251.
Eutrophication of water bodies leading to killing of fishes is mainly due to non-availability of : A
light
B
essential minerals
C
oxygen
D
food
Answer :
oxygen
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252.
D.D.T. is A
a non-degradable pollutant
B
a bio-degradable pollutant
C
not a pollutant
D
an antibiotic
Answer :
a non-degradable pollutant
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253.
Which one of the following correctly represents an organism and its ecological niche A
Vallisneria and pond
B
Desert locust (Schistocerca) and desert
C
Plant lice (aphids) and leaf
D
Vultures and dense forest
Answer :
Vallisneria and pond
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254.
In which one of the following the BOD (Biochemical Oxygen Demand) of sewage (S), distillery effluent (DE), paper mill effluent (PE) and sugar mill effluent (SE), have been arranged in ascending order A
S < DE < PE < SE
B
SE < S < PE < DE
C
SE < PE < S < DE
D
PE < S < SE < DE
Answer :
SE < S < PE < DE
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255.
An ecosystem which can be easily damaged but ban recover after some time if damaging effect stops will having A
High stability and low resilience
B
Low stability and low resilience
C
High stability and high resilience
D
Low stability and high resilience
Answer :
Low stability and high resilience
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256.
Tropical dense forest are due to A
Low rainfall and low temperature
B
High rainfall and high temperature
C
Low rainfall and high temperature
D
High rainfall and high temperature
Answer :
High rainfall and high temperature
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257.
Which one of the following is not a bioindicator of water pollution A
Sewage fungus
B
Sludge - worms
C
Blood - worms
D
Stone files
Answer :
Stone files
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258.
Photochemical smog pollution does not contain A
Nitrogen dioxide
B
Carbon dioxide
C
PAN (peroxy acyl nitrate)
D
Ozone
Answer :
Carbon dioxide
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259.
Plants growing in dry and saline soil are called A
Xerophyte
B
Hydrophyte
C
Halophyte
D
Heliphyte
Answer :
Halophyte
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260.
Depletion of which gas in the atmosphere can lead to an increased incidence of skin cancers A
Nitrous oxide
B
Ozone
C
Ammonia
D
Methane
Answer :
Ozone
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