ENVIRONMENT AND ENVIRONMENTAL PROBLEMS - II : BRIEF ANSWERS

ANSWER IN BRIEF

*INDEX-TOPIC SEARCH

1. Mention types of environment with examples.
   

   ANS:

   
   
   • Physical environment : atmosphere, lithosphere, hydrosphere.
   • Biological environment : plants, animals, microorganisms.
   • Cultural environment : social traditions, economic, political.
     

   
   

   
   
2. Draw a chart showing types of environment.
   

   ANS:[SEE THE CHART]
   

   
   
   
3. Mention various environmental problems.
   

   ANS:Various environmental problems include :
   

   
   
   1. Decrease in habitat of wildlife
   2. Wastage of water
   3. Deforestation
   4. Soil erosion
   5. Desertification
   6. Depletion in biodiversity
      

   
   

   
   
4. Write a few sentences on air pollution.
   

   ANS:

   
   
   • The transparent layer of gases surrounding the earth is called atmosphere.
   • In balanced atmosphere the ratio of various gases is fixed.
   • When this balance is disturbed due to any reason, it is called air pollution.
   • The major reasons for air pollution are population explosion, urbanisation, industrialisation and heavy transportation.
     

   
   

   
   
5. Mention natural sources of air pollution.
   

   ANS:Natural sources of air pollution are : volcanoes, forest fire, storms, pollen grains, dust particles, decaying plants, lightening-induced chemical reactions, etc.
   

   
   
6. Mention man-made sources of air pollution.
   

   ANS:Man-made sources of air pollution are : Burning of firewood, burning of fossil fuels, industrialisation, agriculture, smoke from automobiles, aeroplanes, wars, atomic tests, deforestation, power stations, mining, oil refineries, etc.
   

   
   
7. Explain : Acid rain.
   

   ANS:

   
   
   • Combustion of fuels and industrial smoke add pollutant gases like NO₂, SO₂, etc. in the atmosphere.
   • These gases dissolve in moisture present in air and form acids like nitric acid and sulphuric acid.
   • When these acids come back to earth through rain, it is called Acid Rain.
   • Acid rain harms various organisms, monuments and buildings.
     

   
   

   
   
8. Explain : Greenhouse effect.
   

   ANS:

   
   
   • Gases like CO₂ and methane have the property of absorbing heat.
   • These gases, when present in atmosphere, absorb the heat of the sun rays reflected by the earth.
   • This results in the warming of earth's atmosphere.
   • This is called Green-House Effect.
   • Due to Greenhouse effect, the ice on polar regions may melt increasing the sea level.
     

   
   

   
   
9. Describe the methods for controlling gaseous pollutants.
   

   ANS:[Refer to Long Answer about prevention and control of air pollution]
   

   
   
10. Describe the methods for controlling particulate emissions.
    

    ANS:[Refer to Long Answer about prevention and control of air pollution]
    
    

    
    
11. Mention sources of water pollution.
    

    ANS:The sources of water pollution are :

    
    
    1. Industries
    2. Population explosion
    3. Sewage
    4. Pesticides and fertilisers
    5. Radioactive waste
    6. Oil(spillage of oil)
    7. Heavy metals
    8. Harmful microorganisms.
       

    
    

    
    
12. Describe sewage treatment.
    

    ANS:[Refer to Long Answer about prevention and control of water pollution]
    

    
    
13. Describe Oxidation Pond method.
    

    ANS:[Refer to Long Answer about prevention and control of water pollution]
    

    
    
14. List out pollutants causing land pollution.
    

    ANS:Pollutants causing land pollution are : fertilisers, ashes, coal, domestic waste, paper, card board, plastics, rubber, clothes, metals, glass, construction materials, dead bodies of animals, insecticides, radioactive waste, etc.
    

    
    
15. Mention effects of land pollution.
    

    ANS:

    
    
    • Agricultural land becomes less fertile.
    • Insoluble pesticides like DDT decrease the secretion of sex hormones as well as the calcium level.
    • Soil erosion occurs. The amount of soil washed out in 6 months can be sufficient to make bricks needed to construct houses of entire world.
      

    
    

    
    
16. Describe the main points for prevention and control of land pollution.
    

    ANS:

    
    
    • The pollutants can be decomposed and removed through biological processes.
    • They can be converted into organic fertilisers.
    • Non-decomposable waste can be used to fill up the pits.
    • Specific incinerators can be used for final disposal of waste.
      

    
    

    
    
17. Write about biodegradable pollutants.
    

    ANS:

    
    
    • The pollutants which can be decomposed by microorganisms are known as biodegradable pollutants.
    • Faecal matter, solid sewage waste, domestic waste, agricultural waste, paper, wood, clothes, etc. are biodegradable.
      

    
    

    
    
18. Write about non-biodegradable pollutants.
    

    ANS:

    
    
    • The pollutants which cannot be decomposed by microorganisms are known as non-biodegradable pollutants.
    • Pesticides like DDT, mercury, lead, aluminium, arsenic, plastics, etc. are non-biodegradable.
    • These pollutants remain for a long time in environment and enter the organisms through food chain and biogeochemical cycle.
    • Then they get accumulated in large amount in their bodies, a phenomenon called biomagnification.

    
    

    
    
19. Write a few points about environmental balance.
    

    ANS:

    
    
    • Environmental balance is essential for all organisms including man.
    • Pollution leads to the loss of environmental balance.
    • Environmental imbalance causes harmful effects on life of organisms.
    • Judicious use of non-renewable sources is necessary for the maintenance of environmental balance.
    • Personal as well as social awareness regarding environment like keeping one's surroundings clean automatically helps in the maintenance of balanced environment.
      

    
    

    
    
20. Write some points about conservation and protection of environment.
    

    ANS:

    
    
    • Conservation of environment means prevention of excessive use of such activities which provide individual and commercial benefits and lead to environmental damage.
    • Almost all countries in the world have made laws for the conservation of environment. These laws help protect and Conserve environment.
    • One should be aware of such laws to make it possible to protect and conserve environment.
      

    
    

    
    
21. Describe environmental problems.
    

    ANS:

    
    
    • Activities of man continuously disturb the environment and create various problems.
    • Population explosion, industrialization and other human activities create following problems :
      
      
      1. Decrease in habitat of wildlife
      2. Wastage of water
      3. Deforestation
      4. Soil erosion
      5. Desertification
      6. Depletion in biodiversity
         
      
      

    
    

    
    
22. Why do aquatic animals die in polluted water ?
    
    ANS: Due to pollution of water by domestic sewage and fertilizers there is an increase in nitrate and phosphate components. these components cause many fold growth of algae and other micro-organisms. This is called eutrophication and due to it the biological oxygen demand (BOD) of the aquatic ecosystem increases and the organisms die.