Text 1 Africa's Sahara region—once a lush ecosystem—began to dry out about 8,000 years ago. A change in Earth's orbit that affected climate has been posited as a cause of desertification, but archaeologist David Wright also attributes the shift to Neolithic peoples. He cites their adoption of pastoralism as a factor in the region drying out: the pastoralists' livestock depleted vegetation, prompting the events that created the Sahara Desert. Text 2 Research by Chris Brierley et al. challenges the idea that Neolithic peoples contributed to the Sahara's desertification. Using a climate-vegetation model, the team concluded that the end of the region's humid period occurred 500 years earlier than previously assumed. The timing suggests that Neolithic peoples didn't exacerbate aridity in the region but, in fact, may have helped delay environmental changes with practices (e.g., selective grazing) that preserved vegetation.

Question

Accepted Answer

By pointing out that given the revised timeline for the end of the Sahara's humid period, the Neolithic peoples' mode of subsistence likely didn't cause the region's desertification

Answer

By claiming that pastoralism was only one of many behaviors the Neolithic peoples took part in that may have contributed to the Sahara's changing climate

Answer

By insisting that pastoralism can have both beneficial and deleterious effects on a region's vegetation and climate

Answer

By asserting that more research needs to be conducted into factors that likely contributed to the desertification of the Sahara region

Text from Passage	Analysis
'Africa's Sahara region—once a lush ecosystem—began to dry out about 8,000 years ago.'	What it says: Sahara = lush → dry ~8K yrs ago What it does: Establishes timeline for environmental change What it is: Historical context
'A change in Earth's orbit that affected climate has been posited as a cause of desertification, but archaeologist David Wright also attributes the shift to Neolithic peoples.'	What it says: 2 causes proposed: orbital change + Wright = Neolithic peoples What it does: Introduces competing explanations, focusing on Wright's theory What it is: Main claim setup
'He cites their adoption of pastoralism as a factor in the region drying out: the pastoralists' livestock depleted vegetation, prompting the events that created the Sahara Desert.'	What it says: Wright's mechanism: pastoralism → livestock ate plants → desert What it does: Explains Wright's causal theory in detail What it is: Supporting evidence/mechanism
'Research by Chris Brierley et al. challenges the idea that Neolithic peoples contributed to the Sahara's desertification.'	What it says: Brierley team = challenges Neolithic peoples theory What it does: Presents opposing viewpoint to Wright's claim What it is: Counter-argument introduction
'Using a climate-vegetation model, the team concluded that the end of the region's humid period occurred 500 years earlier than previously assumed.'	What it says: Model shows humid period ended 500 yrs earlier than thought What it does: Provides key evidence for the challenge What it is: Research methodology and findings
'The timing suggests that Neolithic peoples didn't exacerbate aridity in the region but, in fact, may have helped delay environmental changes with practices (e.g., selective grazing) that preserved vegetation.'	What it says: New timeline = Neolithic peoples didn't worsen + maybe helped delay via selective grazing What it does: Explains implications of the revised timing What it is: Conclusion and alternative interpretation

Text 1Africa's Sahara region—once a lush ecosystem—began to dry out about 8,000 years ago. A change in Earth's orbit that...

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