GMAT Sentence Correction (SC) | Re: Positing an enormous volcanic explosion at the end of the Permian peri

Topic Tested:Parallelism

Positing an enormous volcanic explosion at the end of the Permian period wouldexplain the presence of a buried crater,account for the presence of the element iridium (originating deep within the earth), and the presence of quartz having been shattered by high-impact shock waves. -- The original sentence is not parallel

A.account for the presence of the element iridium (originating deep within the earth), and the presence of quartz having been - Incorrect. Parallelism
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