题目信息
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?
A:Using new radiocarbon dating techniques, it was determined that the charcoal from the Colorado site was at least 11,400 years old.
B:Another campsite was found in New Mexico with remains dated at 16,000 years old.
C: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.
D: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.
E: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.
参考答案及共享解析
共享解析来源为网络权威资源、GMAT高分考生等； 如有疑问，欢迎在评论区提问与讨论
本题耗时：
已选答案：
正确答案：
D: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.
木炭是11200年前的（即11200年前有人类活动），而在11000和18000年前之间，冰川阻止人类迁到北美。所以人类是在18000年前到达的。
思路：在11000和18000之间，人类无法通过其它途径到达北美
A：木炭存在的时间长短，跟人类是否早于18000年进入，无关
B：与1同理，发现另外16000前的遗址，不能证明是否18000年前进入，不对
C：18500前不能进入，跟18000有500差距，不对
D：11400前，有通道让人类迁徙，正确
E：证明得出人类要20年迁徙时间，无关
加入收藏
在线答疑
题目来源
GWD
