51.
Which one of the following statements is correct? A
Both Azotobacter and Rhizobium fix atmospheric nitrogen in root nodules of plants
B
Cyanobacteria such as Anabaena and Nostoc are important mobilizers of phosphates and for plant nutrition in soil
C
At present it is not possible to grow maize without chemical fertilizers
D
Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies
Answer :
Extensive use of chemical fertilizers may lead to eutrophication of nearby water bodies
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52.
Which one of the following is the correct percentage of the two (out of the total of 4) green house gases that contribute to the total global warming? A
CFCs 14%, Methane 20%
B
$$CO_2,$$ 40%, CFCs 30%
C
$$N_2O$$ 6%, $$CO_2$$ 86%
D
Methane 20%, $$N_2O$$ 18%
Answer :
CFCs 14%, Methane 20%
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53.
The important of ecosystem lies in A
Energy flow
B
Cycling of materials
C
A and B both
D
None of the above
Answer :
A and B both
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54.
Most hazardous metal pollutant of automobile exhaust is A
Hg
B
Cd
C
Pb
D
Cu
Answer :
Pb
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55.
In an aquatic environment, microscopic animals and plants are collectively knows as A
World Environment Day
B
World AIDS Day
C
World Women's Day
D
Worlds Polio Day
Answer :
Worlds Polio Day
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56.
Autecology refers to A
Plant ecology
B
Animal ecology
C
Ecological study of individual species
D
Ecological study of group of species, which is grown together
Answer :
Ecological study of individual species
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57.
Which one of the following is a wrong statement? A
Most of the forests have been lost in tropical areas
B
Ozone in upper part of atmosphere is harmful to animals
C
Greenhouse effect is a natural phenomenon
D
Eutrophication is a natural phenomenon in freshwater bodies
Answer :
Ozone in upper part of atmosphere is harmful to animals
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58.
Pond is an example of _________ ecosystem A
Artificial
B
Natural
C
Forest
D
Grassland
Answer :
Natural
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59.
Species separated by geographical barrier are called A
Allopatric
B
Sympatric
C
Sibling
D
Endemic
Answer :
Allopatric
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60.
The major source of BOD in the river Ganga is A
Leaf litter
B
Fishes
C
Human waste
D
Aquatic plants
Answer :
Human waste
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