Q30: GWD-11-Q41:
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.
OG39. Most archaeologists have held that people first reached the Americas less than 20,000 years ago by crossing a land bridge into North America. But recent discoveries of human shelters in South America dating from 32,000 years ago have led researchers to speculate that people arrived in South America first, after voyaging across the Pacific, and then spread northward.
Which of the following, if it were discovered, would be pertinent evidence against the speculation above?
A. A rock shelter near Pittsburgh, Pennsylvania, contains evidence of use by human beings 19,000 years ago.
B. Some North American sites of human habitation predate any sites found in South America.
C. The climate is warmer at the 32,000-year-old South American site than at the oldest known North American site.
D. The site in South America that was occupied 32,000 years ago was continuously occupied until 6,000 years ago.
E. The last Ice Age, between 11,500 and 20,000 years ago, considerably lowered worldwide sea levels.
-- by 会员 YPandada (2010/10/26 19:45:29)