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　　长江水稻 新题

　　Since the 1970s, archaeological sites in China's Yangtze River region have yielded evidence of sophisticated rice-farming societies that predate signs of rice cultivation elsewhere in East Asia by a thousand years. Before this evidence was discovered, it had generally been assumed that rice farming began farther to the south. This scenario was based both on the geographic range of wild or free-living rice, which was not thought to extend as far north as the Yangtze, and on archaeological records of very early domestic rice from Southeast Asia and India (now known to be not so old as first reported). Proponents of the southern-origin theory point out that early rice-farming societies along the Yangtze were already highly developed and that evidence for the first stage of rice cultivation is missing. They argue that the first hunter-gatherers to develop rice agriculture must have done so in this southern zone, within the apparent present-day geographic range of wild rice.

　　Yet while most strands of wild rice reported in a 1984 survey were concentrated to the south of the Yangtze drainage, two northern outlier populations were also discovered in provinces along the middle and lower Yangtze, evidence that the Yangtze wetlands may fall within both the present-day and the historical geographic ranges of rice's wild ancestor.

　　Which of the following, if true, would most clearly undermine the conclusion that the author makes based on the 1984 survey?

　　A. Areas south of the Yangtze basin currently have less wild-rice habitat than they once did.

　　B. Surveys since 1984 have shown wild rice populations along the upper Yangtze as well as along the middle and lower Yangtze.

　　C. The populations of wild rice along the Yangtze represent strains of wild rice that migrated to the north relatively recently.

　　D. Early rice-farming societies along the Yangtze were not as highly developed as archaeologists once thought.

　　E. In East Asia, the historical geographic range of wild rice was more extensive than the present-day geographic range is.

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