22. __________ play a key role in the transformation of rock to soil.
A.Cyanobacteia
B.Pectin decomposing bacteria
C.Nitrifying bacteria
D.De-nitrifying bacteria

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23. The groups of bacteria which have the ability to fix nitrogen from air to soil are
A.symbiotic
B.nonsymbiotic
C.both (a) and (b)
D.none of these

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24. The nitrogenase consists of
A.dinitrogenase
B.dinitrogenase reductase
C.both (a) and (b)
D.none of these

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25. The crops which are involved in nitrogen fixation are
A.alfalfa and clover
B.soybean
C.bean and lupine
D.all of these

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26. Denitrification may be distinguished as
A.dissimilative
B.assimilative
C.both (a) and (b)
D.blue baby syndrome

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27. The conversion of molecular nitrogen into ammonia is known as
A.nitrification
B.denitrification
C.nitrogen fixation
D.ammonification

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28. The breakdown of cattle manure in biogas is accomplished by which of the following type of bacteria?
A.Hydrolytic
B.Transitional
C.methanogenic
D.All of these

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