Both the complexity of the phenomenon known as extinction and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both in the field and in laboratories to clarify the relationships among the planet's many endangered life-forms.


(A) and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both

(B) and the vastness of the biosphere has prompted many scientists calling for a large increase in the number of biologists both working

(C) and the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists working both

(D) as well as the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists who both work

(E) as well as the vastness of the biosphere has prompted many scientists to call for a large increase in the number of biologists who work both

Why not 'E'... in E we have as well as ... has structure... parallelism is justified here also and also logically sound... please respond.

What is the source of this? Too easy for MGMAT. doesnt look like GMAT PREP

(A) and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both
incomplete sentence
(B) and the vastness of the biosphere has prompted many scientists calling for a large increase in the number of biologists both working
have not has
(C) and the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists working both
looks good to me
(D) as well as the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists who both work
as well as - no idiomatic
(E) as well as the vastness of the biosphere has prompted many scientists to call for a large increase in the number of biologists who work both
as well as - non idiomatic

Yes, the most evident problem with A is that it not a sentence at all! There is no verb in the entire sentence.
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Both the complexity of the phenomenon known as extinction and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both in the field and in laboratories to clarify the relationships among the planet's many endangered life-forms.

(A) and the vastness of the biosphere, having prompted many scientists to call for a large increase in the number of biologists working both - not a sentence
(B) and the vastness of the biosphere has prompted many scientists calling for a large increase in the number of biologists both working - subject verb agreement - both X&Y need plural
(C) and the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists working both - Correct
(D) as well as the vastness of the biosphere have prompted many scientists to call for a large increase in the number of biologists who both work - idiom issue
(E) as well as the vastness of the biosphere has prompted many scientists to call for a large increase in the number of biologists who work both - idiom issue

Answer C
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