NEET AIPMT Biology Chapter Wise Solutions – Environmental Issues
1. Acid rain is caused by increase in the atmospheric concentration of
(a) CO2 and CO
(b) O3 and dust
(c) SO2 and NO2
(d) SO3 and CO. (AIPMT 2015)
2. Eutrophication of water bodies leading to killing of fishes is mainly due to non-availability of
(a) essential minerals
(d) light. (AIPMT 2015)
3. The UN Conference of Parties on climate change in the year 2012 was held at
(d) Doha. (AIPMT 2015)
4. Which of the following are most suitable indicators of S02 pollution in the environment?
(d) Conifers (AIPMT 2015)
5. Increase in concentration of the toxicant at successive trophic levels is known as
(b) biogeochemical cycling
(d) biodeterioration. (AIPMT 2015)
6. The UN Conference of Parties on climate change in the year 2011 was held in
(d) South Africa. (AIPMT 2015, Cancelled)
7. Which of the following is not one of the prime health risks associated with greater UV radiations through the atmosphere due to depletion of stratospheric ozone?
(a) Damage to eyes
(b) Increased liver cancer
(c) Increased skin cancer
(d) Reduced Immune System. (AIPMT 2015, Cancelled)
8. High value of BOD (Biochemical Oxygen Demand) indicates that
(a) water is less polluted
(b) consumption of organic matter in the water is higher by the microbes
(c) water is pure
(d) water is highly polluted. (AIPMT 2015, Cancelled)
9. Rachel Carson’s famous book “Silent Spring” is related to
(a) population explosion
(b) ecosystem management
(c) pesticide pollution
(d) noise pollution. (AIPMT 2015, Cancelled)
10. A location with luxuriant growth of lichens on the trees indicates that the
(a) trees are very healthy
(b) trees are heavily infested
(c) location is highly polluted
(d) location is not polluted. (AIPMT 2014)
11. The zone of atmosphere in which the ozone layer is present is called
(d) troposphere. (AIPMT 2014)
12. A scrubber in the exhaust of a chemical industrial plant removes
(a) gases like sulphur dioxide
(b) particulate matter of the size 5 micrometer or above
(c) gases like ozone and methane
(d) particulate matter of the size 2.5 micrometer or less. (AIPMT 2014 )
13. Kyoto protocol was endorsed at
(d) CoP-5. (NEET 2013)
14. Global warming can be controlled by
(a) increasing deforestation, slowing down the growth of human population
(b) increasing deforestation, reducing efficiency of energy usage
(c) reducing deforestation, cutting down use of fossil fuel
(d) reducing reforestation, increasing the use of fossil fuel. (NEET2013)
15. The Air Prevention and Control of Pollution Act came into force in
(d) 1981. (NEET 2013)
16. The second commitment period for Kyoto Protocol was decided at
(d) Cancun. (Karnataka NEET 2013)
17. Climate of the world is threatened by
(a) decreasing amount of atmospheric oxygen
(b) increasing amount of atmospheric carbon dioxide
(c) decreasing amount of atmospheric carbon dioxide
(d) increasing concentration of atmospheric oxygen. (Karnataka NEET 2013)
18. Which one of the following is not correct with regard to the harmful effects of particulate matter of the size 2.5 micro meters or less?
(a) It can cause respiratory problems.
(b) It can directly enter into our circulatory system.
(c) It can cause inflammation and damage to the lungs.
(d) It can be inhaled into the lungs. (Karnataka NEET 2013)
19. In an area where DDThad been used extensively, the population of birds declined significantly because
(a) birds stopped laying eggs
(b) earthworms in the area got eradicated
(c) cobras were feeding exclusively on birds
(d) many of the birds eggs laid, did not hatch. (Prelims 2012)
20. Which one of the following is a wrong statement?
(a) Most of the forests have been lost in tropical areas.
(b) Ozone in upper part of atmosphere is harmful to animals.
(c) Greenhouse effect is a natural phenomenon.
(d) Eutrophication is a natural phenomenon in freshwater bodies. (Prelims 2012)
21. Measuring Biochemical Oxygen Demand (BOD) is a method used for
(a) estimating the amount of organic matter in sewage water
(b) working out the efficiency of oil driven automobile engines
(c) measuring the activity oiSaccharomyces cerexis iae in producing curd on a commercial scale
(d) working out the efficiency of RBCs about their capacity to carry oxygen. (Prelims 2012)
22. Eutrophication is often seen in
(b) fresh water lakes
(d) mountains. (Prelims 2011)
23. Which one of the following pairs of gases are the major cause of “greenhouse effect”?
a) CO2, and O3
(b) CO2, and CO
(c) CFCs and SO2
(d) CO2, and N2. (Prelims 2011)
24. Which one of the following statements is incorrect in case of Bhopal tragedy?
(a) methyl isocyanate gas leakage took place
(b) thousands of human beings died
(c) radioactive fall out engulfed Bhopal
(d) it took place in the night of December 2/3,1984. (Prelims 2011)
25. Which one of the following is correct expanded form of the acronym?
(a) IPCC = International Panel for Climate Change
(b) UNEP = United Nations Environmental Policy
(c) EPA = Environmental Pollution Agency
(d) IUCN = International Union for Conservation of Nature and Natural Resources. (Prelims 2011)
26. “Good ozone” is found in the
(d) ionosphere. (Mains 2011)
21. A renewable exhaustible natural resource is
(d) forest. (Prelims 2010)
28. dB is a standard abbreviation used for the quantitative expression of
(a) the density of bacteria in a medium
(b) a particular pollutant
(c) the dominant Bacillus in a culture
(d) a certain pesticide. (Prelims 2010)
29. The two gases making highest relative contribution to the greenhouse gases are
(a) CO2 and CH4
(b) CH4 and N2O
(c) CFCs and N2O
(d) CO2 and N2O. (Prelims 2010)
30. When domestic sewage mixes with river water
(a) small animals like rats will die after drinking river water
(b) the increased microbial activity releases micronutrients such as iron
(c) the increased microbial activity uses up dissolved oxygen
(d) the river water is still suitable for drinking as impurities are only about 0.1% (Mains 2010)
31. Global agreement in specific control strategies to reduce the release of ozone depleting substances, was adopted by
(a) Montreal Protocol
(b) Kyoto Protocol
(c) Vienna Convention
(d) Rio de Janeiro Conference. (Prelims 2009)
32. Biochemical oxygen demand (BOD) in a river water
(a) has no relationship with concentration of oxygen in the water
(b) gives a measure of Salmonella in the water
(c) increases when sewage gets mixed with river water
(d) remains unchanged when algal bloom occurs. (Prelims 2009)
33. Steps taken by the Government of India to control air pollution include
(a) compulsory PUC (Pollution under control) certification of petrol driven vehicles which tests for carbon monoxide and hydrocarbons
(b) permission to use only pure diesel with a maximum of 500 ppm sulphur as fuel for vehicles
(c) use of non-polluting compressed natural gas (CNG) only as fuel by all buses and trucks
(d) compulsory mixing of 20% ethyl alcohol with petrol and 20% biodiesel with diesel. (Prelims 2009)
34. Montreal Protocol aims at
(a) biodiversity conservation
(b) control of water pollution
(c) control of CO, emission
(d) reduction of ozone depleting substances. (Prelims 2009)
35. DDT residues are rapidly passed through food chain causing biomagnification because DDT is
(a) moderately toxic
(b) non-toxic to aquatic animals
(c) water soluble
(d) lipo soluble. (Prelims 2009)
36. Chipko movement was launched for the protection of
(d) grasslands. (Prelims 2009)
37. A lake near a village suffered heavy mortality of fishes within a few days. Consider the following reasons for this.
(A) lots of urea and phosphate fertilizer were used in the crops in the vicinity
(B) the area was sprayed with DDT by an aircraft
(C) the lake water turned green and stinky
(D) phytoplankton populations in the lake declined initially there by greatly reducing photosynthesis.
Which two of the above were the main causes of fish mortality in the lake?
(a) A, C
(b) A, B
(c) B, C .
(d) C, D. (Prelims 2008)
38. According to Central Pollution Control Board (CPCB), which particulate size in diameter (in micrometers) of the air pollutants is responsible for greatest harm to human health?
(a) 1.0 or less
(c) 2.5 or less
(d) 1.5 or less. (Prelims 2008)
39. Which one of the following is the correct percentage of the two (out of the total of 4) green house gases that contribute to the total global warming?
(a) N2O I6%, CO286%
(b) methane 20%, N2O 18%
(c) CFCs 14%, methane 20%
(d) CO2 40%, CFCs 30%. (Prelims 2008)
40. In which one of the following the BOD (Biochemical Oxygen Demand) of sewage (S), distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE) have been arranged in ascending order?
(d) SE < S < PE < DE. (2007)
41. In a coal fired power plant electrostatic precipitators are installed to control emission of
42. Which one of the following statements is correct?
(a) Both Azotobacter and Rhizobium fix atmospheric nitrogen in root nodules of plants.
(b) Cyanobacteria such as Anabaena and Nos toe are important mobilizers of phosphates and for plant nutrition in soil
(c) At present it is not possible to grow maize without chemical fertilizers
(d) Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies. (2007)
43. Which one of the following is not a bioindicator of water pollution?
(b) stone flies
(c) sewage fungus
(d) sludge-worms. (2007)
44. Limit of BOD prescribed by Central Pollution Control Board for the discharge of industrial and municipal waste waters into natural surface waters, is
(a) <30 ppm
(b) <3.0 ppm
(c) <10 ppm
(d) <100 ppm. (2006)
45. Photochemical smog pollution does not contain
(a) PAN (peroxy acyl nitrate)
(c) nitrogen dioxide
(d) carbon dioxide. (2006)
46. Montreal protocol which calls for appropriate action to protect the ozone layer from human activities was passed in the year
(d) 1988. (2006)
47. Prolonged liberal irrigation of agricultural fields is likely to create the problem of
(d) metal toxicity. (2005)
48. Which one of the following is not used for disinfection of drinking water?
(d) phenyl. (2005)
49. Identify the correctly matched pair:
(a) Basal convention – Biodiversity conservation
(b) Kyoto protocol – Climatic change
(c) Montreal protocol – Global warming
(d) Ramsar convention – Ground water pollution. (2005)
50. Which one of the foliowing pairs is mismatched
(a) fossil fuel burning – release of CO2
(b) nuclear power – radioactive wastes
(c) solar energy – greehouse effect
(d) biomass burning – release of CO,. (2005)
51. In 1984, the Bhopal gas tragedy took place because methyl isocyanaje
(a) reacted with DDT
(b) reacted with ammonia
(c) reacted with CO2
(d) reacted with water. (2004)
52. Lead concentration in blood is considered alarming if it is
(a) 20 mg/100 ml
(b) 30 mg/100 ml
(d) 10mg/100ml. (2004)
53. Common indicator organism of water pollution is
(a) Lemna pancicostata
(b) Eichhornia crassipes
(c) Escherichia coli
(d) Entamoeba histolytica. (2004)
54. Fluoride pollution mainly affects
d) kidney. (2003)
55. Escherichia coli is used as an indicator organism to determine pollution of water with
(a) heavy metals
(b) faecal matter
(c) industrial effluents
(d) pollen of aquatic plants (2003)
56. Which of the following is absent in polluted water?
(b) water hyacinth
(c) larva of stone fly
(d) blue green algae. (2002)
57. Maximum green house gas released by which of the following country?
(d) Britain. (2002)
58. What is B.O.D.
(a) The amount of O2 utilized by organisms in water
(b) The amount of O2 utilized by micro-organisms for decomposition
(c) The total amount of O2 present in water
(d) All of the above. (2001)
59. What is the intensity of sound in normal conversation?
(a) 10-20 dB
(b) 30-60 dB
(c) 70-90 dB
(d) 120-150 dB. (2001)
60. Which is the result of damage to relative biological effectiveness?
(a) high temperature
(d) low temperature. (2000)
61. The Minamata disease in Japan was caused through the pollution of water by
(b) methyl isocyanate
(d) mercury. (1999)
(a) not a pollutant
(b) an antibiotic
(c) a non-degradable pollutant
(d) a biodegradable pollutant. (1999)
63. Which of the following organism is likely to have more concentration of D.D.T. in its body?
(a) top carnivores
(b) primary producers
(d) carnivores. (1999)
64. Which of the following is pollution related disorder?
(d) leprosis. (1999)
65. In 1984, Bhopal gas tragedy was caused due to leakage of
(a) potassium isocyanate
(b) methyl isocyanate
(c) sodium monoxide
(d) none of these. (1999)
66. Which of the following is a secondary pollutant?
(d) CO2. (1999)
67. The maximum biomagnification would be in which of the following in case of aquatic ecosystem?
(d) birds. (1999)
68. Which of the following is the use of lichens in case of pollution?
(a) they promote pollution
(b) lichens are not related with pollution
(c) they treat the polluted water
(d) they act as bioindicators of pollutions. (1999)
69. The supersonic jets cause pollution by the thinning of
(a) O2 layer
(c) CO2 layer
(d) SO2 layer. (1998)
70. Which one of the following organisms is used as indicator of water quality?
(d) Chlorella. (1998)
71. If there was no C02 in the earth’s atmosphere, the temperature of earth’s surface would be
(a) higher than the present
(b) dependent on the amount of oxygen in the atmosphere
(c) same as present
(d) less than the present. (1998)
72. Carbon monoxide is a pollutant because
(a) reacts with haemoglobin
(b) makes nervous system inactive
(c) it reacts with 02
(d) it inhibits glycolysis. (1998)
73. How carbon monoxide, emitted by automobiles, prevents transport of oxygen in the body tissues?
(a) by forming a stable compound with haemoglobin
(b) by obstructing the reaction of oxygen with haemoglobin
(c) by changing oxygen into carbon dioxide
(d) by destroying the haemoglobin. (1998)
74. The most common indicator organism that represents polluted water is
(b) Entamoeba histolytica
(d) P.typhi. (1997)
75. In coming years, skin related disorders will be more common due to
(a) water pollution
(b) depletion of ozone layer
(c) pollutants in air
(d) use of detergents. (1997)
76. MAB stands for
(a) mammals and biosphere
(b) mammals and biology programme
(c) man and biology programme
(d) man and biosphere programme. (1997)
77. Formation of ozone hole is maximum over
(d) Antarctica. (1997)
78. Phosphate pollution is caused by
(a) sewage and phosphate rock
(b) sewage and agricultural fertilizers
(c) phosphate rock only
(d) agricultural fertilizers only. (1997)
79. The true statement about ‘green-house effect’ is that it is
(a) caused by combination of many gases
(b) caused only by CO2
(c) caused by CO2, CFC, CH4 and NO2 gases
(d) none of these. (1996)
80. Which country has the greatest contribution for the hole formation in ozone layer?
(d) Germany. (1996)
81. The two great industrial tragedies namely, MIC and chemobyl tragedies respectively occurred where and at which time?
(a) Bhopal 1984, Ukrain 1986
(b) Bhopal 1986, Russia 1988
(c) Bhopal 1984, Ukrain 1990
(d) Bhopal 1984, Ukrain 1988. (1996)
82. If we uncover half of the forest, covering of the earth, what crisis will be produced at most and at first?
(a) some species will be extincted
(b) population and ecological imbalance will rise up
(c) energy crisis will occur
(d) rest half forests will maintain this imbalance. (1996)
83. When huge amount of sewage is dumped into a river, itsB.O.D. will
(a) slightly decrease
(b) remain unchanged
(d) decrease. (1995)
84. The Taj Mahal is threatened due to the effect of
(d) sulphur-dioxide. (1995)
85. In Minamata Bay Japan the animals which remained free from minamata disease, are
(d) rabbits. (1995)
86. The toxic effect of carbon monoxide is due to its greater affinity for haemoglobin as compared to oxygen approximately by
(a) 200 times
(b) 1000 times
(c) 2 times
(d) 20 times. (1995)
87. Which of the following isotopes is most dangerous to Homo sapiens?
(d) iodine-131. (1995)
88. A dental disease characterized by mottling of teeth is due to the presence of certain chemical element in drinking water. Which of the following is that element?
(d) chlorine. (1995)
89. Which of the following is the main factor of desertification?
(c) irrigated agriculture
(d) all of these. (1995)
90. Which among the following is likely to have the highest levels of D.D.T. depositions in its body?
d) crab. (1994)
91. Which one of the following gases contributes maximum to the ‘green house effect’ on the earth?
(a) carbon dioxide
(b) chlorofluoro carbon
(d) methane. (1994)
92. Sounds above what level are considered hazardous noise pollution?
(a) above 80 dB
(b) above 30 dB
(c) above 150 dB
(d) above 120 dB. (1994)
93. A disease caused by eating fish contaminated by industrial waste, containing mercury compounds, is called
(b) Hashimoto’s oxidase
(c) Bright’s disease
(d) minimata disease. (1994)
94. Ultraviolet radiations from sunlight causes a reaction that produces
(b) carbon monoxide
(c) sulphur dioxide
(d) ozone. (1993)
95. American water plant that has become a troublesome water weed in India is
(a) Cyperus rotundus
(b) Eichhornia crassipes
(c) Typha latifolia
(d) Trapa bispinosa. (1993)
96. Most hazardous metal pollutant of automobile exhausts is
(d) copper. (1992)
97. Petroleum is a
(a) synthetic product
(b) renewable resource
(c) nonrenewable resource
(d) inconvenient resource. (1992)
98. Minerals and metals are
(a) biodegradable resources
(d) renewable and nonrenewable resources. (1992)
99. Which one is not a pollutant normally?
(b) carbon dioxide
(c) carbon monoxide
(d) sulphur dioxide. (1992, 88)
100. Domestic waste constitutes
(a) nonbiodegradable pollution
(b) biodegradable pollution
(d) air pollution. (1991)
101. Acid rain is due to increase in atmospheric concentration of
(a) ozone and dust
(b) CO2 and CO
(c) SO3 and CO
(d) SO2 and NO2. (1991)
102. Green house effect is warming due to
(a) infra-red rays reaching earth
(b) moisture layer in atmosphere
(c) increase in temperature due to increase in carbon dioxide concentration of atmosphere
(d) ozone layer of atmosphere. (1991,89)
103. Major aerosol pollutant in jet plane emission is
(a) sulphur dioxide
(b) carbon monoxide
(d) fluorocarbon. (1990)
104. Gas released during Bhopal tragedy was
(a) methyl isocyanate
(b) potassium isothiocyanate
(c) sodium isothiocyanate
(d) ethyl isothiocyante. (1990)
105. Deforestation will decrease
(a) soil erosion
(b) land slides
(c) soil fertility
(d) rainfall. (1990)
106.Soil conservation is
(a) conversion of sterile soil into fertile one
(b) aeration of soil
(c) erosion of soil
(d) protection against loss. (1989)
107.Acid rains are produced by
(a) excess N02 and S02rom burning fossil fuels
(b) excess production of NH3 by industry and coal gas
(c) excess release of carbon monoxide by incomplete combustion
(d) excess formation of C02 by combustion and animal respiration. (1989,88)
Acid rain is rainfall and other forms of precipitation with a pH of less than 5. Acid rain is caused by large scale emission of acidic gases into the atmosphere from thermal power plants, industries and automobiles. The common ones are sulphur dioxide, nitrogen oxides (NOX), volatile organic carbons (VOCs) and hydrogen chloride. Sulphur dioxide and nitrogen oxides are changed in the atmosphere into sulphuric acid and nitric acid by combining with oxygen and water, which then fall on earth in the form of acid rain.
Eutrophication is the excessive growth of algae, plants and animals in water bodies due to the nutrient enrichment particularly with nitrogen and phosphate. Nutrients present in sewage, agricultural wastes and fertilisers cause dense growth ofplants and planktonic algae. The excessive growth of planktonic algae that cause colouration of water is called algal bloom, which is toxic to animals and humans. Eutrophic water bodies also support excessive growth of floating plants. Algal blooms and floating plants cut off light form submeiged plants, resulting in their death. There is drastic decrease in oxygen replenishment inside water. Non-availability of oxygen results in the death of aquatic animals such as fish, which further adds to organic loading of water. Decomposition is replaced by putrefraction which is anaerobic, leading to absence of oxygen in water and death of aquatic animals.
The 2012 United Nations Climate Change Conference was the 18th yearly session of the Conference of the Parties (COP) to the United Nations Framework Convention on Climate Change (UNFCCC) and the 8th session of the conference of the parties serving as the meeting of the parties to the Kyoto Protocol. The conference took place from November 26, 2012 to December 8, 2012, at the Qatar National Convention Centre, Doha. The conference reached an agreement to extend the life of the Kyoto protocol, which had been due to expire at the end of 2012, until 2020, and to reify the 2011 Durban Platform, meaning that a successor to the protocol is set to be developed by 2015 and implemented by 2020.
Lichens are very sensitive to SO2 pollution. They are completely destroyed at places where there is SO2 pollution in atmosphere. Therefore, they act as very good indicators of S02 pollution.
5. (c) :
Heavy metals and persistent pesticides (e.g., chlorinated hydrocarbons like DDT) pass into food chain and increase in amount per unit weight of organisms with the rise in trophic level due to their accumulation in fat. The phenomenon is called biomagnification/bioconcentration/biological amplification, e.g., 0.003 parts per billion of DDT in water becomes 0.003 ppm in phytoplankton, 0.04 ppm in zooplankton, 0.5 ppm in clams and small fish, 2.0 ppm in predator fish and 25 ppm in fish eating birds like sea gulls.
7. (b) :
Ultraviolet radiations are of three types – UV-C (100 – 280 nm), UV-B (280 – 320nm) and UV-A (320 – 390nm). Shorter ultraviolet radiations (UV-C) are absorbed by the atmosphere. The longer ones (UV-A), are not much harmful. The intermediate or UV-B are harmful as well as capable of deep penetration. Thinning of ozone layer increases the amount of UV-B radiations reaching the earth. UV-B radiations damage skin cells, cause ageing of skin, skin cancer and eyedamage.
Biochemical oxygen demand or BOD is the oxygen required for microbial decomposition of a unit mass of organic remains. The degree of impurity of water due to organic matter is measured in terms of BOD. A higher BOD of a river indicates that water is highly polluted.
Silent spring is an environmental science book written by Rachel Carson. The book documents the detrimental effects on environment, particularly on birds, of the indiscriminate use of pesticides.
10. (d) :
Lichens are composite organisms showing symbiotic association between algae and fungi. They are very sensitive to pollution and their luxuriant growth indicates pure and natural environment at the given location.
11. (c) :
Ozone layer or shield is present in the stratosphere. It is also called ozonosphere where 90% of atmospheric ozone is present. In stratosphere, ozone is being formed and photodissociated. It dissipates the energy of UV radiations.
Dust separation is carried out by scrubbers. They are of two types, dry and wet. Both can be used to separate particulate matter by passing through dry or wet packing material but more commonly they are employed in removing gaseous pollutants like SO2.
13. (c) :
Kyoto protocol is an international treaty to reduce emission of greenhouse gases which was adopted at the third session of the conference of parties (CoP – 3) to the UNFCCC (United Nations Framework Convention on Climate Change) in 1997, in Kyoto, Japan.
16. (c) :
International conference held in Kyoto, Japan obtained commitments from different countries for reducing overall green house gas emissions at a level 5% below than that in 1990 by 2008-2012. In Doha, Qatar on 8th December 2012, the “Doha amendment to the Kyoto Protocol” was adopted. The second commitment period is from 1st January 2013 to 31st December 2020.
17. (b) :
Carbon dioxide is a green house gas with warming effect of 60%. Green house gases are essential for keeping the earth warm and hospitable. They prevent a substantial part of long wave radiations emitted by earth to escape into space and radiate a part of this energy back to the earth. The phenomenon is called green house flux. Because of green house flux, the mean annual temperature of earth is 15°C. Recently the concentration of green house gases has started rising that is resulting in increasing the mean global temperature. It is called global warming. Deforestation has reduced carbon dioxide assimilation. The excess remains in the air. Excessive use of fossil fuel is adding more CO2 to atmosphere. This causes green house effect.
18. (b) :
Particulate matter consists of soot, flyash, dust, spores, pollen grains etc. Particulate matter is differentiated into settleable (larger than 10 mm and remaining in air for less than one day) and suspended (less than 10 mm and remaining in air for more than one day to several weeks). Particles of 2.5 pm and lesser diameter (PM 2.5) are the most harmful to human health (as per Central Pollution Control Board or CPCB). They pass deep into the lungs causing breathing and respiratory problems, irritation, inflammation and damage to lungs resulting in pre-mature death. It cannot directly enter circulatory system but indirectly through respiratory system.
Higher amounts of DDT disturb calcium metabolism of birds resulting in thinning of egg shells and their premature breaking that kills the embryos. Thus many of the eggs laid by birds did not hatch.
20. (b) :
Ozone present in upper atmosphere forms a distinct layer that is known as ozone layer. Ozone layer is necessary for the survival of life on earth as it blocks harmful UV rays of sun from reaching earth’s surface.
21. (a) :
Biochemical oxygen demand (BOD) is the amount of oxygen taken up by microorganisms that decompose organic waste matter in water. It is therefore used as a measure of the amount of certain types of organic pollutant in water.
Eutrophication is often seen in fresh-water lakes. Eutrophication is the process of nutrient enrichment of water and consequent loss of species diversity.
23. (d) :
Nitrous oxide is commonly known as laughing gas or sweet air. It is a chemical compound with formula N20. It is also a major greenhouse gas and air pollutant along with CO2 with tremendous global warming potential. When compared to CO2, N20 has 310 times the ability to trap heat in the atmosphere. N20 is produced naturally in the soil during the microbial processes of nitrification and dentrification. Carbon dioxide from coal-fired power stations and car exhausts, is the main greenhouse gas.
Bhopal gas tragedy took place in the night of December 2/3, 1984, which was worst chemical disaster in history. People started dying within hours and more than 2000 lives were lost in first few days. Methyl isocyanate gas was main chemical released that day, not any radioactive fall out occur and engulfed Bhopal that night.
The IUCN/World Conservative Union is the only Worldwide Conservative Organisation. It is established in 1948 and based in Gland, Switzerland. The IUCN/World Conservation Union endorses captive breeding and habitat protection to maintain viable populations in the world.
Bad ozone is formed in the lower atmosphere (troposphere) that harms plants and animals. Good ozone is found in the upper part of the atmosphere called the stratosphere, and it acts as a shield absorbing ultraviolet radiation from the sun. UV rays are highly injurious to living organisms since DNA and proteins of living organisms preferentially absorb UV rays, and its high energy breaks the chemical bonds within these molecules.
Exhaustible resources are those natural resources which are likely to be exhausted or diminished as a result of their continuous use. These are further of two types – renewable and non¬renewable. Forest is a renewable exhaustible resource which can be again generated or produced artificially or naturally. Coal, petroelum and minerals are non¬renewable exhaustible natural resources which cannot be again produced or generated.
28. (b) :
Unwanted sound is called noise and it is measured in terms of decibels (dB). Generally sound above 80 dB is noise.
Due to heavy industrialization and transportation (modernization), CO2 concentration is increasing day by day in the atmosphere. CO2 has capacity of absorbing heat radiations and thus increases temperature. This increase in global temperature (global warming) is mainly due to CO2 concentration and is called ‘green house effect’. Besides CO2, other important gases associated with green house effect are CH4 (methane), oxides of nitrogen (NOX), CFCs (chlorofluorocarbons) and O3 (ozone) and these are called ‘green house gases’. Relative contribution of these gases to global warming are: CO2 (50%), CFCs (20%), CH4 (16%), 03 (8%), nitrous oxide (6%).
30. (c) :
When sewage mixes with water body, micro-organisms present in it biodegrade organic matter of sewage using oxygen. This results into a sharp decline in dissolved oxygen which may cause mortality of aquatic creatures. Gradually, however, dissolved oxygen increases in concentration with the completion of biodegradation of sewage matter.
The Montreal protocol was signned in Montreal, Canada, by over 150 countries at a convention in 1987 to cut use of CFCs (chorofluoro-carbons). The aim of the protocol was to protect the ozone layer in the stratosphere by decreasing and eventually eliminating the use of ozone depleting substances like CFCs. It is regarded as one of the most successful international treaties in modem history.
32. (c) :
Refer answer 21.
33. (a) :
To control air pollution Government of India has taken some steps. According to Motor Vehicles Act, 1988 petrol driven vehicles are needed compulsory PUC (Pollution Under Control) certificate for low emission of carbon-monoxide and hydrocarbons
34. (d) :
Refer answer 31.
Biomagnification is caused by non-degradable pollutant like DDT. Heavy metals and persistent pesticides (e.g., organochlorine or chlorinated hydrocarbons like DDT) pass into food chain and increase in amount per unit weight of organisms with the rise in trophic level because they are lipo soluble.
36. (a) :
Chipko movement was initially meant for protecting trees but now is meant for preservation of environment including habitat and wildlife. Chipko movement was bom in March 1973 in Gopeshwar in Chamoli district when trees were not allowed to be cut by village folk by hugging them first near village Mandal, then Rampur Phata and in 1974 near village Reni (led by Gaura Devi). The movement had two leaders, Chandi Prasad Bhatt of Gopeshwar and Sunder Lai Bahuguna of Silyara in Tehri region.
A lake near a village suffered heavy mortality of fishes within few days due to accumulation of biodegradable pollutant like DDT sprayed by an aircraft or by several industrial effluents (such as acid, alkalies, phenol etc) or fertilizers like urea and phosphate etc in the water body. These pollutant either lead to biomagnification or eutrophication of water body. Excess of pesticides cause immediate and mass scale death of aquatic animals. Eutrophication leads to decreased oxygen level in water and hence kills aquatic animals.
38. (c) :
Refer answer 18.
Refer answer 29.
The BOD of the given pollutants in ascending order is PE < S < SE < DE
41. (b) :
SPM is suspended particulate matter which is less than 10 mm remaining in air for more than one day to several weeks. It includes aerosol, dust, mist, smoke, soot etc.
42. (d) :
Eutrophication in the phenomenon of nutrient enrichment of a waterbody that initially supports a dense growth of plants and animals. It is caused by runoff from fertilized fields, suburban lawns, detergent rich sewage. Eutrophication is caused by the increase in an ecosystem of chemical nutrients, typically compounds containing nitrogen and phosphorus. It may occur on land or in water. Although traditionally thought of as enrichment of aquatic systems by addition of fertilizers into lakes, bays or other semi-enclosed waters terrestrial ecosystems are subject to similarly adverse impacts. e.g., cause of algal blooms. Increased content of nitrates in soil frequently leads to undesirable changes in vegetation composition and many plant species are endangered as a result of eutrophication in terrestrial ecosystems, e.g., majority of orchid species in Europe.
43. (b) :
Some plants and animals act as the measure of existing environmental conditions because of their response to these conditions. The organisms are called bioindicators. From the given options, stone flies do not act as bioindicator of water pollution. .
Strength of sewage of degree of water pollution is measured in terms of BOD (Biological oxygen demand) value. BOD may be defined as, ‘number of milligrams of 02 required for decomposition of one litre of waste or water by decomposing micro-organisms (bacteria)’. According to central pollution control board, limit of BOD prescribed is < 30 ppm (mg/d) for 3 days at 27° C.
45. (d) :
Photochemical smog is grey or yellow brown opaque smog having oxidising environment with little smoke. Photochemical smog contains secondary pollutants or photochemical oxidants. It was first reported over Loss Angels in 1940s. Photochemical smog is formed at high temperature over cities and towns due to still air, emission of nitrogen oxides and carbohydrates from automobile exhausts and solar energy. Nitrogen dioxides splits into nitric oxide and nascent oxygen. Nascent oxygen combines with molecular oxygen to form ozone. Ozone reacts with carbohydrates to form aldehydes and ketones. Nitrogen oxides, oxygen and ketones combine to form peroxy-acyl- nitrates (PAN). In areas with intense solar radiations, photoelectrical smog forms brown air.
Refer answer 31.
47. (c) :
Irrigation induced salinity can arise as a result of the use of any irrigation water, irrigation of saline water etc. combined with inadequate leaching. Since all surface and ground water contains salts to varying degrees, irrigation is often seen as the primary culprit for bringing salts into the field.
48. (d) :
In a sewage efficient treatment plan (CETP) during the tertiary treatment the decreased water is chlorinated with chlorine or perchlorate salts, ozonised or irradiate with UV to kill pathogens. Phenyl is not used for disinfection of drinking water.
Refer answer 13.
Due to heavy industrilization and transportation (modernization), CO2 concentration is increasing day by day in the atmosphere. CO2 has capacity for absorbing heat radiations and thus increases temperature. This increase in global temperature (global warming) is mainly due to CO2 concentration is called green house effect. Complete combustion of fossil fuels and biomass releases carbondioxide. Nuclear power plants releases radioactive wastes.
51. (d) :
Bhopal gas tragedy occurred on 3 Dec. 1984 in a Union Carbide pesticide plant. When water and MIC mixed, an exothermic chemical reaction started, which produced a lot of heat. As a result, the safety valve of the tank burst because of the increase in pressure. This burst was so violent that even the concrete around the tank also broke. The high moisture content (aerosol) in the discharge while evaporating gave rise to a heavy gas which rapidly sank to the ground. It caused several of the following ailments like partial or complete blindness, disorders like, gastrointestinal disorders in many surviving people.
52. (b) :
Lead (Pb) is released by combustion of petrol as tetra ethyl lead is used as antiknock in petrol. This lead is very harmful and causes plumbism or lead poisoning, which disturbs nervous system, liver, kidneys in adults and also causes brain damage in children. About 150 to 400 mg of lead is stored in the body of an average adult and blood levels average about 25 mg/100 ml. Increase to 70 mg/100 ml of blood is generally associated with clinical symptoms. Hence a level of 30 mg/100 ml should be considered alarming.
53. (c) :
E.coli is the most common indicator of water pollution. It naturally occurs in the intestines of human beings and animals. They are commonly found in sewage and if E.coli are detected in water then it indicates fecal contamination. So if E.coli are detected in drinking water it indicates a serious he<h risk and that water should not be used for drinking.
54. (c) :
Fluorides are given out during refining of materials. Fluorides cause flourosis. It is a disease which is defined by mottling of teeth, abnormal bones that are liable to fracture because flourine replaces Ca2+ and makes the bones brittle. Fluoride pollution is a serious problem in many districts of Rajasthan, where excess of fluoride in water adversely affects the health of man. Many villagers have aged prematurely or became hunch backs.
55. (b) :
Refer answer 53.
Stone fly (plecoptera order) larva requires well aerated, non-polluted water. It is absent in polluted water.
58. (b) :
Refer answer 44.
59. (b) :
Unit of sound level is decibel. As referrence intensity, sound ofnoise level is taken as 0 0 dB. 10 dB is ten times the threshold intensity, 20 dB 100 times, 40 dB is 104 , 100 dB is 1010 times the threshold intensity. Moderate conversation produces 60 dB sound. Unwanted sound is noise and is therefore pollutant.
Pollution is any change in physical, chemical or biological charecteristics of the environment that has the potentiality to harm human life, life of other desirable species, natural resources, cultural assests and industries. Another type of pollution is increase in CO2 and other greenhouse gases and a decrease in stratospheric ozone on global scale which would be affecting air, water and land resources, biological diversity and human health. Thus pollution results in damage to biological effectiveness.
61. (d) :
Mercury is changed to water soluble dimethyl mercury which undergoes biomagnification. Eating poisoned animals causes deformity known as Minamata disease (first reported in 1952 due to eating of fish captured from Hg-contaminated Minimata Bay of Japan) which is characterised by diarrhoea, hemolysis, impairment of various senses, numbness oflips, tounge, limbs, deafness, blurring of vision, mental dearrangement, meningitis and death.
DDT (dichloro diphenyl trichloroethane) is a non- biodegradable pesticide. It is persistent, fat soluble and shows biomagnification. So they are more harmful to higher tropic level organisms.
Refer answer 35.
Refer answer 54.
Refer answer 51.
66. (a) :
Secondary pollutant is formed from a primary one through change or reaction. The secondary pollutant are more toxic than primary ones. Nitrogen oxides and hydrocarbons react photochemically to produce peroxyacyl
nitrates and ozone. Peroxyacyl nitrates are produced due to photochemical reactions between nitrogen oxides and unsaturated hydrocarbons.
Nitrogen oxides + Hydrocarbons →UVin sunlight ( Peroxyacetyl nitrate (PAN) and Ozone ( O3)
67. (c) :
Pesticides sprayed over crops also pass into water bodies due to surface run-off. In excess they cause immediate and mass scale deaths of aquatic animals. Persistant pesticides (e.g. organochlorine or chlorinated hydrocarbons like DDT) pass into food chain and increase in amount per unit weight of organisms with the rise in trophic level due to their accumulation in fat. The phenomenon is called biomagnification, e.g. 0.01-0.05 parts per billion in water, 25 parts per billion or 0.025 ppm in phytoplankton, 0.123 ppm in zooplankton, 1.04 ppm in clams and small fish, 4.83 ppm in predator fish and 124 ppm in fish eating birds like Sea Gulls. So the maximum biomagnification occurs in fishes in case of aquatic ecosystem.
68. (d) :
Lichens are bioindicators of air pollution. The algal symbiont of lichen is most vulnerable to S02 pollution. The following chemical reactions take place during chlorophyll degradation of the phycobiont under the influence of S02.
so2 + H2O H2SO32-
H2SO32- HSO3– + H+.
Chlorophyll a + 2H+ —> Phaeophytin – a + Mg2+.
So in a S02 polluted area, lichens will die first.
Depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone. Ozone depleting substances react with ozone present in the stratosphere and destroy the same. The major ODS are chloroflourocabons (14% of total depletion), nitrogen oxides (3.5% depletion sulphur dioxide, halon, carbon tetrachloride, methyl •chloroform, chlorine, etc. Many of these are being released by jets flying in the stratosphere and rockets being fired into space.
Refer answer 53.
71. (d) :
Carbon dioxide is one of the important green house gas. It allows the shorter wavelength of infra red radiations to pass through it but does not allow these radiations to leave the earths atmosphere. This results
in warming of the atmosphere. If the amount of CO2 decreases then there will not be any increase in temperature.
72. (a) :
Carbon monoxide but are gaseous cycle is produced due to incomplete combustion, metallurgical operations and naturally by plants as well as animals. Carbon monoxide has 200 times more affinity within haemoglobin as compared to oxygen. Cabon monoxide combines with haemoglobin of blood and forms a stable compound called carboxyhaemoglobin. At 50 ppm, CO converts 7.5% of haemoglobin into carboxy ¬ haemoglobin within 8 hours. It impairs oxygen transport resulting in headache, decreased vision, cardiovascular malfunction and asphyxial.
Refer answer 72.
74. (c) :
Refer answer 53.
75. (b) :
Ozone layer or shield is present in stratosphere. It functions as a shield against strong UV radiations. Protection from UV radiations is proportional to thickness of ozone layer. Depletion in the concentration of ozone over a restricted area as spring time decline over Antartica is called ozone hole. Thinning of ozone layer increases the amount of UV-B radiations reaching the earth. It would increase occurence of cataract, skin cancers, herpes, dimming of eye sight, photobuming, deficient functioning of immune system.
76. (d) :
Man and biosphere programme is an international biological programme of UNESCO (United Nations Educational Scientific and Cultural Organisation) which was started in 1971 but was introduced in India in 1986. MAB has studied human environment, impact of human interference and pollution on biotic and abioticenvironments and conservation strategies for the present as well as future.
77. (d) :
Depletion in the concentration of ozone over a restricted area as spring time decline over Antartica is called ozone hole. An ozone hole was discovered over Antartica by Faman et al, 1985. It is quite large (23 million square km in 1992 and 28.3 million square km in 2000). A small ozone hole also occurs over North Pole. It was discovered in 1990. Thinning of ozone shield has also been reported elsewhere(e.g., 8% between 30°-50°N).
78. (b) :
Phosphate is an important compound of fertilizer which are added to crop fields and then are passed down to water bodies during rains through ran off. It is also present in sewage that is dumped into the water body. This nutrient bring about dense growth of water plants especially the algae and cause algal bloom. This algal bloom leads to oxygen depletion in water bodies and causes death of aquatic life.
79. (c) :
Refer answer 29.
80. (c) :
Depletion in the concentration of ozone over a restricted area as spring time decline over Antartica is called ozone hole. Depletion of ozone is due to action of sunlight over pollutants which release chemicals (e.g., chlorine) that destroy ozone. The major are chloroflouroarbons (14% of total depletion), nitrogen oxides (3.5% deplection sulphur dioxide, halon, carbon tetrachloride, methyl chloroform, chlorine, etc. Major contributor of these gases is USA.
82. (a) :
Deforestation will affect in different ways. Due to destruction of natual habitat, many species will get extinct. Man will be deprived of the benefits of trees and wild animals. Soil erosion will be increased. Floods and drought will become more frequent. There will also be a change in climate. Deforestation will also decrease the atmospheric humidity which will affect rainfall and makes the air hot. Economy of the forest dwelling people will be deteriorated and wild life will be adversely affected.
83. (c) :
Refer answer 30.
The Taj Mahal is built with white marble and is threatened by environmental pollution, especially due to sulphur dioxide. Sulphur dioxide is produced during combustion of fossil fuels, refining of petroleum and smelting of sulphur containing ores. Threat to Taj Mahal from Mathura refinary is due to pollutant gases composing SO2, H2S and nitrogen oxides. They would convert CaCO3 (marble) into calcium sulphate and calcium nitrate.
85. (d) :
Refer answer 61.
86. (a) :
Refer answer 72.
87. (b) :
Strontium-90 is a long lived radionuclide. It tends to cycle like calcium.lt causes bone cancer, blood and tissue degeneration.
88. (a) :
Refer answer 54.
89. (a) :
Desertification means a process of spread of desert that occurs due to degradation of environment, cutting of trees, soil erosion etc. It can be natural or man made. The main causes for desertification are overcultivation of poor soils, over grazing by animals, excessive cutting of fuelwood and inappropriate irrigation practises resulting in salinization. Among them overgrazing is the most important factor as it causes maximum effect.
90. (a) :
Refer answer 67.
91. (a) :
Refer answer 29.
92. (d) :
Noise level are expressed on a logarithmic scale A decibels. The baseline noise levels in the community vary around 40 dB. International standards prescribe a maximum of 50 dB for day and 40 dB for night time in a desidential area. Noise over 115 dB is regarded as highly voidable. The World Health Organization (WHO) recommends an industrial noise limit of 75 dB.
Refer answer 61.
94. (d) :
Ozone is generated in the lower atmosphere during the formation of photochemical smog when nitrogen dioxide splits to produce reactive oxygen atoms which combine with molecular oxygen. Oxygen molecules split under ultraviolet radiations to produce oxygen atoms which combine with molecular oxygen to form ozone. It is this gas which forms the protective ozone umbrella in the stratosphere and shield life from biocidal high energy radiations. It can also damage DNA molecules and cause carcinogenesis.
95. (b) :
Eichhornia crassipes or water hyacinth (American water plant) has become the most serious weed in many tropical, warm and temperate freshwater habitats worldwide including India. It has the highest growth rate of any saltwater, freshwater or terrestrial vascular macrophyte and can be labelled as an “ecosystem engineer” or an invasive habitat modifier. In slow-moving to still water bodies it is especially problematic as it forms dense monospecific mats that lower dissolved oxygen levels in the water, alter river hydrology and increase organic sediment. These mats displace native aquatic plant and animal communities, drastically alter the ecosystem and puts native habitats and wildlife at risk. Furthermore, water hyacinth may interfere with the use of a water-body for cultural, social or commercial purposes causing substantial economic hardship and putting livelihoods at risk.
Lead is the most hazardous metal pollutants of automobile exhausts. Its effects are lead poisoning, anaemia, kidney disease and convulsions. It also affects central nervous system and distorts the red blood corpuscles.
98. (d) :
Metals and minerals are both renewable and non-renewable resources. Non renewable due to very long recycling in case of metals and some minerals but renewable due to shorter recycling in case of biogenetic nutrients.
99. (b) :
The common gaseous pollutants are oxides of carbon (CO and CO2), oxides of nitrogen (NO and NO2) oxides of sulphur (SO2 and SO3), all these together contribute 90% of the global air pollution. Out of all these CO2 is not a pollutant normally, the green plants, by photosynthesis balance the CO2 and O2 ratio in the air to a great extent, whereas others like carbon monoxide, NO2 etc are poisonous gases.
100. (b) :
Domestic waste constitutes biodegradable pollution. These are also called non-conservative pollutants. These are decomposed chemically or by activity of microorganisms into harmless products and are recycled back into the atmosphere.
101. (d) :
S02 and N02 when present in large quantities dissolved in water vapour form sulphuric acid and nitric acid which dissolve in rain water resulting in acid rain (H2SO4) and (HNO3) which intum causes great damage to forests and vegetation.
102. (c) :
The mean global temperature rise by 2° – 6°c and the concentration of carbon dioxide increases in the troposphere upto 600 ppm. Hence, the surface of the earth becomes warm which causes global warming. The phenomenon is similar to that of green house in which the glass enclosed atmosphere gets heated up due to its insulation from the rest of the environment. Hence, global warming is also known as green house effect and the gases responsible for it are called green house gases e.g CH4, CO2 etc.
103. (d) :
Aerosols are chlorofluoro-hydrocarbon compounds released into air with force in the form of vapour. Main source of aerosols is the emission of jet planes, where fluorocarbon are used. These chlorofloro- carbons depletes the ozone layer in the higher atmosphere. These CFC’s have produced a hole in the ozone layer.
104. (a) :
Refer answer 51.
105. (d) :
Deforestation is the conversion of forested areas to non-forest land use such as arable land,
pasture, urban use, logged area, or wasteland. Generally, the removal or destruction of significant areas of forest cover has resulted in a degraded environment with reduced biodiversity. Deforestation results from removal of trees without sufficient reforestation, and results in declines in habitat and biodiversity, wood for fuel and industrial use, and quality of life. Due to deforestation, transpiration will be decreased, air temperature will be increased and water content will be decreased hence rainfall decreases.
106. (d) :
Soil conservation is to conserve fertile soil
from the losses like heavy rainfall, drainage, high wind, flood, draught etc. Soil is the top cover of the earth in which plants can grow. The rotation of crops, contour ploughing and use of proper fertilizers help in maintaining the fertility of soil. Plantation of trees, controlled grazing of grasslands, reforestation, prevention of forests fires will protect the erosion of top soil. The regulation of water resources to prevent flood will help not only in soil conservation but also supply an adequate water supply in the period of drought.
107. (a) :
Acid rain refers to the preceipitation with a pH of less than 5. It is a mixture of H2SO4 and HNO3, the ratio of the two acids vary depending on the relative quantities of sulphur oxides and nitrogen oxides present in the atmosphere. These oxides are mainly produced by combustion of fossil fuels, smelters, industries, power plants, automobile exhausts etc.