Environmental Issues

Biology
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BOD stands for

A
Biological organism death
B
Biochemical organic matter decay
C
Biotic oxidation demand
D
Biochemical oxygen demand
Medium
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Freon gas causing stratospheric  depletion is mainly released from

A
Refrigerator
B
Automobile
C
Thermal power plant
D
Steel industry
Medium
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Which one of the following is the correct percentage of (the two out of four) greenhouse gases that contribute to the total global warming?

A
NO 6%, CO 86%
B
Methane 20%, NO 18%
C
CFC 14%, Methane 20%
D
CO 40%, CFC 30%
Medium
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Why is the concentration of ozone less over the north and south poles?

A
CFC's accumulate only in area where the air is cold.
B
CFC use is highest in these areas.
C
CFC's stick to frozen water vapour and are able to act as catalysts.
D
UV rays are stronger in the atmosphere.
Medium
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The purpose of biological treatment of waste-water is to

A
Reduce BOD
B
Increase BOD
C
Reduce sedimentation
D
Increase sedimentation
Medium
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Protective layer of ozone in the atmosphere exists in which layer?

A
Troposphere
B
Lonosphere
C
Stratosphere
D
Atmosphere
Medium
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Good ozone is found in 

A
Atmosphere
B
Biosphere
C
Stratosphere
D
Ozonosphere
Medium
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Biochemical Oxygen Demand (BOD) in a river water

A
Remains unchanged when algal bloom occurs
B
Has no relationship with concentration of oxygen in the water
C
Gives a measure of salmonella in the water
D
Increases when sewage gets mixed with river water
Medium
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