41. The lowest layer of earth's atmosphere is

1. 1. troposphere

   
   
   

   2. stratosphere

   
   
   

   3. mesosphere

   
   
   

   4. ionosphere

   
   
   

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   NA

   Correct Option: A

   NA

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42. Ozone depletion in the stratosphere is mainly caused by

1. 1. SO₂

   
   
   

   2. NO₂

   
   
   

   3. NO

   
   
   

   4. chlorogluorocarbons

   
   
   

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   NA

   Correct Option: D

   NA

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43. Green house effect is accelerated by

1. 1. deforestation

   
   
   

   2. rapid industrialization

   
   
   

   3. increased transportation activity

   
   
   

   4. all of these

   
   
   

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   NA

   Correct Option: D

   NA

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44. Many people died in London in 1952 as result of air pollution producing

1. 1. mist

   
   
   

   2. fog

   
   
   

   3. smog

   
   
   

   4. sleet

   
   
   

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   NA

   Correct Option: C

   NA

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45. Which of the following is a man-made source of air pollution ?

1. 1. Automobile exhaust

   
   
   

   2. Forest fire

   
   
   

   3. Bacterial action in soil and swamp areas

   
   
   

   4. All of the above

   
   
   

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1. View Hint View Answer Discuss in Forum

   NA

   Correct Option: A

   NA

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