Chapter 14 – Environmental Pollution

The chapter Environmental Pollution is an important part of the WBBSE Class 10 Geography syllabus. It is very useful for your Madhyamik exam and questions often come from this chapter. This page has simple questions and answers from this topic. All answers are written in easy English so you can understand them quickly.
You can use this page for quick revision, clear your basic ideas, and get better marks in your exam.

Content Structure

1. Multiple choice questions and answers (MCQs)
2. Very short-type questions and answers
- 2A. Fill in the blanks
- 2B. True or false
- 2C. Match the following
- 2D. Single word questions and answers
3. Short-type questions and answers
4. Long-type questions and answers

1. Multiple choice questions and answers (MCQs)

1. The different strata of air, soil and water where living organs survive or live together is called-
(a) Biosphere
(b) Atmosphere
(c) Stratosphere
(d) Lithosphere

Ans: (a) Biosphere

2. Which one is the major pollution agent?
(a) Animals
(b) Plants
(c) Man
(d) None of these

Ans: (c) Man

3. One of the main air pollutant is-
(a) CO
(b) CO2
(c) Sulphur
(d) O2

Ans: (a) CO

4. Maximum air pollution caused by –
(a) Household wates and insecticides
(b) Automobile exhausts and chemicals liberated industry
(c) Sewage and pesticides
(d) Swage and industrial effluents

Ans: (b) Automobile exhausts and chemicals liberated industry

5. Which of the following is the main factor in water pollution?
(a) Pesticides
(b) Detergent
(c) Industrial wastes
(d) Automobile exhausts

Ans: (c) Industrial wastes

6. Which one of the disease caused due to air pollution?
(a) Lung cancer
(b) Headache
(c) Cholera
(d) Dysentery

Ans: (a) Lung cancer

7. The term ‘Biomagnification’ refers to the-
(a) Growth of organism due to food consumption
(b) Increase in the size of population
(c) Blowing up of environmental issues by man
(d) Increase in concentration of non-degradable pollutants as they pass through food chain

Ans: (d) Increase in concentration of non-degradable pollutants as they pass through food chain

8. Green house effect due to-
(a) CO2
(b) CO
(c) NO
(d) PO4

Ans: (a) CO2

9. Which of the following metals causes harmful effects?
(a) Lead
(b) Uranium
(c) Cobalt
(d) All of these

Ans: (d) All of these

10. Which one of the following is not a green house gas?
(a) CFC
(b) Ozone
(c) SO2
(d) N2O

Ans: (c) SO₂

11. Which one of the following is not an air pollutant?
(a) Carbon monoxide
(b) Pollen from plants
(c) Phosphates
(d) Hydrocarbons

Ans: (c) Phosphates

12. Which of the following is not a green house gas?
(a) Methane
(b) Water vapour
(c) Oxygen
(d) Carbon monoxide

Ans: (c) Oxygen

13. Algal blooms impart a distinct colour to water due to-
(a) Their pigments
(b) Excretion of coloured substances
(c) Formation of coloured chemicals in water facilitated by physiological degradation of algae
(d) Absorption of light by algal cell wall

Ans: (a) Their pigments

14. Eutrophication is often seen in-
(a) Deserts
(b) Fresh water lakes
(c) Oceans
(d) Mountains

Ans: (b) Fresh water lakes

15. Which one of the following green house gases contributes about 20% of the global warming?
(a) CO2
(b) Methane
(c) CFCs
(d) N2O

Ans: (b) Methane

16. If a water body is contaminated with a toxicant, its biomagnification will be more marked in-
(a) Water
(b) Small fishes
(c) Birds
(d) Planktons

Ans: (c) Birds

17. DDT is-
(a) Ani antibiotic
(b) A non-degradable pollutant
(c) A biodegradable pollutant
(d) Not a pollutant

Ans: (b) A non-degradable pollutant

18. Which of the following pollutant is released from the moving motor vehicles?-
(a) NO2
(b) CO
(c) NO
(d) CO2

Ans: (b) CO

19. The main green house gas is-
(a) Ozone
(b) Chlorofluorocarbon
(c) Carbon dioxide
(d) Oxygen

Ans: (c) Carbon dioxide

20. The gas emitted from refrigerator and air condition industries is-
(a) H2O2
(b) CFC
(c) SO2
(d) N2O

Ans: (b) CFC

21. Normal amount of atmospheric carbon dioxide is about-
(a) 0.03%
(b) 0.3%
(c) 0.01%
(d) 0.1%

Ans: (a) 0.03%

22. Which of the following is not a greenhouse gas?
(a) Oxygen
(b) Nitrogen oxide
(c) Methane
(d) Carbon dioxide

Ans: (a) Oxygen

23. The main source of methane in the environment is-
(a) Bacterial decomposition in hot springs
(b) Volcanic eruption
(c) Anaerobic respiration by microorganisms in marshy land
(d) Lightening

Ans: (c) Anaerobic respiration by microorganisms in marshy land

24. Which of the following is fossil fuel?
(a) Methane
(b) Mineral oil
(c) Coal
(d) Both b & c

Ans: (d) Both b & c

25. Gas produced by incomplete oxidation of fossil fuel is-
(a) Hydrogen sulphide
(b) Nitric oxide
(c) Carbon monoxide
(d) Chlorofluorocarbon

Ans: (c) Carbon monoxide

26. A poisonous breath-choking gas is-
(a) Nitrogen
(b) Carbon dioxide
(c) Oxygen
(d) Carbon monoxide

Ans: (d) Carbon monoxide

27. Ozone layer is present in the –
(a) Mesosphere
(b) Stratosphere
(c) Troposphere
(d) Exosphere

Ans: (b) Stratosphere

28. The gas that causes maximum damage to the ozone layer is-
(a) PAN
(b) Carbon monoxide
(c) Carbon dioxide
(d) Chlorofluorocarbon

Ans: (d) Chlorofluorocarbon

29. CFC gas is emitted from-
(a) Oil refineries
(b) Smog
(c) Automobiles
(d) Refrigerator factories

Ans: (d) Refrigerator factories

30. The microorganisms of wetlands produce-
(a) Aerosol
(b) Butane
(c) Methane
(d) Elinver

Ans: (c) Methane

31. The pollutant emitted from foam, mattress factories is-
(a) Lead
(b) PAN
(c) NO
(d) CFC

Ans: (d) CFC

32. The plant part responsible for air pollution is-
(a) Fruit
(b) Pollen grains
(c) Flower
(d) Leaves

Ans: (b) Pollen grains

33. Full name of PAN is –
(a) Para acetyl nitrate
(b) Peroxyacetyl nitrate
(c) Peroxy acid nitrate
(d) Para acedic nitrogen

Ans: (b) Peroxyacetyl nitrate

34. CO2, SO2, and NO are-
(a) Primary pollutant
(b) Secondary pollutant
(c) Teritary pollutant
(d) None of the above

Ans: (a) Primary pollutant

35. PAN, SO3, HNOx are –
(a) Primary pollutant
(b) Secondary frllutonl
(c) Portial pollutant
(d) Not pollutant

Ans: (b) Secondary frllutonl

36. Example of SPM is-
(a) Lead
(b) Pollen grain
(c) Plastic
(d) Aerosol

Ans: (b) Pollen grain

37. Which type of pollution is caused by SPM?
(a) Air pollution
(b) Soil pollution
(c) Sand pollution
(d) Water pollution

Ans: (a) Air pollution

38. The main components of acid rain are-
(a) Hydrochloric acid and hydrofluoric acid
(b) Maleic acid and formic acid
(c) Sulphuric acid and nitric acid
(d) Citric acid and tartaric acid

Ans: (c) Sulphuric acid and nitric acid

39. The gas which is abundant in industrial area is-
(a) Argon
(b) Neon
(c) Oxygen
(d) Sulphur dioxide

Ans: (d) Sulphur dioxide

40. A harmful effect of sulphur dioxide is-
(a) Black spots on skin
(b) Gastric ulcer
(c) Inflammation of respiratory tract
(d) Pancreatic disease

Ans: (c) Inflammation of respiratory tract

41. Natural source of sulphar dioxide is-
(a) Lightening
(b) Chemical factories
(c) Volcanoes
(d) Waterbodies

Ans: (c) Volcanoes

42. Which of the following is the main source of sulphar dioxide in air?
(a) Thermal power plants
(b) Hydro power plants
(c) Atomic power plants
(d) Chemical industries

Ans: (a) Thermal power plants

43. Due to acid rain, maximum damage occurs to-
(a) Wooden houses
(b) Glass wares
(c) Marble scullptures
(d) Porcelain articles

Ans: (c) Marble scullptures

44. The diseases associated with air pollution- [Madhyamik 17]
(a) Diarrhoea, typhoid, hepatitis
(b) Hepatitis, bronchitis, deafness
(c) Bronchitis, asthma, lung cancer
(d) Lung cancer, polio, malaria

Ans: (c) Bronchitis, asthma, lung cancer

45. In undeveloped countries, water pollutes is caused mainly due to-
(a) Human and cattle wastes
(b) Thermal power plants
(c) Industerial by-products
(d) Aromic power plants

Ans: (a) Human and cattle wastes

46. An example of biochemical water pollutant is-
(a) Brick
(b) Sand
(c) Stone
(d) Detergent

Ans: (d) Detergent

47. A water-insoluble pollution is-
(a) Salt
(b) Plastic
(c) Arsenic
(d) Hydrogen sulphide

Ans: (b) Plastic

48. The component of detergent that causes maximum water pollution is-
(a) Alkali
(b) Phosphate
(c) Nitrate
(d) Sulphate

Ans: (b) Phosphate

49. Maximum water pollution is caused by-
(a) Mineral plants
(b) Paper and leather industries
(c) Electronic industries
(d) Steel industries

Ans: (b) Paper and leather industries

50. The recommended PH of drinking water is-
(a) 3.5 to 5.5
(b) 6.5 – 8.5
(c) 15.5-13.5
(d) 9.5-11.5

Ans: (b) 6.5 – 8.5

51. The dissolved O2 of normal water is-
(a) 10 ppm
(b) 8 ppm
(c) 1 ppm
(d) 3 ppm

Ans: (b) 8 ppm

52. The full form of COD is-
(a) Common Oxygen Demand
(b) Common oxygen development
(c) Chemical oxygen demand
(d) Chemical oxygen development

Ans: (c) Chemical oxygen demand

53. COD is measured to know the level of-
(a) Air pollution
(b) Noise pollution
(c) Water pollution
(d) Soil pollution

Ans: (c) Water pollution

54. BOD is used to measure-
(a) Demand of CO2
(b) Demand of hydrogen
(c) Demand of oxygen
(d) Demand of nitrogen

Ans: (c) Demand of oxygen

55. The bacterium used as bio-indicator of water pollution is-
(a) Bacillus subtilis
(b) E. coli
(c) Phizobium leguminasarum
(d) Thiobacillus denitrificans

Ans: (b) E. coli

56. A water borne disease is-
(a) Pox
(b) Hepatitis
(c) Malaria
(d) Measles

Ans: (b) Hepatitis

57. Cholera is a type of –
(a) Air borne disease
(b) Soil-borne disease
(c) Water- borne disease
(d) Protozoan disease

Ans: (c) Water- borne disease

58. Harmful toxin released by algae is-
(a) Neurotoxin
(b) Fibrin
(c) Phyllotoxin
(d) Oxytocin

Ans: (a) Neurotoxin

59. Amoeabiasis and giardiasis are diseases caused by-
(a) Protozoa
(b) Bacteria
(c) Viruses
(d) Algae

Ans: (a) Protozoa

60. The source of underground water pollution is-
(a) Mercury
(b) Cadmium
(c) Fluorine
(d) Arsenic

Ans: (d) Arsenic

61. The aceptable limit of arsenic in drinking water is-
(a) 0.05ppm
(b) 0.09ppm
(c) 0.20 ppm
(d) 0.15ppm

Ans: (a) 0.05ppm

62. Black foot disease is caused by which of the poluutant?
(a) Arsenic
(b) Lead
(c) Cadmium
(d) Mercury

Ans: (a) Arsenic

63. Eutrophication results in the increase of-
(a) Ferns
(b) Mosses
(c) Fungi
(d) Algae

Ans: (d) Algae

64. DDT is a type of-
(a) Organic manure
(b) Biofertiliser
(c) Inorganic fertiliser
(d) Insecticide

Ans: (d) Insecticide

65. An insecticide available from plants is-
(a) BHC
(b) Pyrethin
(c) Lindane
(c) Malathion

Ans: (b) Pyrethin

66. Application of urea fertilisers, supplements the need of-
(a) Nitrogen
(b) Phosphorus
9c) Copper
(d) Sulphar

Ans: (a) Nitrogen

67. A non-biodegradable substance is-
(a) Wood
(b) Paper
(c) Plastic
(d) Leather

Ans: (c) Plastic

68. The intensity of electric airhorn is about-
(a) 40db
(b) 140db
(c) 70db
(d) 100db

Ans: (b) 140db

69. The intensity of sound that causes physiological disorder is-
(a) 45-55 db
(b) 60-70 db
(c) 80-90 db
(d) 35-45 db

Ans: (c) 80-90 db

70. Which of the following is associated with biomagnification-
(a) Detergent
(b) CFe
(c) DDT
(d) Phosphate

Ans: (c) DDT

2. Very short-type questions and answers

2A. Fill in the blanks

1. The entire inhabited part of the earth where living organisms exist along with the abiotic environment is called ___________________. (Biosphere)
2. The materials which cause pollution of the environment are called ___________. (Pollutants)
3. Major cause of air pollution in big cities is _______________. (Automobile exhaust)
4. From refrigeration industry __________ is evoloved. (CFC)
5. ___________ is a nitrogenous greenhouse gas. (Nitrous oxide)
6. Cholera is accused by the __________ bacterium. (Vibrio cholerae)
7. The pathogen causing amoebiasis is ___________. (Entamoeba histolytica)
8. Mixing of arsenic with groundwater causes __________ disease. (Black foot)
9. In ____________ disease, blisters and black marks are seen on palms and feet. (Arsenicosis)
10. To produce the bottled cold drinks widely sold in the market, a lot of ___________ water is wasted. [Madhyamik 20] (Groundwater)
11. The soil-dwelling microbes are called ____________ microbes. (Edaphic)
12. Paris green is an ____________ pesticide. (Inorganic)
13. Sodium arsenite is a __________. (Herbicide)
14. ___________ is an insecticide that causes soil pollution. (DDT)
15. Soil pollutants enter into human body by direct ___________. (Contact)
16. Fungal spores of Aspergillus mostly effect the ____________ system of human and poultry. (Respiratory)
17. Aspergillus causes a lung disease called ___________. (Aspergillosis)
18. Clostridium tetani is an _______ bacterium that causes tetanus. (Anaerobic)
19. ________________ is a disease caused due to soil pollution. (Tetanus)
20. A soil-dwelling worm is ___________. (Earthworm)
21. The pathogen of anthrax is a _____________ bacteria. (Bacillus)
22. In india, the admissible level of intensity of sound in industrial area is ___________. (75 dB)
23. High intensity sound ____________ heart rate. (Increases)
24. An inflammable greenhouse gas produced from paddy fields is _________. [Madhyamik 17] (Methane)
25. The fine droplets of smokes, ashes, dusts, pollen grains, etc. suspended in air collectively called ________, which cause various lung disease. [Madhyamik 18] (SPM)
26. The air-brone particulate matters less than a diameter of __________ are called aerosols. (1 micrometre)
27. ___________ gas is produced due to the decomposition of garbage. (Methane)
28. The PH of water bodies ___________ after acid rain. (Decreases)
29. The architectures built of __________ and limestone are damaged by acid rain. (Marble)
30. SO2, NOx, increase the occurrence of ___________ among people living in industrial area. (Respiratory diseases)
31. A respiratory disease caused due to air pollution is __________. (Asthma)
32. The miners of coal mine often develop __________ disease. (Black lung)
33. The disease caused due to squeezing of the trachea is called __________. (Asthma)
34. DDT is an ___________ pesticide. (Organochlorine)
35. ____________ is a toxic material released by algae. (Neurotoxin)

2B. True or false

1. Methane is a greenhouse gas. (True)
2. O3 is used in aerosol spray. (False)
3. Acid rain is caused by SO2 and NO2 gases formed due to air pollution. (True)
4. The Taj Mahal is adversely affected by acid rain. (True)
5. Black lung disease is a water borne disease. (False)
6. Aldrin is an inorganic pesticide. (False)
7. High fever is significant symptom of cholera. (False)
8. Arsenicosis is caused due to mercury pollution. (False)
9. Amoebiasis is caused by the infection of Entamoeba. (True)
10. Neurotoxin is usually secreted by fungi. (False)
11. Algal bloom indicates the high growth of algae. (True)
12. Bacillus anthracis is a water borne bacterium. (False)
13. Echinococcus is a type of fungus. (False)
14. Toxic pollutants generally accumulate in the adipose tissue of animal. (True)
15. Ascaris is a type of round worm. (True)
16. Noise pollution is the second most dangerous polluting hazard. (True)
17. CPCB has laid down the permissible sound intensity level at 40 db for the motor vehicles. (False)
18. A sound of more than 150 db caused by firecrackers may lead to acoustic trauma. (True)

2C. Match the column

Column A	Column B
1. Air pollution	A. Sound of fire
2. Water pollutant	B. Carbon dioxide
3. Noise pollution	C. Inorganic pesticide
4. Soil pollution	D. Nitrifying bacteria
5. Conversion of ammonia to nitrate	E. Agricultural waste
6. Edaphic pathogens	F. Denitrifying bacteria
	G. Soil pollution

Ans:

Column A	Column B
1. Air pollution	B. Carbon dioxide
2. Water pollutant	E. Agricultural waste
3. Noise pollution	A. Sound of fire
4. Soil pollution	C. Inorganic pesticide
5. Conversion of ammonia to nitrate	D. Nitrifying bacteria
6. Edaphic pathogens	G. Soil pollution

Column A	Column B
1. CO2	A. Used in aerosol spray
2. CFC	B. Cause of acid rain
3. NO2	C. Organic pesticide
4. CH4	D. Produced by combustion of fossil fuel
5. PAN	E. Produced by decomposition of organic matters
6. DDT	F. Inorganic weedicide
	G. Secondary pollutant

Ans:

Column A	Column B
1. CO₂	D. Produced by combustion of fossil fuel
2. CFC	A. Used in aerosol spray
3. NO₂	B. Cause of acid rain
4. CH₄	E. Produced by decomposition of organic matters
5. PAN	G. Secondary pollutant
6. DDT	C. Organic pesticide

2D. Single word questions and answers

1. What do you mean by environmental pollution?
Ans: Environmental pollution means the mixing of harmful substances with air, water and soil by harmful substances which adversely affect living organisms and natural resources.

2. What is phytoplankton?
Ans: Phytoplankton are microscopic, floating, photosynthetic organisms found in water bodies which form the primary producers of aquatic ecosystems.

3. What is zooplankton?
Ans: Zooplankton are microscopic, floating animal organisms present in water that feed on phytoplankton.

4. Name two pollutants.
Ans: Smoke and pesticides are two common pollutants.

5. Mention the full name of CFC.
Ans: The full name of CFC is Chlorofluorocarbon.

6. What is water pollution?
Ans: Water pollution is the contamination of water bodies by harmful substances which make water unfit for use by living organisms.

7. What is solid waste?
Ans: Solid waste refers to unwanted and discarded solid materials produced by human activities.

8. State the expanded form of DDT.
Ans: DDT stands for Dichloro-diphenyl-trichloroethane.

9. Give a definition of ecosystem.
Ans: An ecosystem is a functional unit of nature where living organisms interact with each other and with their physical environment.

10. What is biosphere?
Ans: The biosphere is the zone of the Earth where life exists, including land, water and air.

11. Define pollution.
Ans: Pollution is the undesirable change in the physical, chemical or biological quality of the environment.

12. What do you mean by biomagnification?
Ans: Biomagnification is the gradual increase in the concentration of toxic substances at successive levels of a food chain.

13. What do you mean by greenhouse effect?
Ans: The greenhouse effect is the warming of the Earth due to trapping of heat by certain gases in the atmosphere.

14. What is algal bloom?
Ans: Algal bloom is the excessive growth of algae in water bodies due to nutrient enrichment.

15. What is water pollution?
Ans: Water pollution is the contamination of water with harmful substances that degrade its quality.

16. Which substances cause maximum air pollution?
Ans: Carbon monoxide, sulphur dioxide and nitrogen oxides cause maximum air pollution.

17. Name two greenhouse gases.
Ans: Carbon dioxide and methane are greenhouse gases.

18. Which are the main sources of air-polluting hydrocarbons?
Ans: Automobiles and oil refineries are the main sources of air-polluting hydrocarbons.

19. Which are the two main air pollutants in urban cities?
Ans: Carbon monoxide and suspended particulate matter are the main air pollutants.

20. What is the main cause of air pollution in metro cities?
Ans: Vehicular emission is the main cause of air pollution in metro cities.

21. What is fly ash?
Ans: Fly ash is the fine particulate residue produced during the combustion of coal in thermal power plants.

22. What is the name of the gas responsible for the Bhopal gas tragedy?
Ans: Methyl isocyanate gas was responsible for the Bhopal gas tragedy.

23. Name the fine particulate matter liberated due to incomplete combustion of petroleum.
Ans: Suspended particulate matter (SPM) is liberated due to incomplete combustion.

24. How does SPM cause harm to human respiration?
Ans: SPM enters the lungs and damages respiratory tissues, causing breathing problems.

25. Which pollutant of automobile exhaust prevents haemoglobin formation?
Ans: Carbon monoxide prevents haemoglobin formation.

26. Name a symbiotic association that acts as a bio-indicator of air pollution.
Ans: Lichen acts as a bio-indicator of air pollution.

27. Which pollutant reduces chlorophyll content in green plants?
Ans: Sulphur dioxide reduces chlorophyll content in plants.

28. Name two gases responsible for acid rain.
Ans: Sulphur dioxide and nitrogen dioxide are responsible for acid rain.

29. Name two famous architectures in India vulnerable to acid rain.
Ans: The Taj Mahal and Victoria Memorial are vulnerable to acid rain.

30. Which gas is emitted during volcanic eruption?
Ans: Sulphur dioxide is emitted during volcanic eruption.

31. What is the full form of COPD?
Ans: COPD stands for Chronic Obstructive Pulmonary Disease.

32. Mention two adverse effects of carbon monoxide on human health.
Ans: It reduces oxygen transport in blood and causes headache and dizziness.

33. Name a gas which causes lung cancer.
Ans: Radon gas causes lung cancer.

34. Name the harmful component that enters the lungs during smoking.
Ans: Nicotine enters the lungs during smoking.

35. Which disease often occurs among coal miners?
Ans: Pneumoconiosis often occurs among coal miners.

36. Name three main types of insecticides.
Ans: Organochlorine, organophosphate and carbamate insecticides.

37. What is the full form of DDT?
Ans: DDT stands for Dichloro-diphenyl-trichloroethane.

38. Name two organochlorine insecticides.
Ans: DDT and BHC are organochlorine insecticides.

39. What is sewage?
Ans: Sewage is wastewater containing human excreta and other domestic wastes.

40. Name two water-insoluble bio-pollutants.
Ans: DDT and mercury are water-insoluble bio-pollutants.

41. Name two water-borne viral diseases.
Ans: Hepatitis A and polio are water-borne viral diseases.

42. Name two water-borne bacterial diseases.
Ans: Cholera and typhoid are water-borne bacterial diseases.

43. Name two water-borne protozoan diseases.
Ans: Amoebiasis and giardiasis are water-borne protozoan diseases.

44. Name two water-borne helminthic diseases.
Ans: Ascariasis and filariasis are water-borne helminthic diseases.

45. Name the bacterium which causes typhoid.
Ans: Salmonella typhi causes typhoid.

46. Name the bacterium which causes cholera.
Ans: Vibrio cholerae causes cholera.

47. Name two harmful toxins produced by algae.
Ans: Saxitoxin and anatoxin are harmful algal toxins.

48. What depth of a tube well is unlikely to contain arsenic?
Ans: Tube wells deeper than 300 metres are unlikely to contain arsenic.

49. What is the acceptable limit of fluorine in drinking water in India?
Ans: The acceptable limit of fluorine is 1 mg per litre.

50. Which salt is predominant in seawater?
Ans: Sodium chloride is the predominant salt in seawater.

51. When does eutrophication occur?
Ans: Eutrophication occurs when excess nutrients enter water bodies.

52. What happens to dissolved oxygen during eutrophication?
Ans: The level of dissolved oxygen decreases.

53. Name two fertilisers responsible for eutrophication.
Ans: Nitrate and phosphate fertilisers cause eutrophication.

54. Which disease is caused due to cadmium pollution?
Ans: Itai-itai disease is caused by cadmium pollution.

55. Which worms contaminate soil after leaving the human body?
Ans: Ascaris worms contaminate soil.

56. What is the full form of NIHL?
Ans: NIHL stands for Noise-Induced Hearing Loss.

57. Name the sound-receiving structure of the ear.
Ans: The pinna is the sound-receiving structure.

58. Name the worm that causes ascariasis.
Ans: Ascaris lumbricoides causes ascariasis.

59. What happens when excess nitrogenous fertilisers are added to fields?
Ans: Excess fertilisers cause soil and water pollution.

60. What happens when excessive irrigation is done on crop fields?
Ans: Excessive irrigation leads to waterlogging and reduced soil fertility.

3. Short-type questions and answers

1. What do you mean by biomagnification?
Ans: Biomagnification is the process by which harmful chemicals like pesticides and heavy metals increase in concentration as they move from one level of the food chain to the next. These chemicals enter the body of small organisms and finally reach higher animals and humans causing serious health problems.

2. Mention the differences between pollution and pollutants.
Ans:

Pollution	Pollutants
Pollution is the harmful change in the environment.	Pollutants are the substances that cause harm to the environment.
It is a condition or effect of environmental damage.	They are the cause of environmental damage.
Pollution affects air, water, and soil.	Pollutants may be smoke, chemicals, sewage, etc.
Pollution harms living organisms and natural resources.	Pollutants are responsible for health and environmental problems.

3. What do you mean by anthropogenic pollution and natural pollution?
Ans: Anthropogenic pollution is caused by human activities such as industrial waste, vehicles and burning of fuels. Natural pollution occurs due to natural causes like volcanic eruptions, forest fires and dust storms.

4. What is afforestation?
Ans: Afforestation is the practice of planting trees on barren land or areas where forests have been destroyed. It helps in maintaining ecological balance, reducing pollution and conserving wildlife.

5. What is greenhouse effect? What are its consequences?
Ans: The greenhouse effect is the trapping of heat in the Earth’s atmosphere by gases like carbon dioxide and methane, so the temperature of the Earth increases, causing global warming, melting of ice caps, rise in sea level and climate change.

6. Mention three causes of deforestation.
Ans: The three causes of deforestation are:

Construction of roads, houses, and industries
Cutting of trees for timber and fuel
Clearing of forests for agricultural land

7. What is environmental pollution?
Ans: Environmental pollution is the contamination of air, water and soil by harmful substances that negatively affect living organisms and natural resources.

8. What is pollutants?
Ans: Pollutants are unwanted and harmful substances released into the environment that cause pollution and damage to living beings.

9. What is greenhouse effect?
Ans: The greenhouse effect is a natural process in which certain gases trap heat in the atmosphere and keep the Earth warm.

10. What are primary air pollutants?
Ans: Primary air pollutants are harmful substances that are directly released into the air from sources like vehicles and factories. Examples include carbon monoxide and sulphur dioxide.

11. What are secondary air pollutants?
Ans: Secondary air pollutants are formed in the atmosphere by chemical reactions between primary pollutants. Examples include ozone and PAN.

12. What is non-biodegradable pollutants?
Ans: Non-biodegradable pollutants are substances that do not decompose naturally and remain in the environment for a long time, causing pollution. Plastics and pesticides are examples.

13. What is bio-degradable pollutants?
Ans: Biodegradable pollutants are substances that can be broken down by microorganisms into simpler harmless substances. Food waste and paper are examples.

14. Write harmful effects of ozone hole.
Ans: The ozone hole allows harmful ultraviolet rays to reach the Earth. These rays can cause skin cancer, eye damage, weakened immunity and reduced crop productivity.

15. What is ozone hole?
Ans: Ozone hole is the thinning of the ozone layer in the stratosphere, mainly caused by CFCs.

16. How is PAN produced in the atmosphere?
Ans: PAN is produced in the atmosphere when hydrocarbons react with nitrogen oxides in the presence of sunlight.

17. What are harmful effects of SPM?
Ans: SPM enters the lungs during breathing and causes respiratory diseases like asthma, bronchitis and lung damage.

18. What is smog?
Ans: Smog is a mixture of smoke and fog formed due to air pollution. It reduces visibility and causes irritation in eyes and breathing problems.

19. How does acid rain cause damage to Taj Mahal?
Ans: Acid rain damages the Taj Mahal by reacting with its marble. The acids present in rain slowly corrode the marble surface, causing yellowing, black spots, and loss of shine. Over time, this reaction weakens the structure and spoils the beauty of the monument.

20. Mention two causes of increase in carbon dioxide level in the atmosphere?
Ans: The two causes of increase in carbon dioxide level in the atmosphere are:

Cutting down of forests (deforestation)
Burning of fossil fuels like coal, petrol, and diesel

21. What is water pollution?
Ans: Water pollution is the condition in which harmful substances like sewage, chemicals, and wastes mix with rivers, lakes, and oceans. As a result, the water becomes dirty, unsafe, and unfit for use by humans, animals, and plants.

22. Mention two causes of water pollution?
Ans: The two causes of water pollution are:

Discharge of industrial wastes into rivers and lakes
Disposal of untreated sewage into water bodies

23. What is algal bloom?
Ans: Algal bloom is the rapid and excessive growth of algae in rivers, lakes, or ponds. It occurs when excess nutrients like nitrates and phosphates enter the water, making the water green, dirty, and harmful for aquatic life.

24. Mention few characteristic features of eutrophic water bodies?
Ans: The characteristic features of eutrophic water bodies are:

Presence of excess nutrients like nitrates and phosphates
Dense growth of algae (algal bloom)
Foul smell of water
Very low amount of dissolved oxygen

25. What is COD? Mention its significance.
Ans: COD stands for Chemical Oxygen Demand. It shows the amount of oxygen needed to break down chemical pollutants present in water. A high COD value indicates high level of water pollution.

26. What are effects of soil pollution?
Ans: Soil pollution reduces soil fertility, lowers crop production, and harms useful soil organisms like earthworms. It also allows harmful chemicals to enter the food chain.

27. What is audible sound?
Ans: Audible sound is the sound that can be heard by the human ear. Its frequency range is 20 Hz to 20,000 Hz.

28. What is acoustic trauma?
Ans: Acoustic trauma is damage to the ear caused by sudden or very loud sound, such as explosions or firecrackers, which may lead to hearing loss.

29. What is silence zone?
Ans: A silence zone is an area where use of loud sound is restricted to maintain peace. Examples include hospitals, schools, courts, and libraries.

30. What is masking effect?
Ans: Masking effect occurs when a loud sound covers or hides a softer sound, making it difficult to hear the softer sound clearly.

4. Long-type questions and answers

1. Classify the pollutants with the help of a chart.
Ans: Pollutants are substances that contaminate the environment and cause harm to living organisms. On the basis of their nature and origin, pollutants can be classified as follows:

Basis	Types of Pollutants	Examples
Nature	Biodegradable	Sewage, food waste
	Non-biodegradable	Plastics, pesticides
Source	Natural pollutants	Volcanic ash, pollen
	Man-made pollutants	Smoke, industrial waste
Formation	Primary pollutants	CO, SO₂
	Secondary pollutants	Ozone, smog

2. Give an account of pollutants of air pollution.
Ans: Air pollutants are harmful substances present in the atmosphere in excess amount. Major air pollutants include carbon monoxide, sulphur dioxide, nitrogen oxides, hydrocarbons, particulate matter, and chlorofluorocarbons. These pollutants mainly come from vehicles, industries, burning of fossil fuels, and forest fires. Carbon monoxide reduces oxygen supply in blood. Sulphur dioxide and nitrogen oxides cause acid rain. Particulate matter damages lungs. Thus, air pollutants seriously affect human health and environment.

3. How is water polluted? Discuss the harmful effects of water pollution.
Ans: Water pollution occurs when harmful substances enter rivers, lakes, ponds, or groundwater. Major causes are discharge of domestic sewage, industrial effluents, agricultural runoff containing fertilizers and pesticides, and dumping of wastes. Harmful effects include spread of water-borne diseases like cholera and typhoid, death of aquatic organisms due to lack of oxygen, eutrophication, and accumulation of toxic substances in food chains. Hence, water pollution affects both human health and aquatic life.

4. Discuss the greenhouse effect on the biological system.
Ans: The greenhouse effect is the warming of the earth due to trapping of heat by greenhouse gases like carbon dioxide and methane. Moderate greenhouse effect is necessary for life. However, excessive greenhouse effect causes global warming. It leads to melting of glaciers, rise in sea level, changes in climate, loss of biodiversity, and disturbance in ecosystems. Crops and animals are also affected due to temperature imbalance.

5. Write about the sources and nature of pollutants of water.
Ans: Sources of water pollutants include domestic sewage, industrial waste, agricultural runoff, oil spills, and thermal discharge. The nature of water pollutants may be physical, chemical, or biological. Physical pollutants include suspended solids; chemical pollutants include acids, heavy metals, fertilizers, and pesticides; biological pollutants include bacteria and viruses. These pollutants degrade water quality and make it unfit for use.

6. Write about the effects of water pollution.
Ans: Water pollution causes depletion of dissolved oxygen leading to death of fishes. It spreads diseases like dysentery and hepatitis. Toxic chemicals accumulate in aquatic organisms causing biomagnification. Eutrophication results in excessive growth of algae. Drinking polluted water affects kidneys, liver, and nervous system. Thus, water pollution is harmful to life.

7. Mention the basic groups of pesticide chemicals with two examples for each.
Ans:

Group	Examples
Organochlorines	DDT, BHC
Organophosphates	Malathion, Parathion
Carbamates	Carbaryl, Aldicarb
Pyrethroids	Permethrin, Cypermethrin

8. Speculate the probable causes of the following phenomena. [Madhyamik 20]
Ans: Insomnia, high blood pressure, and deafness are caused by noise pollution. Decrease in dissolved oxygen and floating of dead fishes occur due to water pollution and eutrophication. Decrease in the number of crocodiles is due to water pollution and destruction of habitat. Inflammation of the respiratory tract is caused by air pollution from smoke and harmful gases. Decrease in pollinating insects is due to excessive use of pesticides, which kills beneficial insects.

9. Write about the causes of global warming.
Ans: Global warming is mainly caused by the increase of greenhouse gases in the atmosphere. Burning of fossil fuels such as coal, petrol, and diesel in industries, power plants, and vehicles releases large amounts of carbon dioxide. Deforestation reduces the number of trees that absorb carbon dioxide, leading to its accumulation in air. Agricultural activities, paddy fields, and digestion in cattle increase methane gas. Use of CFCs in refrigerators and air conditioners also contributes to global warming. These factors increase the greenhouse effect and raise the average temperature of the earth.

10. What strategies may be taken to check global warming?
Ans: Global warming can be checked by reducing the use of fossil fuels and switching to renewable sources like solar and wind energy. Afforestation and prevention of deforestation help reduce carbon dioxide levels. Use of public transport and fuel-efficient vehicles lowers greenhouse gas emission. Industries should control harmful gas release using pollution-control devices. Use of CFC-free appliances must be encouraged. Energy conservation, waste management, and public awareness are also important steps to control global warming.

11. What is deforestation? Mention the causes and effects of deforestation.
Ans: Deforestation means the large-scale cutting and clearing of forest trees. The main causes are expansion of agriculture, urbanisation, industrial development, construction of roads and houses, and cutting trees for fuel and timber. Deforestation causes soil erosion, floods, and loss of soil fertility. It leads to loss of wildlife and biodiversity. Increase of carbon dioxide in the atmosphere results in climate change and global warming. Thus, deforestation disturbs the ecological balance.

12. Discuss briefly the greenhouse effect.
Ans: The greenhouse effect is a natural process by which certain gases like carbon dioxide, methane, and water vapour trap heat in the earth’s atmosphere. This process keeps the earth warm enough to support life. However, due to human activities, the amount of greenhouse gases has increased excessively. This causes abnormal rise in temperature, known as global warming. As a result, climate change, melting of glaciers, and rise in sea level occur, affecting life on earth.

13. How are water and air polluted?
Ans: Air pollution occurs due to smoke and harmful gases released from vehicles, industries, burning of fossil fuels, and chemical factories. Dust, particulate matter, and toxic gases pollute the atmosphere.
Water pollution occurs when sewage, industrial wastes, agricultural chemicals, and oil spills enter rivers, lakes, and oceans. Both air and water pollution harm living organisms, damage ecosystems, and cause various diseases.

14. Write about global warming gases.
Ans: Global warming gases, also called greenhouse gases, are the gases present in the atmosphere that trap heat radiated from the earth’s surface and increase atmospheric temperature. The major global warming gases are carbon dioxide (CO₂), methane (CH₄), nitrous oxide (N₂O), chlorofluorocarbons (CFCs), and ozone (O₃). Carbon dioxide is released mainly from burning of fossil fuels and deforestation. Methane is produced from paddy fields, cattle digestion, landfills, and decomposition of organic matter. Nitrous oxide comes from agricultural activities and fertilizers. CFCs are released from refrigerators, air conditioners, and aerosol sprays. Excessive increase of these gases leads to global warming and climate change.

15. Mention the different types of pollution. [Madhyamik 18]
Ans: The different types of pollution are air pollution, water pollution, soil pollution, noise pollution, thermal pollution, and radioactive pollution. Air pollution occurs due to harmful gases and particulate matter in the atmosphere. Water pollution results from sewage, industrial waste, and chemicals mixing with water bodies. Soil pollution is caused by pesticides, fertilizers, and solid wastes. Noise pollution is produced by loud sounds from vehicles, industries, and machines. Thermal pollution is caused by discharge of hot water from power plants, and radioactive pollution occurs due to radioactive substances. All types of pollution harm the environment and human health.

16. Briefly explain the effects of acid rain on environment. [Madhyamik 17]
Ans: Acid rain is formed due to sulphur dioxide and nitrogen oxides present in the atmosphere. Acid rain damages crops, forests, and soil fertility by increasing soil acidity. It acidifies lakes and rivers, resulting in death of fishes and other aquatic organisms. Acid rain also causes corrosion of buildings, monuments, and marble structures like the Taj Mahal. In addition, acid rain affects human health by causing irritation and respiratory problems.

17. How does the amount of methane increase in the atmosphere? [Madhyamik 17,19]
Ans: The amount of methane in the atmosphere increases due to several natural and human activities. Methane is produced during anaerobic decomposition of organic matter in marshy lands and wetlands. Paddy cultivation releases methane due to waterlogged conditions. It is also produced from digestion in cattle, landfills, sewage treatment plants, and leakage from natural gas pipelines. Methane is a powerful greenhouse gas and contributes significantly to global warming.

18. State the causes of water pollution. [Madhyamik 17]
Ans: Water pollution is caused mainly by discharge of untreated domestic sewage into rivers and lakes. Industrial effluents containing harmful chemicals and heavy metals also pollute water. Agricultural runoff carrying fertilizers and pesticides enters water bodies and causes eutrophication. Oil spills, dumping of solid wastes, and thermal discharge from industries further degrade water quality. These causes make water unsafe for drinking and aquatic life.

19. Evaluate the effects of pollutants on environment and human health. [Madhyamik 20]
Ans: Non-biodegradable insecticides like DDT accumulate in the food chain and cause serious health hazards such as nerve damage. Pollen grains cause allergies and respiratory problems. Chemical fertilizers containing nitrates and phosphates lead to eutrophication, reducing dissolved oxygen in water. Pathogenic wastes from hospitals spread infectious diseases. Chlorofluorocarbons damage the ozone layer, allowing harmful UV rays to reach the earth, causing skin cancer and eye disorders.

20. What are the harmful impacts of sound pollution on ears and heart? [Madhyamik 18]
Ans: Sound pollution has serious effects on the ears and heart. Continuous exposure to loud sound causes hearing loss, tinnitus, and partial or complete deafness. Sudden loud sound may result in acoustic trauma. Noise pollution increases blood pressure and heart rate, leading to heart diseases. It also causes stress, irritation, insomnia, and mental fatigue, affecting overall health.