Because all Polynesians, Micronesians, and many Melanesians speak Austronesian languages and grow crops derived from Southeast Asia, all these peoples most certainly derived from that region and not the New World or elsewhere. The undisputed pre-Columbian presence in Oceania (the great pacific regions of islands) of the sweet potato, which is a New World domesticate, has sometimes been used to support Heyerdahl's "American Indians in the Pacific" theories. However, this is one plant out of a long list of Southeast Asian domesticates. As Patrick Kirch, an American anthropologist, points out, rather than being brought by rafting South Americans, sweet potatoes might just have easily been brought back by returning Polynesian navigators who could have reached the west coast of South America.
Why does the author mention the views of “Patrick Kirch”?
To present evidence in support of Heyerdahl’s theory
To emphasize the familiarity of Pacific islanders with crops from many different regions of the world
To indicate that supposed evidence for Heyerdahl’s theory has an alternative explanation
To demonstrate that some of the same crops were cultivated in both South America and Oceania
Hi everyone, let’s solve this question. As it is phrased "why does the author mention," we know that this is a rhetorical purpose question. While 70 percent of rhetorical purpose questions are easy, as the answers are usually to illustrate a general idea mentioned earlier, 30 percent of rhetorical purpose questions can be quite tricky if you don’t understand the context where the highlighted item occurs. This rhetorical purpose question belongs to the challenging 30 percent. So, the question is why the author mentions the views of "Patrick Kirch." To answer this question, you need to understand how the paragraph is organized. We will read each sentence and understand its meaning clearly. This is the first sentence of the paragraph:
Because all Polynesians, Micronesians, and many Melanesians speak Austronesian languages and grow crops derived from Southeast Asia, all these peoples most certainly derived from that region and not the New World or elsewhere.
So, the sentence states that since all Polynesians speak Austronesian language and grow Southeast Asian crops, the Polynesian people must have come from Southeast Asia, not from the New World.
This is the second sentence:
The undisputed pre-Columbian presence in Oceania of the sweet potato, which is a New World domesticate, has sometimes been used to support Heyerdahl's "American Indians in the Pacific" theories.
The sentence says that the fact that sweet potatoes existed in Oceania during the pre-Columbian era is often used to support Heyerdahl’s theory. Why? Because sweet potatoes were originally from the New World. And what is Heyerdahl's theory? It is that American Indians (that is, New World inhabitants) came to the Pacific islands. So the implied idea, according to Heyerdahl’s theory, is that American Indians colonized Oceania and brought the sweet potatoes with them to Oceania.
Heyerdahl's theory: American Indians came to the Pacific islands and brought sweet potatoes.
This is the next sentence:"
However, this is one plant out of a long list of Southeast Asian domesticates.
However" signals a contrast to the previous idea, which is that sweet potato is one of the Southeast Asian domesticates as well. And then finally, we have the sentence with Patrick Kirch
As Patrick Kirch, an American anthropologist, points out, rather than being brought by rafting South Americans, sweet potatoes might just have easily been brought back by returning Polynesian navigators who could have reached the west coast of South America.
Patrick Kirch’s idea is that, instead of American Indians bringing sweet potatoes to Oceania, the sweet potatoes could have been brought back by Polynesians who reached South America and then sailed back. So Kirch provides a different theory that explains how sweet potatoes exist in Pacific islands. Heyerdahl's theory is that sweet potatoes in the Pacific islands come from American Indians. Kirch's alternative theory is that sweet potato could have been brought back by Polynesians, not by American Indians
With this understanding, let's consider the options:
Why does the author mention the views of “Patrick Kirch”?
To present evidence in support of Heyerdahl’s theory
A is the opposite. Kirch has a different theory for the existence of sweet potatoes in Oceania.
To emphasize the familiarity of Pacific islanders with crops from many different regions of the world
B is not relevant.
To indicate that supposed evidence for Heyerdahl’s theory has an alternative explanation
Sweet potatoes in the Pacific islands are used as evidence for Heyerdahl’s theory, but Kirch offers a different theory for the existence of sweet potatoes in the Pacific islands. So, C is consistent with our findings.
To demonstrate that some of the same crops were cultivated in both South America and Oceania
D is factually true; some of the same crops were cultivated in both South America and Oceania, namely sweet potatoes. However, Kirch’s point is that he can explain the existence of sweet potatoes in Oceania without resorting to American indians’ bringing them to Oceania.
So the answer is C.