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Karnataka 2nd PUC Biology Question Bank Chapter 16 Environmental Issues

2nd PUC Biology Environmental Issues NCERT Text Book Questions and Answers

Question 1.
What are the various constituents of domestic sewage? Discuss the effects of sewage discharge on a river.
Domestic waste – Waste that is produced from our homes and passed down into sewer system matter that floats . Effects of sewage on river.

Quality of water is decreased . So it becomes unsuitable for bathing, domestic uses etc.,
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 1

B.O.D- [Biological oxygen demand] – More waste in water, more decomposers come into action, much larger amount of O2 utilized so, B.O.D. increases and dissolved oxygen becomes less.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 2

KSEEB Solutions

Question 2.
List all the wastes that you generate, at home, school or during your trips to other places, which you could easily reduce? Which would be difficult or rather impossible to reduce?

  • At home – Kitchen wastes, food-left overs, old torn clothes, papers, carry bags, cotton, broken articles (glass, crockery), leather, plastic, cans etc.,
  • At school – Pencil, pencil peels, rubbers, pens, chalk, paper, food, grit etc.,
  • At trips – Food, carry bags, food wrappers, water bottles, cups, spoons, plate, faeces and urination in open air.
  • Wastes which can be reduced – Biodegradable wastes e.g. papers, rags, food, leather articles, others which are recyclable ones in house or locality itself.
  • Which cannot be reduced – Glass, tin, metals, plastics, polythene. They are recycled and reused. Also as land fills. So non biodegradable are to be sold to ragpickers.

Question 3.
Discuss the causes and effects of global warming. What measures need to be taken to control global warming?

  • Global warming is rise in mean temperature of lower atmosphere and earth’s surface.Causes – increase in quantity of radioactively active green house gases CO2, CH4, N2O, CFCs. They allow heat waves to reach surface and prevents their escape.
  • They are produced by combustion of fossil fuels, biomass [CO2]; burning of nitrogen rich fuels [N2O]; paddy fields, fermentation in cattle and wet lands [CH4]; refrigerators, aerosols, drying, cleaning [CFCs].
  • Effects: Heating of earth surface [mean temperature is increased] Climatic changes e.g.: El Nino effect.
  • Increased melting of polar ice caps and Himalayan snow caps. Increased sea levels and coastal areas will submerge.
  • Measures – Decreased use of fossil fuels, improve efficiency of energy usage, Reduce deforestation, plant trees Control of man made sources of green house gases like vehicles, aerosol sprays.

Question 4.
Match the items given in column A and B:

Column A Column B
(a) Catalytic converter – (i) Particulate matter
(b) Electrostatic – (ii) Carbon precipitator monoxide and nitrogen oxides
(c) Earmuffs – (iii) High noise level
(d) Landfills – (iv) Solid wastes
(a) Catalytic converter – (i) Co & NO
(b) Electrostatic – precipitator (ii) Particulate matter
(c) Earmuffs – (iii) High noise level
(d) Landfills – (iv) Solid wastes

Question 5.
Write critical notes on the following:
(a) Eutrophication
(b) Biological magnification
(c) Groundwater depletion and ways for its replenishment.
(a) Eutrophication :-
Natural aging process of lakes by nutrient enrichment of its water. In young lake water is cold and clear and supports only little life. With time, streams introduce nutrients into lake which increases lakes fertility and encourages aquatic growth. Over centuries silts and organic debris pile up, and lake becomes shallow and warmer. It supports plants and later gets converted into land. Lakes span depends on climate, size of lake.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 3
(b) Biological magnification: Bio magnification is due to introduction of toxic substances from industrial and household waste into aquatic food chain. Concentration of toxic substance accumulated by organism increases at each trophic level – Bio magnification, eg: Toxic substances like mercury, DDT, etc.
They later lead to entrophication.

Birds (25 ppm)

large fish (2ppm)

small fish (0.5 ppm)

zooplankton (0.04 ppm)

water (0.003 ppm)
(DDT concentration showing bio magnificarion)

(c) Groundwater depletion and ways for its replenishment
Groundwater depletion – due to high demand of water in urban, hilly, arid areas where surface water is not available or polluted, ground water is the major source of water drawn using tube wells, pumps etc., [in Punjab, T.N, Rajasthan]

Replenishment –

  • Reduced consumption or stop using groundwater for irrigation and cleaning etc.
  • Rainwater harvesting – Collection of rainwater and diverting them into ground using pipes or into rivers or rainwater tanks. [As alternate source of water also].

Question 6.
Why ozone hole forms over Antarctica? How will enhanced ultraviolet radiation affect us?
Ozone hole forms over Antarctica where no one lives and no pollution is present but not over Newyork, Bangalore etc., (polluted cities). It is because CFCs and ozone depleting substances (ODS) released world wide accumulates in stratosphere and drifts towards, Antartica in winters (July – August) when temperatures is -’85° C in Antartica.

In winters polar ice clouds are formed over Antartica. It provides catalytic surface for (CFCs and other ODS to release CL and other free radicals that breakdown ozone layer forming ozone hole during spring in presence of sunlight. In summer, ozone hole disappears due to mixing of air world wide.

Ozone holes allows UV radiations (UVA & UVB) to reach earth surface. Which was earlier reflected by ozone layer. UVB damages DNA, skin cells and causes mutations and skin cancer’s respectively. UVB even causes corneal damage (Snow Blindness).

KSEEB Solutions

Question 7.
Discuss the role of women and Communities in protection and conservation of forests.
(i) Bishnois – are group of followers of Guru Janbeshwar Maharaj, a small community inhabiting a village near Jodhpur in Rajasthan. They are known for peaceful co-existence with nature. In 1731, once when king of Jodhpur, asked his fellow people to arrange wood for new palace, they reached Bishnois village. Effort of cutting trees was thwarted by Bishnois. A Bishnois women Amrita Devi hugged the trees and daring King’s men to cut her before cutting the trees. But, kings men cut the tree down along with her. Her 3 daughters and 100 other Bishnois followed her and all lost their lives saving trees. Now there is Amrita Devi Bishnoi Wildlife Protection Award given to individuals or communities from rural area who show courage and dedication to protect wildlife and trees.

(ii) Chipko movement – of Garhwal Himalayas. In 1974, local women showed extreme courage by hugging trees and protecting them from the axe of contractors.

(iii) Appiko movement – Conservation, plantation and Rational use is their belief.
(iv) Joint Forest Management (JFM) – Government of India in 1980s introduced concept of JFM so as to work closely with local communities for protecting and managing forests. In return their service, they were rewarded with various benefits and forest were conserved in. sustainable manner. Communities got benefit of various forest products like fruits, gum, rubber, medicine etc.

Question 8.
What measures, as an individual, you would take to reduce environmental pollution?

  • No biomass burning and minimal use of fossil fuels.
  • Vehicles – use of minimum pollution vehicles fitted with catalytic converters.
  • Smoking – No tobacco smoking and implementation of Kitchen chimneys
  • Noise – Not using TV and other gadgets at louder pitch.
  • Tree plantation -1 will plant trees around school, house and also in other places.
  • Wastes -1 will dispose of waste property after segregation.

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Question 9.
Discuss briefly the following:
(a) Radioactive wastes
(b) Defunct ships and e-wastes
(c) Municipal solid wastes
Radioactive wastes – Nuclear energy
(source of non-polluting electricity) has 2 important problems

  • Accidental leakage (Chernobyl incident);
  • safe disposal is a problem for radioactive waste.

Radiations are extremely damaging to organisms, because of its mutations at very high rate. At high doses, it is lethal but at lower doses, creates various disorders like cancer, anomaly, etc. Their disposal is also a serious issue. Low level and intermediate level wastes do not produce – heat and other environment problems, so are safe dumping in process inside proper containers. But high level wastes which release lots of heat and cause environmental problems are put in suitable containers and buried 500 m deep inside rocks inside the earth.

(b) Defunct ships and e-wastes. Defunct ships – old ships are dismantled to obtain scrap and other useful materials mainly in developing countries , due to less labour charge and low tax. Workers engage in ship breaking are exposed to number of toxicants like asbestos, lead, mercury etc. Coastal area associated with ship breaking yard in also polluted.

e-wastes (electronic wastes) – They are increasing due to increase use of e – equipments and rapidly changing technologies. From it metals (copper, iron, silicon, nickel, gold) etc. are extracted. Dismantling also exposes them to toxic substances.

(c) Municipal solid wastes – Domestic waste office wastes, school, public sweeping, sludge from sewage treatment plants, vegetables, fruit markets. They may be bio-degradable or non¬bio-degradable. They consists of paper (40%), food waste (7%), glass, crockery, rubber,- leather, plastics etc. Their disposal is mainly done by: Pig and cattle feeding, salvage, Burning, incineration, land fills, pyrolysis (heat), composting, Biogas plants, Recycling etc.

KSEEB Solutions

Question 10.
What initiatives were Jtaken for reducing vehicular air pollution in Delhi? Has air quality improved in Delhi?
Initiatives taken were:
A PIL (Public Interest Litigation) was filed before supreme court of India. Supreme court undertook time bound measures for reducing pollution by switching over to CNG is public transport, enforcement of Eura II norms, periodic pollution checkup, use of unleaded petrol, catalytic converters in vehicles and phasing out old vehicles. Air quality has improved significantly. A substantial fall in CO2 and SO2 has been found in Delhi between 1997 and 2005.

Question 11.
Discuss briefly the following :
(a) Greenhouse gases
(b) Catalytic converter
(c) Ultraviolet B
Green house gases – are those gases which allow short wave radiations to pass through but absorb long wave heat radiations: eg: CO2, CH2, N2O, CFCs.
They cause green house effect and increases surface temperature making earth. Sustainable or life

Question Downward flux of long waves by green house gases is called green house reflux. It keep earth warm at 15°C, without it earths temperature would dropto-18°C.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 4
But enhanced green house effect causes globalwarning that is leading to deleterious changes in environment and resulting in odd climate changes.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 5
(b) Catalytic Converter : It is a method to reduce emissions from automobiles. The device has a platinum – palladium and Rhodium as catalyst. Exhaust emissions passes through it; nitric oxide splits into nitrogen and oxygen, Carbon monoxide into carbon dioxide, unburned hydrocarbons get burned to form CO2 and H2O. It is useful only is unleaded petrol because lead inactivates catalyst of the convertor.

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(c) Ultraviolet B (UVB) – They normally do not reach earth surface as ozone layer reflects it back. But due to ozone hole, UVB reaches earth surface these days.
They cause:

  • Skin cancer
  • Blinding – Corneal damage .
  • Immune system is partially suppressed
  • Larval stages die
  • Photosynthesis – is impaired so crop yield falls.
  • Nucleic acids – Mutations
  • Phytoplankton – their function is disturbed so productivity falls.
  • Global warning.

2nd PUC Biology Environmental Issues Additional Questions and Answers

2nd PUC Biology Environmental Issues One Mark Questions

Question 1.
Name any 3 gases contributing to green house effect. (CBSE 2004)
CO2, methane (CH4), Nitrous oxide (N2O).

Question 2.
Which type of UV-radiations can be lethal to organisms. (CBSE 2005)
The most harmful UV-radiation is UV- C have a range of 100-280 nm. They are absorbed by oxygen molecules of atmosphere. The next goes to UV-B with a range of 280-32 nm wavelength.

Question 3.
What are ODS. Give examples. (CBSE 2005)
Certain substances react with ozone present in the stratosphere and destroy the ozone. They are called ozone depleting substances or ODS. The majors ODS are CFCs, halons (gases used in fire extinguisher i. e. like bromo chloride fluoro methane), N2O, CH4, Cl etc.

Question 4.
What is ozone shield or ozone layer?
The region in stratosphere where ozone is present in high concentration is called ozonosphere or ozone layer or ozone shield.

Question 5.
What is ozone hole?
The thinning of ozonal layer over the Antarctic region is called ozone hole.

Question 6.
What is acid rain.
It is the deposition of acidic chemicals of atmosphere over the earth by combining with rain droplets.

Question 7.
What constitute smog.
It is opaque dark fog which is formed by smoke, dust, oxides of sulphur, nitrogen, H2S, water vapour etc.

Question 8.
Expand the term PAN and BOD, PPN. (CBSE 2005, 2007, 2008)

  • PAN – Peroxy acyl nitrate
  • BOD – Biological oxygen demand
  • PPN – Peroxy – propional nitrate.

Question 9.
Many villagers near Industrial are a sufferer from “blue baby syndrome! How is this problem caused. (CBSE 2004)
From the industries, nitrate containing impurities add to the water causes water pollution. When these people drink this water, nitrite changes into nitrate and passes into blood and oxidises ferrous of haemoglobin to ferric ion. This way formed hemoglobin is called methemoglobin. This reduces, oxygen carrying capacity of blood. This results in cyanosis in infants called blue baby syndrome.

KSEEB Solutions

Question 10.
What is Sonic Boom?
It is a series of shock waves left behind by a supersonic Jet flying at a speed. It produced sudden rattling of windows and doors. Building many develop cracks.

Question 11.
Define biomagnification.
It is the increase in the concentration of certain toxic chemicals like DDT at successive trophic levels through food chain is called biomagnfication.

Question 12.
What do you mean by entrophication?
It is defined as the nutrient enrichment in the water bodies leading to the depletion of oxygen and deadening of the life supporting environment, due to slow ageing of water bodies.

Question 13.
What is meant by algal bloom?
The excessive growth of certain phyto planktons, facilitated by the excess presence of nutrients in the water bodies is called algal bloom.

Question 14.
Name the world’s most problematic aquatic weed? What is the nature of water body in which this weed grow? (CBSE 2008)
Eichhomia crassipes is the problematic aquatic weed grow in eutrophied water body.

Question 15.
Expand CPCB..
Central Pollution Control Board.

Question 16.
Define Pollutants.
Those agents which bring undesirable change in the physical chemical and biological characteristics of air, water and soil are called pollutants.

Question 17.
Write the main aim of Environment Act in 1986 (pollution).
“Protect and improve the quality of our environment i.e. air, water and soil”.

Question 18.
What is meant by green house effect?
Green house effect is a naturally occurring phenomenon, in which the short wave radiations of solar energy are absorbed and long wave radiations are reflected by the earth, but reabsorbed by certain gases and increases the, temperature of earth’s surface and atmosphere.

Question 19.
Between amphibians and birds, which will be able to cope with global warming? Give reason.
Birds. Because they are warm blooded animal can adjust the body temperatures as per the changes in the environment.

Question 20.
What gases cause stratospheric ozone depletion? What is the result of this depletion? (CBSE 2004)
N2O, CH4, CO2, chlorine are some of the gases lead to the ozone depletion. The depletion leads to the ozone hole which allows the entry of UV-B radiation to the earth surface. This radiation causes skin cancer, blindness, global warming etc.

Question 21.
What will be the consequences if the electrostatic precipitator of a thermal power plant fails to function?
In the absence of electrostatic precipitator the particulate pollulants and gaseous pollutants of the exhaust will get into the atmosphere.

Question 22.
What is Snow blindness.
Snow blindness is the inflammation of cornea caused by a high dose of UV-B radiations.

Question 23.
Where did the Chipko movement start?
In Garhwal Himalayas.

Question 24.
What is Chipko movement?
The movement led by Gaura Devi along with Sunder Lai Bahuguna of Tehri region of Uttara Khand to prevent felling of trees by hugging the trees.

KSEEB Solutions

Question 25.
What JFM. What is its main objectives.

  • Joint Forest Management.
  • Protection of Sal forest by local communities.

Question 26.
What ITS the main objective of Montreal Protocol?
Limiting production and consumption of chlorofluro carbon to half the level.

2nd PUC Biology Environmental Issues Two Marks Questions

Question 1.
What are major causes of soil erosion?

  • Over Cultivation
  • Poor irrigation practices
  • Deforestation
  • Unrestricted grazing.

Question 2.
What is Montreal Protocol? What is its aim?
Montreal Protocol is an international treaty, that was signed at Montreal (Canada) in 1987 and become effective in 1989. The main .aim is to control the emission of a ozone depleting substances.

Question 3.
Waterlogging can increase the soil salinity. Discuss.
Waterlogging draws salt to the surface of the soil. This salt is then deposited as a thin crust on the land surface and starts collecting roots of the plant.

Question 4.
Mention the harms caused by fine particulates in human.

  • They may be inhaled deep into the – lungs and cause breathing and respiratory problems.
  • Irritation of lungs.
  • Inflammation of lungs.
  • Premature death.

Question 5.
How is letting of sewage into water bodies cause fish mortality?

  • As the sewage is discharged into water bodies, there is an increase in the biodegradable organic matter.
  • The micro organisms multiply fast with the increase in organic matter, which Is used as its substrate for them.
  • These microbes consume a lot of oxygen and there is a sharp decline in the dissolved oxygen content of the water body, this leads to fish mortality.

Question 6.
Differentiate between Biodegradable and non biodegradable waste.

  • Biodegradable: These are the waste which can be broken down into simpler harmless substances by the activity of decomposers. These substance are used as manures.
  • Non-biodegradable: The substances which cannot be broken down into simpler substances by microbes and they start accumulating in the biosphere.
    This causes pollution and can lead to biomagnification.

Question 7.
Write an account on Ecosan -Ecological sanitation.

  • Ecological sanitation is a subtainable system for handling human excreta, using dry composition toilets.
  • This is a practical, hygienic, efficient and cost effective solution to human waste disposal.
  • In this method, human excreta an be recycled into manures that reduce the need for chemical fertilizers.
  • There are working ecosans in Kerala and Srilanka.

Question 8.
How is organic farming advantageous?

  • This allows maximum utilization of resources.
  • It increases the efficiency of production.
  • There is no need for chemical fertilizers for crops, as cattle excreta, can be used as manures.
  • Crop wastes are also decomposed and used as manures.
  • Cattle dung and crop wastes are used to generate biogas, that is used for cooking and lighting.

Question 9.
How is the green house effect caused?

  • The atmospheric gases absorb half of the incoming solar radiations and heat the earth surface.
  • Earth surface re-emits the heat in the form of infra red radiation.
    A large part of this is absorbed by the green house gases (CO2, CH4, N2O, CFCs etc).
  • The molecule of these gases radiate heat energy back into the atmosphere and the earth’s surface is heated up once again.
  • This cycle is repeated a number of times and there is an increase in the global temperature.

KSEEB Solutions

Question 10.
Differentiate between “Good ozone” and “Bad ozone”.

Good ozone Good ozone
Good ozone refers to the ozone found in the stratosphers. Bad ozone refers to the ozone found in the troposphere.
It absorbs UV radiations and protects the living organisms of the earth. This is harmful to plants and animals.

Question 11.
Mention any 3 reasons for deforestation.
Deforestation is caused due to human activation for following purposes.

  • Forests are cleared for making homes and industries due to over population.
  • Forests are converted into agricultural land to produce food for increasing population.
  • Trees are fell for timber, firewood and other uses.

Question 12.
Thermal power plants are necessary to any country, but they cause harm to the environment and community. Mention how they are harmful to the environments and people. What precaution can be taken to avoid this effect?

  • Thermal power plants release both particulate and gaseous air pollutants from their smoke stakes.
  • When they are inhaled, it cause breathing respiratory disorders, irritation and inflammation of lungs leading to premature death.
  • By installing an electrostatic precipitator, more than 99% of the particulate matter will be absorbed.
  • Scrubbers can be used to remove gaseous pollutants.

Question 13.
“Eutrophication can lead to the death of a lake” Discuss.

  • The main pollutants in sewage, industrial wastes and agricultural run off are nitrates and phosphorus.
  • These pollutants stimulates the growth of algae which leads to the depletion of oxygen in water bodies, causes the death of aquatic organisms.
  • Other toxic substances flowing into the lake can kill all the fishes and other animals in the water.
  • Due to the decomposition of these bodies the oxygen level further decreases in the water body
  • Ultimately this leads to the death of the lake.

Question 14.
What does BOD indicate? What is its relationship with the dissolved oxygen content of the water body?
BOD is Bio logical oxygen demand which is measure of the oxygen required by aerobic decomposers for the degradation of biodegradable organic matters in the water bodies.
If BOD is higher, it indicates the high level of organic matter and viceversa.

2nd PUC Biology Environmental Issues Three Marks Questions

Question 1.
Mention the harmful effects of noise on human health.

  • Sleeplessness and headache
  • Noise level of 150 dB or more than these can cause permanent hearing impairment
  • Increased heart beating and blood pressure
  • Difficultly in breathing
  • Strees and strain

Question 2.
Describe the particular type of agriculture practised in north eastern states of India which has also contributed to deforestation. What is it commonly called as?
Slash and Burn agriculture is practised in north-eastern states of India.
In this method the farmers cut down the trees of the forest and burn them and clear a certain area for farming.

The ash is used as manure and the land is used for cultivation of crops or grasses for cattle grazing. ‘After cultivation for a period of time, the land is left free for several years to allow its recovery The farmers move to a different areas in the forest and this process is repeated. This practise is commonly called as Jhum Cultivation.

Question 3.
What is meant by ozone hole? When does it develop every year? How are CFC’s responsible for this?
Ozone hole is the thinning of ozone layer is stratosphere and it is marked over the Antartica region. It develops every year late August and early October.

In the stratosphere the VU rays act on the CFCs and release chlorine atoms. There chlorine atoms degrade the ozone layer by acting as a catalyst. Since the chlorine atom are not consumed in the reaction the CFCs have a permanent and continuing effect on ozone holes.

KSEEB Solutions

Question 4.
The figure given aside shows relative contributions of various green house gases to the total global warming.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 6
(i) Name the gases a and b.
(ii) Explain how increase in green house gases in earth’s atmosphere leads to melting of the caps.
(i) (a) N2O
(b) CH4
(ii) Increase in green house gases (GHGs) results in increased green house flux or trapping long wave radiations and sending them back to earth. It increases atmospheric temperature called global warming. High atmospheric temperature results in melting of ice caps and glaciers.

Question 5.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 7
The above diagram shows simplified biogeochemical cycle.
(a) Name the compound whose cycle is deposited
(b) In what way do vehicles add this compound to the atmosphere?
(c) What adverse effect does it excess have on the environment?
(d) Cite an event which depicts this effect in modern times.
(e) Suggest 2 ways of reducing this effect.
(a) CO2 cycle
(b) By burning fossil fuel
(c) Global Warming
(d) Melting of glaciers and slow rise in sea level, submerging of low lying islands.

  • Limiting the use of fossil fuels
  • Increase the vegetation cover

Question 6.
2nd PUC Biology Question Bank Chapter 16 Environmental Issues 8
Study the graph and answer the following questions
(1) What is the relationship between dissolved oxygen and biochemical oxygen demand (BOD)
(2) Mention their effect on aquatic life of the river.

  1. The dissolved oxygen content is inversely proportional to BOD i.e. when BOD rises, the content of dissolved oxygen decreases and vice versa.
  2. When BOD is high, the aerobic aquatic organism will die due to decreased availability of disolved oxygen. When BOD is low, the content of dissolved oxygen becomes high. In clear water, aerobic aquatic organisms reappear.

2nd PUC Biology Environmental Issues Five Marks Questions

Question 1.
Differentiate between Biological magnification and eutrophication. (CBSE2007)

Biological Magnification Eutrophication
(a) It is increasing concentration of a persistent pollutant With the rise in trophic level. It is nutrient enrichment of a water body.
(b) It occurs both in terrestial and aquatic ecosystem Occurs only in aquatic ecosystem
(c) There is no excessive growth There is excessive growth of algae
(d) Organic loading is absent Organic loading occurs in water body.
(e) The higher order consumers are harmed most. The whole aquatic ecosystem is damaged.

Question 2.
Given below are the sources of pollution and their effects. Using this information, fill the spaces in the given box. Each pollutant may have more than one source and may show more than one effect. Pollutant source: Automobile exhaust, Burning of fossil fuels, refrigerant, agricultural field, lire extinguisher, paint solvents, Deforestation, plastic foam.
Effect: Photo-chemical smog, Acid deposition, global warming, Depletion of ozone.

Name of pollutant Source Effect
  1. CFC
  2. Suspended particulate matter (SPM)
  3. Oxides of nitrogen
  4. Sulphur dioxide
  5. Methane (CH4)


  • CFC: Sources – Refrigerant, Fire extinguisher, paint solvents, plastic foam.
    Effects: Depletion of ozone, global warming
  • SPM: Sources – Automobile exhaust, Burning of fossil fuel
    Effect: Photochemical smog.
  • Oxides: Source-Automobile exhaust, Burning of nitrogen of fossil fuel, Agricultural field.
    Effect: Photochemical smog, Acid-deposition, global warming.
  • Sulphur dioxide: Source – Automobile exhaust, Burning of fossil fuel.
    Effect: Acid deposition.
  • Methane Sources: Agricultural field, Burning of fossil fuel.
    Effect: global warming.

KSEEB Solutions

Question 3.
Differentiate between
(a) BOD and COD
(b) Montreal and Kyoto protocols.
(a) BOD and COD

(i) It is biochemical oxygen demand It is chemical oxygen demand.
(ii) Its value is lower Its value is higher
(iii) It measures oxygen demand for the completion of degradation of organic matter. It measures oxygen demand for oxidising all the red­uced substances, whether organic or inorganic.
(iv) It employes decompose microbes It employs potassium permanganate or potassium diehromate.

(b) Montreal and Kyoto protocols.

Montreal Protocol Kyoto protocols
(i) It is related to a reduction  in the production and consumption of CFC and other ODS. It is related to emission of CO2 and other greenhouse gases
(ii) The protocol was signed in 1987 (ii) This was signed in 1997
(iii) It was followed by Helsinki decla­ration to phase out CFCs and halons. The road map was prepared to help the actions to replace CFC and ODS. (iii) It has been followed by Bati conference in 2007 Road map has been prepared to reduce emission of green house gases by 2012.

(a) What is meant by deforestation? Mention the cause of it.
(b) Why is CNG preferred to diesel/petrol
It is the conversion of forest areas to non forest areas and ultimately to a desert.
(a) Causes of deforestation are

  • Conversions of forest land to agricultural land to produce food for* increasing population.
  • Cutting of trees for timber and wood
  • Jhumcultivation in the north-eastern states of India
  • Forest fires.


  • CNG burns most efficiently in the automobiles and leaves very little of it unburnt.
  • CNG cannot be adulterated like petrol/diesel
  • It cannot be siphoned by thieves
  • It is cheaper than petrol/diesel.

Question 5.
Why do you consider that integrated organic farming is more advantageous?
Integrated organic farming is a cyilical, zero-waste process, in which the waste materials from one process are used as nutrients or raw materials for the other process. The resources are utilized to the maximum and the efficiency of production is increased. Since the process support one another, it is an extremely economical and sustainable procedure. There is no need to depend on chemical fertilizers and pesticides as cattle dung is used as manure. Crop residues are decomposed and they are used as manure.
Dung of animals and crop residues are used to produce biogas, which satisfies the energy needs of the farm.

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