Sentence Correction

i have one question here..regarding choice A ( dont assume i am questioning it but want to know what i am missing )

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If used repeatedly in the same place, one reason that certain pesticides can become ineffective is suggested by the finding that there are much larger populations of pesticide-degrading microbes in soils with a relatively long history of pesticide use than in soils that are free of such chemicals.
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is comparison is correct ?

there are much larger populations of pesticide-degrading microbes in soils with a relatively long history of pesticide use than in soils that are free of such chemicals.

I think , it should be like

there are much larger populations of pesticide-degrading microbes in soils with a relatively long history of pesticide use than those in soils that are free of such chemicals.


those - > much larger populations of pesticide-degrading microbes , does not we need it ?
can anyone explain ?

vineetbatra wrote:Thanks man, will check it out. There is an exception for an exception, everytime I see light at the end of the tunnel it turns out to be headlight of a train.

Vineet

Hopefully the train is a Boilermaker; then you are on a good path!

(A) CORRECT

(B) Wrong... the modified noun pesticide is not close to the modifier
(C) not Parallel