GMAT Sentence Correction (SC) | #Top150 SC: The Middle Stone Age, extended for 200,000 years from

A. extended for 200,000 years from 300,000 BC TO 500,000 BC, is marked by the intelligent manufacture by the tribals of glues used for fixing honed heads to the spears and arrows, a complex process that, in the absence empirical means of observation,requires far more mental and abstract perception than - Incorrect - 'requires' should be used in past tense.

B. was extended for 200,000 years from 300,000 BC TO 500,000 BC, marked by the intelligent manufacture by the tribal of glues used for fixing
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