air Quality Index
6. PM2.5 and PM10 are forms of __________ matter.
Answer: particulate
7. Water pollution affects rivers, lakes, oceans and __________.
Answer: groundwater
8. Excess nutrients in water can cause __________.
Answer: eutrophication
9. Rapid growth of algae is called an __________.
Answer: algal bloom
10. Thermal pollution reduces the amount of dissolved __________ in water.
Answer: oxygen
11. Harmful substances accumulating in soil cause __________ pollution.
Answer: soil
12. Lead, mercury, cadmium and arsenic are examples of __________ metals.
Answer: heavy
13. The downward movement of soluble pollutants through soil is called __________.
Answer: leaching
14. Plastic is generally __________-biodegradable.
Answer: non
15. The Chernobyl nuclear disaster occurred in __________.
Answer: 1986
16. The Great Smog occurred in London in __________.
Answer: 1952
17. The Deepwater Horizon oil spill occurred in __________.
Answer: 2010
18. The Bhopal Gas Tragedy occurred in __________.
Answer: 1984
19. Agricultural runoff may contain fertilisers and __________.
Answer: pesticides
20. Hot water discharged by industries can cause __________ pollution.
Answer: thermal
21. The three components of the Triple Planetary Crisis are climate change, biodiversity loss and __________.
Answer: environmental pollution
22. The permanent disappearance of a species from Earth is called __________.
Answer: extinction
23. The variety of living organisms on Earth is known as __________.
Answer: biodiversity
24. The ongoing large-scale extinction of species caused mainly by human activities is called the __________.
Answer: Sixth Mass Extinction
25.Tiny plastic particles less than 5 mm in size are called __________.
Answer: microplastics
26. The accumulation of toxic substances at successive levels of a food chain is called __________.
Answer: biomagnification
27. The excessive enrichment of a water body with nutrients is called __________.
Answer: eutrophication
28. The rapid growth of algae caused by excess nutrients is called an __________.
Answer: algal bloom
29. The process by which soluble pollutants move down through soil is called __________.
Answer: leaching
30. The gas mainly associated with the burning of fossil fuels is __________.
Answer: carbon dioxide
31. The greenhouse gas released significantly by livestock farming is __________.
Answer: methane
32. The gas with a very high global warming potential mentioned in the chapter is __________.
Answer: chlorofluorocarbons (CFCs)
33. AQI stands for __________.
Answer: Air Quality Index
34. The natural process by which greenhouse gases trap heat is called the __________ effect.
Answer: greenhouse
35. The three principles used for reducing waste and carbon emissions are Reduce, Reuse and __________.
Answer: Recycle
36. Trees absorb __________ during photosynthesis.
Answer: carbon dioxide
37. Forests act as carbon __________.
Answer: sinks
38. The permanent loss of a species can disturb the ecological __________.
Answer: balance
C. VERY SHORT ANSWER QUESTIONS
1. What is the Triple Planetary Crisis?
Answer: The Triple Planetary Crisis refers to three interconnected global environmental challenges: climate change, biodiversity loss and environmental pollution.
2. What is climate change?
Answer: Climate change refers to long-term changes in temperature and weather patterns, largely caused by human activities and excessive greenhouse gas emissions.
3. What is biodiversity?
Answer: Biodiversity is the variety of plants and animals in a particular habitat or ecosystem.
4. What is biodiversity loss?
Answer: Biodiversity loss is the decline in the variety and number of plant and animal species and their habitats.
5. What is extinction?
Answer: Extinction is the permanent disappearance of a species from the Earth.
6. What is environmental pollution?
Answer: Environmental pollution is the introduction of harmful substances into the air, water or soil.
7. Name the three major types of environmental pollution discussed in the chapter.
Answer: Air pollution, water pollution and soil pollution.
8. What is air pollution?
Answer: Air pollution is the contamination of the atmosphere by harmful substances.
9. Name any four air pollutants.
Answer: Particulate matter, sulphur dioxide, nitrogen oxides and carbon monoxide.
10. What is AQI?
Answer: AQI stands for Air Quality Index. It indicates the quality of air and the possible health risks associated with it.
11. What is water pollution?
Answer: Water pollution is the contamination of water bodies by harmful substances.
12. What is thermal pollution?
Answer: Thermal pollution is the discharge of hot water from power plants and industries into water bodies, which raises water temperature and reduces dissolved oxygen.
13. What is eutrophication?
Answer: Eutrophication is the excessive enrichment of a water body with nutrients such as nitrates and phosphates.
14. What is an algal bloom?
Answer: An algal bloom is the rapid growth of algae caused by excess nutrients in a water body.
15. What is soil pollution?
Answer: Soil pollution occurs when harmful substances accumulate in soil, reducing its fertility and affecting plants, animals and humans.
16. Name four soil pollutants.
Answer: Pesticides, chemical fertilisers, lead and mercury.
17. What is leaching?
Answer: Leaching is the process in which rainwater carries soluble harmful substances downward through soil and may contaminate groundwater.
18. Why is plastic pollution dangerous?
Answer: Plastic is non-biodegradable and can remain in the environment for hundreds of years, harming terrestrial and marine organisms.
19. What happened during the Chernobyl disaster?
Answer: The 1986 Chernobyl nuclear disaster released large quantities of radioactive material into the atmosphere, contaminating surrounding land and water.
20. What was the Great Smog?
Answer: The Great Smog was a severe air-pollution event in London in 1952 caused mainly by extensive coal burning.
21. What is meant by Triple Planetary Crisis?
Answer: The Triple Planetary Crisis refers to three interconnected global environmental challenges: climate change, biodiversity loss, and environmental pollution.
22. Name the three components of the Triple Planetary Crisis.
Answer:
Climate change
Biodiversity loss
Environmental pollution
3. What is environmental pollution?
Answer: Environmental pollution is the introduction of harmful substances into the environment, affecting air, water, soil, ecosystems and human health.
24. Name any three types of pollution.
Answer: Air pollution, water pollution and soil pollution.
25. What is biodiversity?
Answer: Biodiversity is the variety of living organisms, including plants, animals, microorganisms and the ecosystems they form.
26. What is biodiversity loss?
Answer: Biodiversity loss is the decline in the number, variety and variability of living organisms.
27. What is extinction?
Answer: Extinction is the permanent disappearance of a species from the Earth.
28. What is the Sixth Mass Extinction?
Answer: It refers to the ongoing large-scale extinction of plant and animal species, mainly caused by human activities.
29. What is climate change?
Answer: Climate change refers to long-term alterations in Earth's temperature and weather patterns.
30. What are greenhouse gases?
Answer: Greenhouse gases are atmospheric gases that absorb and trap heat, contributing to the greenhouse effect and global warming.
31. Give two examples of greenhouse gases.
Answer: Carbon dioxide (CO₂) and methane (CH₄).
32. What is the greenhouse effect?
Answer: The greenhouse effect is the natural process by which certain gases in the atmosphere trap heat and keep Earth warm.
33. What is carbon footprint?
Answer: A carbon footprint is the total amount of greenhouse gases, mainly carbon dioxide, released directly or indirectly by an individual, organisation, product or country.
34. What is meant by CO₂ equivalent?
Answer: CO₂ equivalent (CO₂e) is a measure used to express the warming effect of different greenhouse gases in terms of the equivalent amount of CO₂.
35. What is biomagnification?
Answer: Biomagnification is the process by which the concentration of toxic substances increases at each successive level of a food chain.
36. What is eutrophication?
Answer: Eutrophication is the process in which a water body becomes excessively enriched with nutrients such as nitrates and phosphates.
37. What is an algal bloom?
Answer: An algal bloom is the rapid growth of algae in a water body due to excess nutrients.
38. What is leaching?
Answer: Leaching is the process by which harmful chemicals and soluble substances are washed down through soil and contaminate groundwater.
39. What are microplastics?
Answer: Microplastics are tiny plastic particles less than 5 mm in size.
40. What are macroplastics?
Answer: Macroplastics are large plastic wastes such as fishing nets, plastic containers and discarded plastic sheets.
41. What is plastic pollution?
Answer: Plastic pollution is the accumulation of plastic waste in the environment due to its large-scale production and improper disposal.
42. What is habitat fragmentation?
Answer: Habitat fragmentation occurs when natural habitats are divided into smaller areas by roads, agriculture, urban development or other human activities.
43. What is co-extinction?
Answer: Co-extinction occurs when the extinction of one species causes the extinction of another species that depends on it.
44. What is overexploitation?
Answer: Overexploitation is the excessive use of natural resources beyond sustainable levels.
45. What is overfishing?
Answer: Overfishing is excessive fishing that reduces fish populations faster than they can reproduce.
D. SHORT ANSWER QUESTIONS
1. Explain the three components of the Triple Planetary Crisis.
Answer:
The three components are:
Climate change – Long-term changes in temperature and weather patterns caused largely by greenhouse gas emissions.
Biodiversity loss – Decline in species, habitats and ecosystems due to human activities.
Environmental pollution – Contamination of air, water and soil by harmful substances.
These three problems are interconnected and collectively threaten ecological stability and human well-being.
2. How are climate change and biodiversity loss connected?
Answer:
Climate change alters temperature, rainfall and weather patterns. These changes destroy or modify habitats and make it difficult for many species to survive. Rising temperatures, melting glaciers and extreme weather events can therefore cause species decline and extinction.
3. Mention the major causes of biodiversity loss.
Answer:
Major causes include:
Habitat destruction
Deforestation
Pollution
Climate change
Overexploitation of natural resources
Human activities such as urbanisation and industrialisation
4. How does habitat destruction lead to extinction?
Answer:
When forests, wetlands and other natural habitats are destroyed, animals and plants lose their food, shelter and breeding grounds. If they cannot adapt or move to suitable habitats, their populations decline and may eventually become extinct.
5. Explain the major sources of air pollution.
Answer:
Major sources include:
Vehicle emissions
Burning of fossil fuels
Coal-based power plants
Industrial emissions
Construction activities
Waste burning
Volcanic eruptions and wildfires
6. Name the major air pollutants and their sources.
Answer:
Pollutant
Major source
Particulate Matter
Vehicle emissions, construction
Sulphur Dioxide
Coal-based power plants
Nitrogen Oxides
Vehicle emissions, power plants
Carbon Monoxide
Incomplete combustion, vehicle emissions
Ozone
Formed through atmospheric reactions
7. What are the effects of air pollution on human health?
Answer:
Air pollution can cause respiratory diseases, cardiovascular problems and other health disorders. Long-term exposure can increase the risk of serious illness and premature death.
8. Explain the importance of AQI.
Answer:
The Air Quality Index provides information about the level of air pollution in an area. It helps people understand possible health risks and take precautions when air quality is poor.
9. Explain the major sources of water pollution.
Answer:
Water pollution may result from:
Domestic sewage
Industrial effluents
Agricultural runoff
Mining activities
Urban runoff
Thermal pollution
Improper waste disposal
10. How does agricultural runoff cause water pollution?
Answer:
Rainwater can wash fertilisers, pesticides and other chemicals from agricultural fields into rivers, lakes and groundwater. These substances contaminate water and may cause eutrophication.
11. How do industrial effluents pollute water?
Answer:
Industries may discharge untreated wastewater containing heavy metals, acids, chemicals and other toxic substances. These pollutants contaminate water bodies and can harm aquatic organisms and human health.
12. Explain thermal pollution and its effects.
Answer:
Thermal pollution occurs when hot water from industries and power plants is discharged into water bodies. It raises the temperature of the water and reduces dissolved oxygen. This can affect the survival of aquatic organisms.
13. Why are the three components of the Triple Planetary Crisis interconnected?
Answer:
Climate change, biodiversity loss and pollution are interconnected because each can worsen the others. Pollution damages ecosystems and species, while climate change alters habitats and increases species loss. Biodiversity loss can also reduce ecosystem resilience and their ability to regulate climate and absorb pollutants.
14. Mention three major causes of environmental pollution.
Answer:
Burning of fossil fuels
Industrial activities and waste
Improper disposal of domestic and plastic waste
15. How does air pollution affect human health?
Answer:
Air pollution can cause respiratory diseases, cardiovascular problems and lung infections. Long-term exposure can lead to serious health problems and premature death.
16. How does air pollution affect plants?
Answer:
Air pollutants can damage plant tissues and interfere with photosynthesis. Pollutants may also react with sunlight to form smog, reducing sunlight and affecting plant growth.
17. What are the major sources of air pollution mentioned in the chapter?
Answer:
Burning of fossil fuels
Vehicle emissions
Industrial emissions
Construction activities
Burning of waste
Wildfires and volcanic activity
18. How does water pollution affect aquatic organisms?
Answer:
Water pollution can reduce water quality and dissolved oxygen. Toxic chemicals and oil spills can harm or kill fish and other aquatic organisms.
19. What is eutrophication? How does it affect aquatic life?
Answer:
Eutrophication occurs when excessive nutrients such as nitrates and phosphates enter water bodies. It causes algal blooms, which reduce dissolved oxygen when the algae decompose, resulting in the death of fish and other aquatic organisms.
20. How do chemical fertilisers cause soil pollution?
Answer:
Excessive use of chemical fertilisers alters the natural composition of soil and may cause soil acidification. Excess nutrients can also leach into groundwater and cause water pollution.
21. What are the effects of heavy metals on soil?
Answer:
Heavy metals such as lead, mercury, cadmium and arsenic are toxic and may remain in soil for long periods. They reduce soil quality and can enter plants and the food chain, causing health problems.
22. What is leaching? Why is it dangerous?
Answer:
Leaching is the movement of soluble harmful substances through soil into groundwater. It is dangerous because pollutants such as pesticides, fertilisers, heavy metals and industrial chemicals can contaminate underground water sources.
23. Why is plastic pollution a serious environmental problem?
Answer:
Plastic is largely non-biodegradable and can remain in the environment for hundreds of years. It accumulates in land, rivers and oceans and can injure, poison or kill animals.
24. Differentiate between microplastics and macroplastics.
Answer:
Microplastics
Macroplastics
Less than 5 mm in size
Large plastic items
May form from breakdown of larger plastics
Include fishing nets, containers and plastic sheets
Can enter the food chain
Can cause physical injury or entanglement
25. What are ghost nets?
Answer:
Ghost nets are abandoned fishing nets that continue to trap marine animals such as fish, turtles and seabirds, causing injury or death.
26. What is biomagnification and why is it dangerous?
Answer:
Biomagnification is the increase in concentration of toxic substances at successive trophic levels. It is dangerous because organisms at higher levels of the food chain can accumulate very high concentrations of toxins.
27. Mention three major causes of biodiversity loss.
Answer:
Habitat destruction
Overexploitation of natural resources
Pollution and climate change
28. How does habitat fragmentation cause biodiversity loss?
Answer:
Habitat fragmentation divides habitats into smaller isolated areas. This restricts the movement of animals, reduces genetic diversity and makes populations more vulnerable to extinction.
29. What is overexploitation? Give two examples.
Answer:
Overexploitation is the excessive use of natural resources beyond sustainable levels. Examples include overfishing and excessive logging.
30. What are invasive species?
Answer:
Invasive species are non-native species introduced into a new environment where they spread rapidly and compete with native species for food and space.
31. What is co-extinction? Explain with an example.
Answer:
Co-extinction occurs when the extinction of one species leads to the extinction of another species dependent on it. For example, if a host plant disappears, insects that depend solely on that plant may also become extinct.
32. How does biodiversity support human life?
Answer:
Biodiversity provides food, medicine, clean air and water and helps regulate climate. It also maintains ecological balance and supports ecosystem services essential for human survival.
E. EUTROPHICATION – IMPORTANT QUESTIONS
1. What is eutrophication? Explain its process.
Answer:
Eutrophication occurs when a water body becomes excessively enriched with nutrients such as nitrates and phosphates.
The process is:
Excess nutrients → Rapid algal growth → Algal bloom → Algae die → Decomposition → Oxygen consumption → Reduced dissolved oxygen → Death of aquatic organisms
2. Why does eutrophication harm aquatic organisms?
Answer:
Excess nutrients cause algal blooms. When algae die, decomposers break them down and consume dissolved oxygen. The resulting oxygen shortage makes it difficult for fish and other aquatic organisms to survive and may cause their death.
3. What are the major causes of eutrophication?
Answer:
Agricultural runoff
Excess fertilisers
Sewage discharge
Industrial waste containing nutrients
F. SOIL POLLUTION
1. What are the major soil pollutants?
Answer:
The major soil pollutants include:
Pesticides and insecticides
Chemical fertilisers
Heavy metals
Industrial waste
Biomedical and hazardous waste
Plastic waste
2. How do pesticides affect soil?
Answer:
Excessive use of pesticides contaminates soil, reduces soil fertility and may kill beneficial microorganisms. These chemicals may also enter the food chain and affect human and animal health.
3. How do chemical fertilisers cause soil pollution?
Answer:
Excessive use of nitrogen-, phosphorus- and potassium-based fertilisers can alter the natural composition of soil, reduce productivity over time and cause soil acidification. Some nutrients may also leach into groundwater.
4. Why are heavy metals dangerous soil pollutants?
Answer:
Heavy metals such as lead, mercury, cadmium and arsenic are toxic. They can remain in soil for long periods, reduce soil quality, accumulate in plants and enter the food chain, causing health problems.
5. How does industrial waste contaminate soil?
Answer:
Factories may dump untreated solid and chemical waste containing acids, solvents and toxic substances on land. These pollutants contaminate soil and may enter nearby water sources through leaching.
G. LEACHING
1. Explain the process of leaching.
Answer:
Leaching occurs when rainwater passes through soil, landfills or agricultural fields and dissolves soluble pollutants such as fertilisers, pesticides, heavy metals and industrial chemicals. These dissolved substances move downward and may contaminate groundwater.
2. Why is leaching dangerous?
Answer:
Leaching can transfer harmful chemicals from contaminated soil into groundwater. Since groundwater is an important source of drinking and irrigation water, contamination can threaten human health, agriculture and ecosystems.
H. PLASTIC POLLUTION
1. Why has plastic pollution become a major environmental crisis?
Answer:
Plastic is produced in enormous quantities and a large amount is improperly disposed of. Since plastic is non-biodegradable, it remains in the environment for hundreds of years. It accumulates in soil, water bodies and marine ecosystems.
2. How does plastic affect marine animals?
Answer:
Marine animals may mistake plastic for food or become entangled in plastic debris. This can cause injury, starvation and even death.
3. Explain the relationship between plastic pollution and soil pollution.
Answer:
Plastic waste accumulates in soil because it does not readily decompose. It can interfere with soil quality and may contribute to the movement of harmful substances through the environment.
I. IMPORTANT CASE STUDIES
1. Explain the Deepwater Horizon oil spill.
Answer:
The Deepwater Horizon oil spill occurred in 2010. An explosion at an offshore oil rig resulted in a massive oil spill into the Gulf of Mexico. The disaster caused severe damage to marine ecosystems and affected fishing and wildlife.
2. What was the Great Smog of London?
Answer:
The Great Smog occurred in London in 1952. Extensive coal burning released pollutants into the atmosphere. Weather conditions trapped the pollutants close to the ground, creating severe smog. It caused major health problems and many deaths.
3. Describe the Bhopal Gas Tragedy.
Answer:
The Bhopal Gas Tragedy occurred on the night of 2–3 December 1984. A toxic gas leak from an industrial plant exposed nearby people to poisonous substances. It resulted in deaths, serious health problems and long-term environmental consequences.
4. Explain the Chernobyl nuclear disaster.
Answer:
The Chernobyl nuclear disaster occurred in 1986 in Ukraine. A nuclear accident released large quantities of radioactive material into the atmosphere. Radioactive substances contaminated surrounding land, forests and water bodies and caused long-term environmental and health effects.
J. APPLICATION-BASED QUESTIONS
1. A lake near a farming region suddenly develops a thick layer of green algae. Fish begin dying soon afterwards. What is the most likely cause?
Answer:
The lake is probably experiencing eutrophication. Fertilisers from agricultural runoff may have introduced excess nitrates and phosphates, causing an algal bloom. Decomposition of dead algae reduced dissolved oxygen, resulting in fish deaths.
2. A farmer uses large quantities of pesticides every year. After several years, crop productivity decreases. Give two possible reasons.
Answer:
Excessive pesticide use can reduce beneficial soil microorganisms.
It can contaminate and reduce soil fertility.
3. A factory releases untreated wastewater containing heavy metals into a nearby river. What are two likely consequences?
Answer:
Water contamination and harm to aquatic organisms.
Heavy metals may accumulate in organisms and enter the food chain, posing health risks to humans.
4. Rain falls heavily over a field that has recently received excessive fertiliser. The nearby well becomes contaminated. Explain how.
Answer:
Rainwater dissolves soluble fertilisers and carries them downward through the soil by leaching. The pollutants eventually reach and contaminate groundwater, including the water in the well.
5. A city experiences heavy traffic and poor air quality. Which pollutants would you expect to increase?
Answer:
Particulate matter, carbon monoxide and nitrogen oxides are likely to increase because they are commonly associated with vehicle emissions.
6. A power plant releases hot water into a nearby river. Fish populations decline. Why?
Answer:
The hot water causes thermal pollution, increasing the temperature of the river and reducing dissolved oxygen. This creates unsuitable conditions for aquatic organisms.
7. A coastal region has large quantities of plastic waste. Sea turtles and other marine animals are found injured. Explain the connection.
Answer:
Marine animals may mistake plastic for food or become entangled in plastic debris. This can cause injury, starvation and death.
K. HIGH-ORDER THINKING QUESTIONS
1. Why is the Triple Planetary Crisis called “triple” but its components cannot be treated separately?
Answer:
Climate change, biodiversity loss and pollution are interconnected. For example, pollution can contribute to climate change, while climate change can destroy habitats and cause biodiversity loss. Biodiversity loss can also weaken ecosystem services that help regulate climate and maintain environmental quality. Therefore, solving one problem requires consideration of the others.
2. “Human activities are the major drivers of the Triple Planetary Crisis.” Justify.
Answer:
Human activities such as fossil-fuel burning, industrialisation, deforestation, intensive agriculture, mining, urbanisation and improper waste disposal release pollutants, increase greenhouse gases, destroy habitats and deplete natural resources. These activities therefore contribute significantly to all three components of the crisis.
3. Why can pollution in one part of the environment affect other parts?
Answer:
The atmosphere, water, soil and living organisms are interconnected. For example, pesticides applied to soil can be washed into rivers, while industrial air pollutants can settle on soil and water. Thus, pollution can move between environmental components.
4. Why is biodiversity important for human survival?
Answer:
Biodiversity provides food, medicine, ecological services and natural resources. Healthy ecosystems also support pollination, soil fertility, water purification and climate regulation. Therefore, biodiversity loss can threaten human well-being and survival.
5. Why is prevention of pollution better than cleaning polluted environments later?
Answer:
Preventing pollution reduces environmental damage at its source. Once pollutants enter soil, water or ecosystems, they may be difficult and expensive to remove and can cause long-term health and ecological effects.
L. ASSERTION–REASONING
Choose:
(a) Both A and R are true, and R is the correct explanation of A.
(b) Both A and R are true, but R is not the correct explanation of A.
(c) A is true, but R is false.
(d) A is false, but R is true.
1.
Assertion (A): Excessive fertiliser use can cause water pollution.
Reason (R): Fertilisers can be washed into water bodies through agricultural runoff.
Answer: (a)
2.
Assertion (A): Eutrophication can cause fish deaths.
Reason (R): Decomposition of algae consumes dissolved oxygen.
Answer: (a)
3.
Assertion (A): Plastic pollution is difficult to control naturally.
Reason (R): Plastic is generally non-biodegradable.
Answer: (a)
4.
Assertion (A): Thermal pollution can harm aquatic organisms.
Reason (R): Hot water can reduce dissolved oxygen in water.
Answer: (a)
5.
Assertion (A): Leaching can contaminate groundwater.
Reason (R): Rainwater can carry soluble pollutants downward through soil.
Answer: (a)
6.
Assertion (A): Biodiversity loss may lead to ecosystem imbalance.
Reason (R): Different organisms perform important roles in ecosystems.
Answer: (a)
7.
Assertion (A): Heavy metals are safe soil pollutants because they decompose rapidly.
Reason (R): Lead and mercury can remain in soil for long periods.
Answer: (d)
8.
Assertion (A): AQI helps people understand air pollution levels.
Reason (R): AQI provides an indication of air quality and associated health risks.
Answer: (a)
N. CASE STUDY QUESTIONS
Case Study 1 – Agricultural Runoff
A farming region uses large quantities of nitrogen- and phosphorus-based fertilisers. During heavy rainfall, these substances are washed into a nearby lake. Soon, the lake develops a thick green algal layer. After some time, many fish are found dead.
Questions:
1. What environmental process is taking place?
Answer: Eutrophication.
2. What causes the rapid growth of algae?
Answer: Excess nutrients, particularly nitrates and phosphates.
3. Why do fish die?
Answer: Decomposition of dead algae consumes dissolved oxygen, creating oxygen-deficient conditions.
4. What is the major source of these nutrients?
Answer: Agricultural runoff carrying excessive fertilisers.
Case Study 2 – Contaminated Groundwater
A factory dumps untreated chemical waste on nearby land. During the monsoon, rainwater passes through the contaminated soil and carries dissolved chemicals into the groundwater.
Questions:
1. Name the process involved.
Answer: Leaching.
2. What environmental resource becomes contaminated?
Answer: Groundwater.
3. Name two pollutants that may be carried through leaching.
Answer: Heavy metals and industrial chemicals.
4. Why is this dangerous to humans?
Answer: Contaminated groundwater may be used for drinking and can expose people to toxic substances.
Case Study 3 – Urban Air Pollution
A large city experiences increasing vehicle traffic and industrial activity. The city frequently records poor AQI levels. Residents complain of breathing difficulties.
Questions:
1. What type of pollution is involved?
Answer: Air pollution.
2. Name two pollutants likely to be present.
Answer: Particulate matter and nitrogen oxides.
3. What does AQI stand for?
Answer: Air Quality Index.
4. What does AQI indicate?
Answer: It indicates air quality and associated health risks.
Case Study 4 – Plastic Pollution
A coastal area receives large quantities of plastic waste. Plastic bags, bottles and packaging materials accumulate along the shore. Marine animals are frequently found injured or dead.
Questions:
1. Why does plastic remain in the environment for long periods?
Answer: Plastic is generally non-biodegradable.
2. How can marine animals be harmed by plastic?
Answer: They may mistake it for food or become entangled in plastic debris.
3. Name two consequences for marine animals.
Answer: Injury and starvation; plastic can also cause death.
O. LONG ANSWER QUESTIONS
1. Explain the Triple Planetary Crisis in detail.
Answer:
The Triple Planetary Crisis consists of climate change, biodiversity loss and environmental pollution.
Climate change refers to long-term changes in temperature and weather patterns. Excessive greenhouse gas emissions from human activities are a major cause.
Biodiversity loss refers to the decline in species, habitats and ecosystems. Habitat destruction, deforestation, pollution, overexploitation and climate change contribute to it.
Environmental pollution occurs when harmful substances contaminate air, water and soil. Air pollution comes from vehicles, industries and fossil-fuel burning. Water pollution results from sewage, industrial effluents, agricultural runoff and other sources. Soil pollution is caused by pesticides, fertilisers, heavy metals and waste.
These three crises are interconnected and threaten ecosystems, human health, food security and future generations.
2. Explain the causes and effects of biodiversity loss.
Answer:
Causes:
Habitat destruction
Deforestation
Urbanisation
Industrialisation
Pollution
Climate change
Overexploitation of natural resources
Effects:
Decline and extinction of species
Destruction of food chains
Ecosystem imbalance
Loss of important ecosystem services
Reduced availability of natural resources
Threats to human food, medicine and livelihoods
3. Explain air pollution, its sources and effects.
Answer:
Air pollution is the contamination of the atmosphere by harmful substances.
Sources:
Vehicle emissions
Coal-based power plants
Industrial activities
Construction work
Waste burning
Wildfires and volcanic activity
Major pollutants:
Particulate matter
Sulphur dioxide
Nitrogen oxides
Carbon monoxide
Effects:
Air pollution can cause respiratory and cardiovascular diseases, damage ecosystems and reduce overall environmental quality. AQI is used to indicate air quality and associated health risks.
4. Explain water pollution and its major sources.
Answer:
Water pollution is the contamination of water bodies such as rivers, lakes, oceans and groundwater by harmful substances.
Major sources include:
Domestic sewage – Contains organic waste, detergents and pathogens.
Industrial effluents – May contain heavy metals, acids and toxic chemicals.
Agricultural runoff – Carries fertilisers and pesticides.
Urban runoff – Carries oil, grease, metals and waste.
Mining activities – Release heavy metals and acidic water.
Thermal pollution – Hot water from industries and power plants raises water temperature.
Water pollution harms aquatic organisms, ecosystems and human health.
5. Explain soil pollution and its major pollutants.
Answer:
Soil pollution occurs when harmful substances accumulate in soil, reducing its fertility and affecting plants, animals and humans.
Major pollutants include:
Pesticides and insecticides: Can kill beneficial soil microorganisms and contaminate food chains.
Chemical fertilisers: Excessive use can cause soil acidification and reduce productivity.
Heavy metals: Lead, mercury, cadmium and arsenic are toxic and can remain in soil for long periods.
Industrial waste: Contains toxic chemicals that may contaminate soil and groundwater.
Biomedical and hazardous waste: May contain pathogens and toxic substances.
Plastic waste: Remains in the environment for long periods.
3. Differentiate between eutrophication and leaching.
Eutrophication
Leaching
Occurs mainly in water bodies
Occurs through soil
Caused by excess nutrients
Caused by downward movement of soluble substances
Leads to algal blooms
Can contaminate groundwater
Reduces dissolved oxygen
Transfers pollutants to underground water
4. Explain how human activities contribute to all three components of the Triple Planetary Crisis.
Answer:
Burning fossil fuels releases greenhouse gases, causing climate change. Deforestation, habitat destruction, overexploitation and pollution cause biodiversity loss. Industrial emissions, sewage, agricultural chemicals, plastics and improper waste disposal cause environmental pollution. Thus, human activities contribute directly and indirectly to all three components.
Q. EXTRA THINKING QUESTIONS
1. Why can a decrease in biodiversity affect humans?
Answer:
Loss of biodiversity can reduce food sources, medicinal resources, pollination, soil fertility, water purification and other ecosystem services on which humans depend.
2. Why is groundwater contamination particularly serious?
Answer:
Groundwater is an important source of drinking and irrigation water. Once contaminated, pollutants can remain underground for long periods and are difficult to remove.
3. Why should excessive use of chemical fertilisers be avoided?
Answer:
Excessive fertilisers can reduce soil fertility, cause soil acidification, pollute groundwater and contribute to eutrophication when washed into water bodies.
4. Why are heavy metals considered persistent pollutants?
Answer:
Heavy metals such as lead, mercury and cadmium do not readily break down and can remain in soil for long periods, entering food chains and causing toxicity.
5. How are soil pollution and water pollution interconnected?
Answer:
Pollutants present in soil can be washed into rivers and lakes by runoff or carried into groundwater through leaching. Therefore, soil pollution can eventually cause water pollution.
6. Why is plastic pollution both a land and water pollution problem?
Answer:
Plastic accumulates on land because it is non-biodegradable and can enter rivers, lakes and oceans through improper disposal and runoff. Thus, it affects both terrestrial and aquatic ecosystems.
7. Explain the Triple Planetary Crisis in detail.
Answer:
The Triple Planetary Crisis consists of three interconnected environmental challenges:
Climate change – Long-term changes in Earth's temperature and weather patterns, mainly caused by increasing greenhouse gas emissions.
Biodiversity loss – Decline in the number and variety of living organisms due to habitat destruction, pollution, overexploitation and climate change.
Environmental pollution – Contamination of air, water and soil by harmful substances.
These problems are interconnected. For example, deforestation causes biodiversity loss and releases carbon dioxide, contributing to climate change. Pollution damages ecosystems and can cause species extinction. Therefore, solving one problem often helps address the others.
8. Explain the major causes and effects of air pollution.
Answer:
Air pollution is caused by harmful substances released into the atmosphere.
Major causes:
Burning of fossil fuels
Vehicle emissions
Industrial activities
Construction
Burning of waste
Wildfires
Effects on the environment:
Formation of smog
Reduced visibility
Reduced sunlight reaching plants
Damage to ecosystems
Effects on humans:
Respiratory problems
Asthma
Lung infections
Cardiovascular problems
Premature deaths
9. Explain water pollution and its major sources.
Answer:
Water pollution refers to contamination of water bodies such as rivers, lakes, oceans and groundwater by harmful substances.
Major sources include:
Domestic sewage
Industrial effluents
Agricultural runoff
Mining activities
Oil spills
Thermal pollution
Polluted water can spread diseases, harm aquatic organisms and reduce the availability of safe drinking water.
10. Explain eutrophication and its consequences.
Answer:
Eutrophication occurs when excessive amounts of nutrients such as nitrates and phosphates enter a water body.
The process is: Excess nutrients → rapid algal growth → algal bloom → algae die → decomposition increases → dissolved oxygen decreases → aquatic organisms die.
Thus, eutrophication disturbs aquatic ecosystems and reduces water quality.
11. Explain soil pollution and its major pollutants.
Answer:
Soil pollution occurs when harmful substances accumulate in soil, reducing its fertility and affecting plants, animals and humans.
Major soil pollutants include:
Pesticides and insecticides – Kill beneficial soil microorganisms and may enter the food chain.
Chemical fertilisers – Can cause soil acidification and reduce soil productivity.
Heavy metals – Lead, mercury, cadmium and arsenic can remain in soil for long periods.
Industrial waste – May contain toxic chemicals that contaminate soil.
Biomedical and hazardous waste – Can introduce pathogens and toxic chemicals into soil.
12. Explain the process of leaching.
Answer:
Leaching occurs when rainwater passes through soil, landfills or agricultural fields and dissolves soluble pollutants.
Process:
Rainwater
↓
passes through contaminated soil
↓
dissolves soluble pollutants
↓
pollutants move downward
↓
groundwater becomes contaminated
Pollutants involved may include fertilisers, pesticides, heavy metals and industrial chemicals.
13. Explain the different types of plastic pollutants.
Answer:
a. Single-use plastics:
Plastic bags, straws, bottles, packaging materials and disposable cutlery used once and discarded.
b. Microplastics:
Plastic particles smaller than 5 mm, formed through breakdown of larger plastics or released from synthetic materials.
c. Macroplastics:
Large plastic objects such as fishing nets and containers.
d. Plastic packaging:
Packaging used for food, e-commerce and consumer goods. Improper disposal causes urban flooding and land pollution.
e. Industrial plastic waste:
Plastic waste produced by manufacturing industries, including pellets and synthetic materials.
14. Explain the causes of biodiversity loss.
Answer:
Major causes include:
Habitat destruction due to deforestation, urbanisation and infrastructure.
Overexploitation such as overfishing, hunting and excessive logging.
Pollution, which damages habitats and harms organisms.
Climate change, which changes temperature and weather patterns.
Habitat fragmentation, which isolates populations.
Invasive species, which compete with native species.
Human-animal conflict, caused by shrinking natural habitats.
15. Explain the Sixth Mass Extinction.
Answer:
Earth has experienced five major mass extinctions due to natural causes such as volcanic activity, climate changes and asteroid impacts. The Sixth Mass Extinction is different because it is mainly driven by human activities.
Major causes include:
Habitat destruction
Deforestation
Pollution
Climate change
Overexploitation
Invasive species
The present rate of extinction is much higher than the natural background rate, making biodiversity conservation an urgent global priority.
16. Explain how human activities contribute to climate change.
Answer:
Human activities increase greenhouse gas emissions.
Major activities include:
Burning coal, petroleum and natural gas
Industrial production
Manufacturing
Construction
Transportation
Fossil-fuel-based electricity generation
Deforestation
Agriculture and livestock farming
Excessive consumption and waste generation
These activities increase greenhouse gases such as CO₂, methane and nitrous oxide, strengthening the greenhouse effect and causing global warming.
17. Explain the effects of increased greenhouse gases.
Answer:
Increased greenhouse gases cause:
Global warming – Earth's average temperature rises.
Melting of glaciers and polar ice caps – Himalayan glaciers are shrinking.
Sea-level rise – Coastal and low-lying areas become vulnerable to flooding.
Extreme weather events – Floods, cyclones, droughts and heatwaves become more frequent or intense.
Ecosystem disruption – Species and habitats are affected.
Health impacts – Heat-related illness and some vector-borne diseases may increase.
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