Selina Textbook Solutions: Preventive Measures | Geography Class 9 ICSE PDF Download

 Page 1


Preventive Measures 
Exercises 
I. Short Answer Questions. 
Question 1. 
State two negative effects of vehicular emissions. 
Answer: 
Vehicular emissions have two negative effects on the environment : One is global 
climate change and the other is air pollution and its negative health repercussions. 
Question 2. 
Name any two gases emitted by vehicular emissions. 
Answer: 
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides 
(NO x). 
Question 3. 
What is meant by carpooling ? 
Answer: 
Carpooling refers to the sharing of car journeys by persons travelling on the same route. 
Question 4. 
Name any three modes of public transport used in India. 
Answer: 
Buses, trams, passenger trains and metro rails. 
Question 5. 
What is a ‘No Smoking Zone’ ? 
Answer: 
Smoking does not just harm the smoker but also the people nearby, who breathe in the 
smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has 
shown that concentration of second-hand tobacoo smoke (the smoke exhaled by 
smoekers) in many outdoor areas is often as high or higher than in some indoor areas 
and the risks posed by such outdoor exposure are well beyond generally ecceptd norms 
when large numbers of people are involuntarily exposed. Therefore, the passive 
smokers or those who unavoidably breathe in second-hand tabacoo at public places 
have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in 
children. 
To save such passive smokers and discourage smokers from the ill effect of the 
smoking in public places ‘No Smoking Zone’ has been created. 
Page 2


Preventive Measures 
Exercises 
I. Short Answer Questions. 
Question 1. 
State two negative effects of vehicular emissions. 
Answer: 
Vehicular emissions have two negative effects on the environment : One is global 
climate change and the other is air pollution and its negative health repercussions. 
Question 2. 
Name any two gases emitted by vehicular emissions. 
Answer: 
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides 
(NO x). 
Question 3. 
What is meant by carpooling ? 
Answer: 
Carpooling refers to the sharing of car journeys by persons travelling on the same route. 
Question 4. 
Name any three modes of public transport used in India. 
Answer: 
Buses, trams, passenger trains and metro rails. 
Question 5. 
What is a ‘No Smoking Zone’ ? 
Answer: 
Smoking does not just harm the smoker but also the people nearby, who breathe in the 
smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has 
shown that concentration of second-hand tobacoo smoke (the smoke exhaled by 
smoekers) in many outdoor areas is often as high or higher than in some indoor areas 
and the risks posed by such outdoor exposure are well beyond generally ecceptd norms 
when large numbers of people are involuntarily exposed. Therefore, the passive 
smokers or those who unavoidably breathe in second-hand tabacoo at public places 
have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in 
children. 
To save such passive smokers and discourage smokers from the ill effect of the 
smoking in public places ‘No Smoking Zone’ has been created. 
Question 6. 
What are Fossil Fuels ? 
Answer: 
Fossil fuels refer to buried, combustible deposits of organic materials, formed from 
decayed plants and animals that have been converted to crude oil, coal and natural gas 
by exposure to heat and pressure in the earth’s crust over hundreds of millions of years. 
Question 7. 
State why should we use fossil fuels judiciously. 
Answer: 
Fossil fuels are non-renewable source of energy. As a result of growing demand fossil 
fuels are being depleted at a rate of 100,000 times faster than they are being formed. At 
the present rate of usage, the coal reserves are likely to last for about 200 years. 
Similarly, at the present rate of usage, the world’s crude oil reserves would be 
exhausted in just 50 years. These resources are non-renewable and take millions of 
years to form. It is essential, therefore, to reduce dependence on such energy 
resources and explore and exploit the enormous potential of alternative sources of 
energy like solar energy, tidal energy, wind energy, geothermal energy and biomass 
based energy. They are not only renewable sources of energy but are environmentally 
clean and safe to use. 
Question 8. 
State any three measures to save energy. 
Answer: 
1. Use extra blankets and sweaters instead of using room heaters. Likewise, in 
summer, dress in light, cotton clothes to save on air conditioning costs and 
energy. 
2. Make sure that the houses are well insulated and, if heated or cooled, windows or 
doors are not left open. Raise shades on winter days, lower them in the summer. 
Seal all leaks. Block windows and doors with weather-strip tape and install blinds 
to reduce outside heat transfer. 
3. Use a low-flow shower head, to reduce water consumption and energy usage to 
heat the water. 
Question 9. 
What is Organic Farming ? 
Answer: 
According to Food and Agricultural Organisation (FAO) “Organic agriculture is a unique 
production management system which promotes and enhances agro-ecosystem health, 
including biodiversity, biological cycles and soil biological activity, and this is 
accomplished by using on-farm agronomic, biological and mechanical methods in 
exclusion of all synthetic off-farm inputs”. 
 
Page 3


Preventive Measures 
Exercises 
I. Short Answer Questions. 
Question 1. 
State two negative effects of vehicular emissions. 
Answer: 
Vehicular emissions have two negative effects on the environment : One is global 
climate change and the other is air pollution and its negative health repercussions. 
Question 2. 
Name any two gases emitted by vehicular emissions. 
Answer: 
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides 
(NO x). 
Question 3. 
What is meant by carpooling ? 
Answer: 
Carpooling refers to the sharing of car journeys by persons travelling on the same route. 
Question 4. 
Name any three modes of public transport used in India. 
Answer: 
Buses, trams, passenger trains and metro rails. 
Question 5. 
What is a ‘No Smoking Zone’ ? 
Answer: 
Smoking does not just harm the smoker but also the people nearby, who breathe in the 
smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has 
shown that concentration of second-hand tobacoo smoke (the smoke exhaled by 
smoekers) in many outdoor areas is often as high or higher than in some indoor areas 
and the risks posed by such outdoor exposure are well beyond generally ecceptd norms 
when large numbers of people are involuntarily exposed. Therefore, the passive 
smokers or those who unavoidably breathe in second-hand tabacoo at public places 
have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in 
children. 
To save such passive smokers and discourage smokers from the ill effect of the 
smoking in public places ‘No Smoking Zone’ has been created. 
Question 6. 
What are Fossil Fuels ? 
Answer: 
Fossil fuels refer to buried, combustible deposits of organic materials, formed from 
decayed plants and animals that have been converted to crude oil, coal and natural gas 
by exposure to heat and pressure in the earth’s crust over hundreds of millions of years. 
Question 7. 
State why should we use fossil fuels judiciously. 
Answer: 
Fossil fuels are non-renewable source of energy. As a result of growing demand fossil 
fuels are being depleted at a rate of 100,000 times faster than they are being formed. At 
the present rate of usage, the coal reserves are likely to last for about 200 years. 
Similarly, at the present rate of usage, the world’s crude oil reserves would be 
exhausted in just 50 years. These resources are non-renewable and take millions of 
years to form. It is essential, therefore, to reduce dependence on such energy 
resources and explore and exploit the enormous potential of alternative sources of 
energy like solar energy, tidal energy, wind energy, geothermal energy and biomass 
based energy. They are not only renewable sources of energy but are environmentally 
clean and safe to use. 
Question 8. 
State any three measures to save energy. 
Answer: 
1. Use extra blankets and sweaters instead of using room heaters. Likewise, in 
summer, dress in light, cotton clothes to save on air conditioning costs and 
energy. 
2. Make sure that the houses are well insulated and, if heated or cooled, windows or 
doors are not left open. Raise shades on winter days, lower them in the summer. 
Seal all leaks. Block windows and doors with weather-strip tape and install blinds 
to reduce outside heat transfer. 
3. Use a low-flow shower head, to reduce water consumption and energy usage to 
heat the water. 
Question 9. 
What is Organic Farming ? 
Answer: 
According to Food and Agricultural Organisation (FAO) “Organic agriculture is a unique 
production management system which promotes and enhances agro-ecosystem health, 
including biodiversity, biological cycles and soil biological activity, and this is 
accomplished by using on-farm agronomic, biological and mechanical methods in 
exclusion of all synthetic off-farm inputs”. 
 
II. Long Answer Questions : 
Question 1. 
With reference to vehicular pollution in cities, state the significance of the following as a 
preventive measure. 
1. Carpool 
2. Public Transportation 
Answer: 
1. Carpool : 
(a) It reduces air pollution by reducing the number of vehicles on the road and 
thereby, cutting down the vehicular emissions. 
(b) It helps to save money in buying fuel and maintenance cost of cars. 
(c) It helps to save petrol and diesel and thereby, save foreign exchange that goes 
into buying these fuels. 
(d) It reduces traffic congestion on the roads and thereby prevents traffic jams, 
reduces fuel consumption and commuting time and the cost of road repairs. 
(e) It helps to use commuting time in useful pursuits. 
2. Public Transportation : 
(a) It reduces damage to the environment by reducing emissions. For example, 
one bus emits far fewer fumes than 20 cars. 
(b) It requires 1/5 th energy per passenger per km compared to road based 
transport system. It therefore, reduces fuel consumption and thus helps to save 
foreign exchange used in buying petrol and diesel. 
(c) It causes less noise, no air pollution and is eco-friendly transport system. 
(d) It helps to save money spent on maintenance of personal vehicles. It avoids 
the need to find parking space for private vehicles. Thus, reduces congenstion on 
roads. 
Question 2. 
With reference to smoking, answer the following : 
1. How does smoking harm passive smokers ? 
2. Name any two legal provision meant to deter smoking. 
3. State any three advantages of having a ‘No Smoking Zone’. 
Answer: 
1. Smoking does not just harm the smoker but also the people nearby, who breathe 
in the smoke exhaled by the smokers and are called passive smokers. Recent 
research has shown that concentration of second hand tobacco smoke in many 
outdoor areas is often as high or higher than in some indoor areas such outdoor 
Page 4


Preventive Measures 
Exercises 
I. Short Answer Questions. 
Question 1. 
State two negative effects of vehicular emissions. 
Answer: 
Vehicular emissions have two negative effects on the environment : One is global 
climate change and the other is air pollution and its negative health repercussions. 
Question 2. 
Name any two gases emitted by vehicular emissions. 
Answer: 
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides 
(NO x). 
Question 3. 
What is meant by carpooling ? 
Answer: 
Carpooling refers to the sharing of car journeys by persons travelling on the same route. 
Question 4. 
Name any three modes of public transport used in India. 
Answer: 
Buses, trams, passenger trains and metro rails. 
Question 5. 
What is a ‘No Smoking Zone’ ? 
Answer: 
Smoking does not just harm the smoker but also the people nearby, who breathe in the 
smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has 
shown that concentration of second-hand tobacoo smoke (the smoke exhaled by 
smoekers) in many outdoor areas is often as high or higher than in some indoor areas 
and the risks posed by such outdoor exposure are well beyond generally ecceptd norms 
when large numbers of people are involuntarily exposed. Therefore, the passive 
smokers or those who unavoidably breathe in second-hand tabacoo at public places 
have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in 
children. 
To save such passive smokers and discourage smokers from the ill effect of the 
smoking in public places ‘No Smoking Zone’ has been created. 
Question 6. 
What are Fossil Fuels ? 
Answer: 
Fossil fuels refer to buried, combustible deposits of organic materials, formed from 
decayed plants and animals that have been converted to crude oil, coal and natural gas 
by exposure to heat and pressure in the earth’s crust over hundreds of millions of years. 
Question 7. 
State why should we use fossil fuels judiciously. 
Answer: 
Fossil fuels are non-renewable source of energy. As a result of growing demand fossil 
fuels are being depleted at a rate of 100,000 times faster than they are being formed. At 
the present rate of usage, the coal reserves are likely to last for about 200 years. 
Similarly, at the present rate of usage, the world’s crude oil reserves would be 
exhausted in just 50 years. These resources are non-renewable and take millions of 
years to form. It is essential, therefore, to reduce dependence on such energy 
resources and explore and exploit the enormous potential of alternative sources of 
energy like solar energy, tidal energy, wind energy, geothermal energy and biomass 
based energy. They are not only renewable sources of energy but are environmentally 
clean and safe to use. 
Question 8. 
State any three measures to save energy. 
Answer: 
1. Use extra blankets and sweaters instead of using room heaters. Likewise, in 
summer, dress in light, cotton clothes to save on air conditioning costs and 
energy. 
2. Make sure that the houses are well insulated and, if heated or cooled, windows or 
doors are not left open. Raise shades on winter days, lower them in the summer. 
Seal all leaks. Block windows and doors with weather-strip tape and install blinds 
to reduce outside heat transfer. 
3. Use a low-flow shower head, to reduce water consumption and energy usage to 
heat the water. 
Question 9. 
What is Organic Farming ? 
Answer: 
According to Food and Agricultural Organisation (FAO) “Organic agriculture is a unique 
production management system which promotes and enhances agro-ecosystem health, 
including biodiversity, biological cycles and soil biological activity, and this is 
accomplished by using on-farm agronomic, biological and mechanical methods in 
exclusion of all synthetic off-farm inputs”. 
 
II. Long Answer Questions : 
Question 1. 
With reference to vehicular pollution in cities, state the significance of the following as a 
preventive measure. 
1. Carpool 
2. Public Transportation 
Answer: 
1. Carpool : 
(a) It reduces air pollution by reducing the number of vehicles on the road and 
thereby, cutting down the vehicular emissions. 
(b) It helps to save money in buying fuel and maintenance cost of cars. 
(c) It helps to save petrol and diesel and thereby, save foreign exchange that goes 
into buying these fuels. 
(d) It reduces traffic congestion on the roads and thereby prevents traffic jams, 
reduces fuel consumption and commuting time and the cost of road repairs. 
(e) It helps to use commuting time in useful pursuits. 
2. Public Transportation : 
(a) It reduces damage to the environment by reducing emissions. For example, 
one bus emits far fewer fumes than 20 cars. 
(b) It requires 1/5 th energy per passenger per km compared to road based 
transport system. It therefore, reduces fuel consumption and thus helps to save 
foreign exchange used in buying petrol and diesel. 
(c) It causes less noise, no air pollution and is eco-friendly transport system. 
(d) It helps to save money spent on maintenance of personal vehicles. It avoids 
the need to find parking space for private vehicles. Thus, reduces congenstion on 
roads. 
Question 2. 
With reference to smoking, answer the following : 
1. How does smoking harm passive smokers ? 
2. Name any two legal provision meant to deter smoking. 
3. State any three advantages of having a ‘No Smoking Zone’. 
Answer: 
1. Smoking does not just harm the smoker but also the people nearby, who breathe 
in the smoke exhaled by the smokers and are called passive smokers. Recent 
research has shown that concentration of second hand tobacco smoke in many 
outdoor areas is often as high or higher than in some indoor areas such outdoor 
exposure are well beyond generally are involuntarily exposed. Therefore, the 
passive smokers or those who unavoidably breathe in second-hand tobacco at 
public places have such as lung cancer, asthma, bronchitis and sudden infant 
death syndrome in children. 
2. (a) As a preventive measure, a mandatory specific statutory health warning on 
cigarette packs was introduced in 1975. Realising the seriousness of the problem. 
(b) Smoking in public places was prohibited nationwide from October 2 under the 
Prohibition of smoking in Public Places Rules 2008. The smoking ban pertains to 
public places, which include auditoriums, cinemas, hospitals, public transport 
(aircraft, buses, trains, metros, taxis) and their related facilities (airports, bus 
stands, railway stations), restaurants, hotels, bars, pubs, amusement centers, 
offices, libraries, courts, post offices, markets, shopping malls, canteens, 
educational institutions and parks. 
3. Advantages of No Smoking Zone are the following : 
(a) It reduces the possibility of second-hand tobacco smoke being inhaled by non-
smokers. 
(b) It reduces air pollution. Areas which have prohibited smoking have been found 
to have better indoor air quality as opposed to areas where smoking is allowed. 
(c) It reduces healthcare costs by reducing the chances of diseases caused by 
smoking. 
(d) It reduces the chances of influencing others, especially the youth, to take on 
the habit of smoking. 
Question 3. 
With reference to Organic Farming state the following : 
1. Four principles of Organic Farming. 
2. Main characteristics of Organic Farming. 
3. Importance of Organic Farming. 
Answer: 
1. The four Principles of Organic Farming are : 
(a) Organic should sustain and enhance the health of soil, plants, animals and 
humans as one and indivisible. 
(b) Organic farming should be based on living ecological systems and cycles, 
work with them, emulate them and help sustain them. 
(c) Organic agriculture should build on relationships that ensure fairness with 
regard to the common environment and life opportunities. 
(d) Organic farming should be managed in a precautionary and responsible 
manner to protect the health and well being of current and future generations and 
the environment. 
2. The main characteristics of organic farming are the following : 
(a) Protecting the long term fertility of soils by maintaining organic matter levels, 
and creating optimized conditions for biological activity within the soil. 
(b) Providing crop nutrients indirectly using relatively insoluble nutrient sources 
Page 5


Preventive Measures 
Exercises 
I. Short Answer Questions. 
Question 1. 
State two negative effects of vehicular emissions. 
Answer: 
Vehicular emissions have two negative effects on the environment : One is global 
climate change and the other is air pollution and its negative health repercussions. 
Question 2. 
Name any two gases emitted by vehicular emissions. 
Answer: 
Carbon monoxide (CO) and a large share of the hydrocarbonx (HC), nitrogen oxides 
(NO x). 
Question 3. 
What is meant by carpooling ? 
Answer: 
Carpooling refers to the sharing of car journeys by persons travelling on the same route. 
Question 4. 
Name any three modes of public transport used in India. 
Answer: 
Buses, trams, passenger trains and metro rails. 
Question 5. 
What is a ‘No Smoking Zone’ ? 
Answer: 
Smoking does not just harm the smoker but also the people nearby, who breathe in the 
smoke exhaled by the smokers and are called ‘passive smokers’. Recent research has 
shown that concentration of second-hand tobacoo smoke (the smoke exhaled by 
smoekers) in many outdoor areas is often as high or higher than in some indoor areas 
and the risks posed by such outdoor exposure are well beyond generally ecceptd norms 
when large numbers of people are involuntarily exposed. Therefore, the passive 
smokers or those who unavoidably breathe in second-hand tabacoo at public places 
have such as lung cancer, asthma, bronchitis and sudden infant death syndrome in 
children. 
To save such passive smokers and discourage smokers from the ill effect of the 
smoking in public places ‘No Smoking Zone’ has been created. 
Question 6. 
What are Fossil Fuels ? 
Answer: 
Fossil fuels refer to buried, combustible deposits of organic materials, formed from 
decayed plants and animals that have been converted to crude oil, coal and natural gas 
by exposure to heat and pressure in the earth’s crust over hundreds of millions of years. 
Question 7. 
State why should we use fossil fuels judiciously. 
Answer: 
Fossil fuels are non-renewable source of energy. As a result of growing demand fossil 
fuels are being depleted at a rate of 100,000 times faster than they are being formed. At 
the present rate of usage, the coal reserves are likely to last for about 200 years. 
Similarly, at the present rate of usage, the world’s crude oil reserves would be 
exhausted in just 50 years. These resources are non-renewable and take millions of 
years to form. It is essential, therefore, to reduce dependence on such energy 
resources and explore and exploit the enormous potential of alternative sources of 
energy like solar energy, tidal energy, wind energy, geothermal energy and biomass 
based energy. They are not only renewable sources of energy but are environmentally 
clean and safe to use. 
Question 8. 
State any three measures to save energy. 
Answer: 
1. Use extra blankets and sweaters instead of using room heaters. Likewise, in 
summer, dress in light, cotton clothes to save on air conditioning costs and 
energy. 
2. Make sure that the houses are well insulated and, if heated or cooled, windows or 
doors are not left open. Raise shades on winter days, lower them in the summer. 
Seal all leaks. Block windows and doors with weather-strip tape and install blinds 
to reduce outside heat transfer. 
3. Use a low-flow shower head, to reduce water consumption and energy usage to 
heat the water. 
Question 9. 
What is Organic Farming ? 
Answer: 
According to Food and Agricultural Organisation (FAO) “Organic agriculture is a unique 
production management system which promotes and enhances agro-ecosystem health, 
including biodiversity, biological cycles and soil biological activity, and this is 
accomplished by using on-farm agronomic, biological and mechanical methods in 
exclusion of all synthetic off-farm inputs”. 
 
II. Long Answer Questions : 
Question 1. 
With reference to vehicular pollution in cities, state the significance of the following as a 
preventive measure. 
1. Carpool 
2. Public Transportation 
Answer: 
1. Carpool : 
(a) It reduces air pollution by reducing the number of vehicles on the road and 
thereby, cutting down the vehicular emissions. 
(b) It helps to save money in buying fuel and maintenance cost of cars. 
(c) It helps to save petrol and diesel and thereby, save foreign exchange that goes 
into buying these fuels. 
(d) It reduces traffic congestion on the roads and thereby prevents traffic jams, 
reduces fuel consumption and commuting time and the cost of road repairs. 
(e) It helps to use commuting time in useful pursuits. 
2. Public Transportation : 
(a) It reduces damage to the environment by reducing emissions. For example, 
one bus emits far fewer fumes than 20 cars. 
(b) It requires 1/5 th energy per passenger per km compared to road based 
transport system. It therefore, reduces fuel consumption and thus helps to save 
foreign exchange used in buying petrol and diesel. 
(c) It causes less noise, no air pollution and is eco-friendly transport system. 
(d) It helps to save money spent on maintenance of personal vehicles. It avoids 
the need to find parking space for private vehicles. Thus, reduces congenstion on 
roads. 
Question 2. 
With reference to smoking, answer the following : 
1. How does smoking harm passive smokers ? 
2. Name any two legal provision meant to deter smoking. 
3. State any three advantages of having a ‘No Smoking Zone’. 
Answer: 
1. Smoking does not just harm the smoker but also the people nearby, who breathe 
in the smoke exhaled by the smokers and are called passive smokers. Recent 
research has shown that concentration of second hand tobacco smoke in many 
outdoor areas is often as high or higher than in some indoor areas such outdoor 
exposure are well beyond generally are involuntarily exposed. Therefore, the 
passive smokers or those who unavoidably breathe in second-hand tobacco at 
public places have such as lung cancer, asthma, bronchitis and sudden infant 
death syndrome in children. 
2. (a) As a preventive measure, a mandatory specific statutory health warning on 
cigarette packs was introduced in 1975. Realising the seriousness of the problem. 
(b) Smoking in public places was prohibited nationwide from October 2 under the 
Prohibition of smoking in Public Places Rules 2008. The smoking ban pertains to 
public places, which include auditoriums, cinemas, hospitals, public transport 
(aircraft, buses, trains, metros, taxis) and their related facilities (airports, bus 
stands, railway stations), restaurants, hotels, bars, pubs, amusement centers, 
offices, libraries, courts, post offices, markets, shopping malls, canteens, 
educational institutions and parks. 
3. Advantages of No Smoking Zone are the following : 
(a) It reduces the possibility of second-hand tobacco smoke being inhaled by non-
smokers. 
(b) It reduces air pollution. Areas which have prohibited smoking have been found 
to have better indoor air quality as opposed to areas where smoking is allowed. 
(c) It reduces healthcare costs by reducing the chances of diseases caused by 
smoking. 
(d) It reduces the chances of influencing others, especially the youth, to take on 
the habit of smoking. 
Question 3. 
With reference to Organic Farming state the following : 
1. Four principles of Organic Farming. 
2. Main characteristics of Organic Farming. 
3. Importance of Organic Farming. 
Answer: 
1. The four Principles of Organic Farming are : 
(a) Organic should sustain and enhance the health of soil, plants, animals and 
humans as one and indivisible. 
(b) Organic farming should be based on living ecological systems and cycles, 
work with them, emulate them and help sustain them. 
(c) Organic agriculture should build on relationships that ensure fairness with 
regard to the common environment and life opportunities. 
(d) Organic farming should be managed in a precautionary and responsible 
manner to protect the health and well being of current and future generations and 
the environment. 
2. The main characteristics of organic farming are the following : 
(a) Protecting the long term fertility of soils by maintaining organic matter levels, 
and creating optimized conditions for biological activity within the soil. 
(b) Providing crop nutrients indirectly using relatively insoluble nutrient sources 
which are made available to the plant by the action of soil micro-organisms. 
(c) Maintaining nitrogen self-sufficiency through the use of legumes and biological 
nitrogen fixation, as well as effective recycling of organic materials including crop 
residues and livestock manures. 
(d) Preventing weeds, disease and pests by relying primarily on crop rotations, 
natural predators, diversity, organic manuring, resistant varieties and limited 
(preferably minimal) thermal, biological and chemical intervention. 
(e) Providing attentive care and management of livestock, paying full regard to 
their evolutionary adaptations, behavioural needs and animal welfare issues, with 
respect to nutrition, housing, health, breeding and rearing. 
(f) Careful attention to the impact of the farming system on the wider environment 
and the conservation of wildlife and natural habitats. 
3. Importance of Organic Farming are the following : 
(a) Organic faming promotes the use of crop rotations and cover crops, and 
encourages balanced host/predator relationships. 
(b) Organic residues and nutrients produced on the farm are recycled back to the 
soil. Cover crops and composted manure are used to maintain soil organic matter 
and fertility. 
(c) Preventative insect and disease control methods are practiced, including crop 
rotation, improved genetics and resistant varieties. Integrated pest and weed 
management, and soil conservation systems are valuable tools on an organic 
farm. 
Practice Questions 
Question 1. 
What purpose does an electrostatic precipitator serve? 
Answer: 
It is a device which removes unwanted chemicals from smoke after combustion takes 
place. The negative charged dust particles are drawn towards positively charged 
particles collector surface and by knocking the plates particles fall into a hopper tray for 
disposal. 
Question 2. 
In the context of reducing air pollutions, give the advantages of changing the process ; 
maintaining and modifying existing equipment. 
Answer: 
Change of modify the process of production in order to lower the atmospheric pollutants 
for example : 
1. The coal is washed before crushing it to reduce the fly ash emissions. 
2. The process of absorption can be used to remove gaseous air pollutants. In this 
process, gaseous air pollutants are removed by dissolution into a liquid solvent 
like water or caustic or acid solution. Absorption is used to remove sulphur 
dioxide, chlorine, ammonia, nitrogen oxides and hydrocarbons.