The Ganzt civilization (Knewton CR)

[bvn]

The Ganzt civilization, one of the earliest farming civilizations to exist in South America, mysteriously disappeared sometime around 2500 BC. Archaeologists long believed that the Ganzt's sudden decline was caused by overhunting because fossil records suggest that several species of boar and deer upon which the Ganzt were dependent went extinct around that time. Recently, however, archaeologists have begun to reject that theory, believing instead that the Ganzt's decline was in fact due to a critical Amazon tributary drying up suddenly.

Which of the following, if recently discovered, would help account for the change in the accepted explanation of the disappearance of the Ganzt civilization?


(A) Written records explaining that while the Ganzt people did grow food, they also depended heavily on hunting forest animals for sustenance.

(B) Chemical analysis of Ganzt remains revealing that the civilization's diet consisted mostly of freshwater river fish such as rainbow trout and salmon.

(C) The discovery of the remains of a number of tribes that managed to survive around the Amazon river and its various tributaries until around the year 2500 BC.

(D) Artifacts proving that the Ganzt developed a primitive farming system that depended on rainfall rather than complex irrigation from the Amazon river.

(E) Evidence that the sudden climate shift that dried several small Amazon river tributaries around the year 2500 BC changed the humidity level of the South American continent.

[jaxis]

B for me

[bvn]

B for me

Please add your explanation

[jaxis]

Is B the OA?

[shovan85]

IMO B

(A) Written records explaining that while the Ganzt people did grow food, they also depended heavily on hunting forest animals for sustenance.

Bolsters former idea. So incorrect.

(B) Chemical analysis of Ganzt remains revealing that the civilization's diet consisted mostly of freshwater river fish such as rainbow trout and salmon.

A strong contender. As river dries out this is one possibility which stops the source of their diet.

(C) The discovery of the remains of a number of tribes that managed to survive around the Amazon river and its various tributaries until around the year 2500 BC.

They managed to survive around it but the usage of the River is not explicitly mentioned.

(D) Artifacts proving that the Ganzt developed a primitive farming system that depended on rainfall rather than complex irrigation from the Amazon river.

Seriously undermine the later idea.

(E) Evidence that the sudden climate shift that dried several small Amazon river tributaries around the year 2500 BC changed the humidity level of the South American continent.

Humidity level is not our concern.

[missionGMAT007]

The dependency is correctly reflected in B

[kt00381n]

was debating between B and C, went with B, whats the OA

[bvn]

from Knewton

This is really a strengthening question, as the answer choices are meant to affirm evidence supporting the newer theory. How could the loss of a tributary cause the decline of a civilization? Why is this a better theory than the one blaming the decline on the extinction of mammal species? The correct answer will provide new evidence explaining why the river theory has become more plausible than the mammal theory.

Choice B is correct. This choice suggests that the Ganzt people were dependent on the river for food. If the river suddenly dried up, it could lead to their decline; moreover, this choice implies that the extinction of boar and deer might not have had as detrimental an effect on the civilization as was once thought.

Answer choice A strengthens the original theory regarding the loss of mammal species the Ganzt used as a food source. This is incorrect, because our goal is to strengthen the new theory.

Answer choice C introduces an irrelevant topic and does nothing to support or weaken the theory in question. Our concern is not with "a number of tribes," but solely with the Ganzt.

Answer choice D would be correct if the terms "rainfall" and "the Amazon river" were exchanged. As it is, the sentence explicitly states that the Ganzt were not dependent on the river, and thus that its loss would not have affected their farming.

Answer choice E states that the climate shift that dried Amazon river tributaries (such as the one in the theory stated above) had another effect as well; it changed the humidity level of the continent. This choice introduces a new factor, "humidity," which cannot bolster the causal connection between river-drying and the decline of the Ganzt. Even if it were the case that humidity contributed to the decline of the Ganzt, that would undermine, not strengthen, the theory that it was the drying of the river in and of itself that caused this decline.