Explanation
Correct answer: A.
Choice A is the best answer. Brierley et al.’s research directly challenges Wright’s claim that pastoralism turned the Sahara into a desert, suggesting that, in a Sahara that turned arid 500 years earlier than previously thought, pastoral practices may have actually “preserved vegetation” rather than depleting it.
Why the other choices are wrong
Choice B
Choice B is incorrect. Brierley et al.’s research actually disputes the idea that any Neolithic peoples’ behaviors, including pastoralism, could have contributed to the Sahara’s changing climate. In fact, their research implies that the Neolithic peoples’ practices did not “exacerbate aridity” (i.e., make things worse), but may have slowed environmental changes.
Choice C
Choice C is incorrect. Brierley et al.’s research does not acknowledge that pastoralism can have deleterious (i.e., negative) effects on a region’s vegetation and climate. It only describes one possible beneficial effect: preserving vegetation through practices like selective grazing.
Choice D
Choice D is incorrect. Brierley et al.’s research does not call for more research into factors that likely contributed to the desertification of the Sahara region.