1. Which of the following does the author use to support the claim that humans crossed the Bering Land Bridge from Asia to North America?
A. The presence of the remains of now-extinct animals on both sides of the Bering Land Bridge - Incorrect. Nothing suggests that the animals are now-extinct.
B. Widely held theories describing early human migratory habits - Incorrect. Widely held theories are not discussed.
C. Recent discoveries of plant species that are known to have formed the basis of the diets of early humans- Incorrect. We don't know whether the plant species formed basis of human diet.
D. Archaeologists' uncovering of man-made tools on the Alaskan side of the Bering Land Bridge - Incorrect. Author never uses this to support the claim that humans crossed the bridge.
E. The clear presence of animal life during the years when Beringia was still above water -
Correct. This is stated by author. The presence of fish and bird fossils points to the possibility that Beringia could have supported human communities. This support the claim that humans crossed the bridge.2. It can be inferred from the second paragraph of the passage that the migration across the Bering Land Bridge did not take place five thousand years ago because
A. the melting of glaciers and continental ice sheets would have flooded the bridge, making it impassable - Correct. 5,000 years ago, the two continents were separated as major continental ice sheets and other glaciers melted and caused the sea level to rise again. This suggests that migration did not take place 5,000 years ago.
B. the Wisconsin glaciation period lasted from thirty thousand to ten thousand years ago - Incorrect. This could mean that the glaciers melted after this period. This gives a reason why migration could have taken place 5,000 years ago
C. by then, most sources of vegetation that supported animals would have been destroyed - Does not explain why migration did not take place.
D. the two continents, Asia and North! America, would have been separated due to continental drift - Continental drift is not mentioned.
E. by that time, mammoths, mastodons, and woolly rhinoceros had become extinct - Does not explain why migration did not take place.
3. The author's argument in the second paragraph would be most supported by the discovery of
We need an answer choice which shows that humans and animals both co-existed at that point in time. Only option B gives this explanation.
A. a 20,000-year-old, undersized mammoth skeleton on the Kamchatka Peninsula
B. 18,000-year-old cave drawings depicting humans and animals near the Mackenzie River
C. fossilized vegetation at Cape Olyutorsky that may have been part of the mammoth's diet
D. a 35,000-year-old reindeer skeleton near the Kolyma River
E. similar 20,000-year-old human skeletons on Unalaska Island and at Cape Olyutorsky
4. The passage is primarily concerned with
A. offering a thesis then providing supporting data - Correct. Thesis - Emergence of Bering Bridge. Supporting Data - Users of bridge, glacial activity, whether bridge supported life etc.
B. arguing against a traditional interpretation of a series of geological facts - Incorrect. does not argue. passage tone is neutral.
C. discussing the history of human migration - Incorrect. This is not the main concern of the passage. History of human migration is discussed very briefly.
D. presenting several possible scenarios for a series of historical events - Incorrect. No series of historical events is discussed.
E. critiquing the natural history of man - Incorrect. does not critique anything. passage tone is neutral.
5. It can be inferred from the passage that before the Quaternary period
The passage says that bridge emerged during quartenary period following a drop in sea level. From this we can infer that bridge was covered in water/ice before quartenary period. We can infer option C only.
A. animals may have crossed the Bering Land Bridge at many different intervals
B. animals only crossed the Bering Land Bridge during the last phase of the Wisconsin glaciation
C. Siberia was covered in continental ice sheets
D. humans did not penetrate North America
E. the plant life on Beringia had evolved sufficiently to support only grazing animals