Sentence Correction (SC) | Re: Both the complexity of the phenomenon known as…700 level SC

Both the complexity of the phenomenon known as extinctionand 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
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