31. Sewage water can be purified by

A Aquatic plant
B Micro organism
C Penicillin
D Fishes
Answer :   Micro organism
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32. The molecular action of ultraviolet light is mainly reflected through

A Destruction of hydrogen bonds in DNA
B Phtodynamic action
C Formation of pyramidine
D Formation of sticky metaphase
Answer :   Destruction of hydrogen bonds in DNA
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33. The Air Prevention and Control of Pollution Act came into force in :

A 1981
B 1985
C 1990
D 1975
Answer :   1981
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34. Global warming can be controlled by:

A Reducing reforestation, increasing the use of fossil fuel
B Increasing deforestation, slowing down the growth of human population
C Increasing deforestation, reducing efficiency of energy usage
D Reducing deforestation, cutting down use of fossil fuel
Answer :   Reducing deforestation, cutting down use of fossil fuel
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35. In plant succession last community is called

A Ecotone
B Climaxcommunity
C Seral community
D Ecosystem
Answer :   Climaxcommunity
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36. Energy enters in a food chain through

A Producers
B Primary consumers
C Secondary consumers
D Tertiary consumers
Answer :   Producers
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37. Which one of the following statements is not valid for aerosols?

A They alter rainfall and monsoon patterns
B They cause increased agricultural productivity
C They have negative impact on agricultural land
D They are harmful to human health
Answer :   They cause increased agricultural productivity
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38. The maximum energy is stored at following tropical level in any ecosystem

A Producers
B Herbevores
C Carnivores
D Top carnivores
Answer :   Producers
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39. Rachel Carson's famous book "Silent Spring" is related to :

A Noise pollution
B Population explosion
C Ecosystem management
D Pesticide pollution
Answer :   Pesticide pollution
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40. A major component of gobar gas is

A Ammonia
B Methane
C Ethane
D Butane
Answer :   Methane
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