PowerScore Weaken Problem #5

lyly85777

PowerScore Chapter 6 Weaken Question Problem Set #5
各位牛牛们来帮我理解一下这题吧在此谢过！[img]https://ci5.googleusercontent.com/proxy/x2UTgpsmTwuAlyld8QlmfwQM_OoREFYLPVu2tDGuo-l-NyAR4kdhb75P5el6m1MFtEj8Eq1k2WV8LDvjTPDxvLnexcKPZDq4jrW-r6tTQVCwAoFogMLFB6pmOA=s0-d-e1-ft#http://forum.chasedream.com/stat ... fault/handshake.gif[/img]
Archeologist: A skeleton of a North American mastodon that became extinct at the peak of the Ice Age was recently discovered. It contains a human-made projectiledissimilar to any found in that part of Eurasia closest to North America. Thus, since Eurasians did not settle in North America until shortly before the peak of the Ice Age, the first Eurasian settlers in North America probably came from a more distant part of Eurasia.Which one of the following, if true, most seriously weakens the archaeologist’s argument?
A. The projectile found in the mastodon does not resemble any that were used in Eurasia before or during the Ice Age
B. The people who occupied the Eurasian area closest to North America remained nomadic throughout the Ice Age
C. The skeleton of a bear from the same place and time as the mastodon skeleton contains a similar projectile
D. Other North American artifacts from the peak of the Ice Age are similar to ones from the same time found in more distant parts of Eurasia
E. Climatic conditions in North America just before the Ice Age were more conductive to human habitation than were those in the part of Eurasia closest to North America at that time.

我有点不理解为什么题目的意思。是说这个projectile不是part of Eurasia closest to North America的，那为什么说the author has assumed that the projectile is of Eurasian origin？所以这题的意思是虽然是在Eurasia但并不是靠近North America的地方?
另外为什么B选项不对呢？如果是remained nomadic也可以说他们是从更远的地方来的不是吗?