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题库 / GMATLA-CR-39
Charcoal from a hearth site in Colorado, 2,000 miles south of Alaska, is known to be 11,200 years old. Researchers reasoned that, since glaciers prevented human migration south from the Alaska-Siberia land bridge between 18,000 and 11,000 years ago, humans must have come to the Americas more than 18,000 years ago.
Which of the following pieces of new evidence would cast doubt on the conclusion drawn above?
Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.
Another campsite was found in New Mexico with remains dated at 16,000 years old.
A computer simulation of glacial activity showed that it would already have been impossible for humans to travel south overland from Alaska 18,500 years ago.
Using new radiocarbon dating techniques, it was proved that an ice-free corridor allowed passage south from the Alaska-Siberia land bridge at least 11,400 years ago.
Studies of various other hunting-gathering populations showed convincingly that, once the glaciers allowed passage, humans could have migrated from Alaska to Colorado in about 20 years.
题目要求找新证据反驳结论： 人类不是距今至少18,000你那之前从北边迁徙过来的，而是比这个时间要更晚。
A charcoal距今至少11400年，那也有可能更早啊，而且距今11400还是11200没有多大区别，也不是新证据。
B 又发现其他的campsite，无关
C 电脑模拟结果，无关
D 至少距今11400年以前有一条corridor连接了南北。新证据，人类可以通过这一条corridor从北边过来
E 只要冰川允许通行，人来就会怎样，但是没讲冰川什么时候允许通行，也有可能早于18000年前。
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