[問題]gwd-11-41

[訪客]

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.


BD決選,答案是D,B錯在哪???

[micht]

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?

這題難呀... ><! 好多數據很混淆

不過　我選(D)

Alaska ← Sibera (建橋 18000~11000年ago)
推得
Alaska ← Mexico 約11200 old (humans must have come to the Americas more than 18,000 years ago.)

可是我們要問∼真的嗎?

Weaken

B. Another campsite was found in New Mexico with remains dated at 16,000 years old. (不代表沒有另一個 18,000 古蹟∼也許有只是還未被挖掘出來)因此還是有可能18000以前到美州...

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

新的proved指出 Alaska ← Sibera 還有另一個方法 by free corridor 需要at least 11,400 years ago

那麼　Mexico也可以嘍? 不一定要採用bridge 所以不一定是 18000


我的理解如上
待有人加以確認..

[訪客]

這題的邏輯式子應該是這個樣子
18000~11000這段期間因為冰河阻擋不能由西伯利亞到阿拉斯加=>那些到美洲的人因該在18000年之前

D的選項直接把因否決掉,所以D是最佳選擇
B則如micht所說的不能完全確定這個是從西伯利亞到阿拉斯加,也可能是有人從南美洲到北美洲,ETS給New Mexcio似乎給你這樣的暗示

[CUGGYER]

請問那C呢

否定了結論: 18000年前 已經有人經由西伯利亞到阿拉斯加

因為他說即使是18500年 冰河已經阻礙人們通行

這個選項不是也能weak嗎?

[zuckzhc]

請問那C呢

否定了結論: 18000年前 已經有人經由西伯利亞到阿拉斯加

因為他說即使是18500年 冰河已經阻礙人們通行

這個選項不是也能weak嗎?

I think the point is "computer simulation". A computer simulation is not a soild evidence.

[maronchen1103]

請問那C呢

否定了結論: 18000年前 已經有人經由西伯利亞到阿拉斯加

因為他說即使是18500年 冰河已經阻礙人們通行

這個選項不是也能weak嗎?

因為18500年已經阻礙通行啦
C只是將不能通行的時間範圍延伸為18500~11000年
題目結論是more than 18000就來了
C支持結論阿....
18500~11000年期間都沒有人能來....所以11200年的Charcoal在超過18500年前就來了...支持more than 18000年

D說11400年前就有其他方可以過來了....Charcoal人可能就是那時來的
非18000年前來的....weaken

[juyu]

我的(B)(C)不選的看法有點不一樣,請大家參考
(B)不選的原因是:一個campsite是16000年以前的-->對照題目的,人在比18000年以前更久遠時就來了,也蠻合理的,所以不能反駁題目
(C)不選的原因是:..18500年以前不能來-->對照題目的,人在比18000年以前更久遠時就來了,也不衝突,所以不能反駁題目

[Lory]

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.


BD決選,答案是D,B錯在哪???

鍵定C物的時間
__________18,000_________11,200________11,000____Now
18,500 此乃題目認為冰河造成無
法通過的時期
(D)選項減弱該期間所提供
的證據，即直到11,400年
前，該冰河形成的通道，
可讓人通行。
(C )選項,根本是支持結論: 即早在18,000前，人就可通過passway來到南方

(B)是過度推論喔!!!雖然new mexico是在南方，但超出討論範圍

(A)分化重點，不在於釐定到底C物真正的鍵定時間是多久

(E)絕對irrelevant喔!!!很好刪

[hahadog]

推樓上的時間圖表
用年表畫一畫就清楚多了～
不然一堆數字晃來晃去的都暈了

[shoulo]

D說11400年前就有其他方可以過來了....Charcoal人可能就是那時來的
非18000年前來的....weaken

Charcoal 是木炭吧~~
好像不是一種人耶