According to a theory advanced by researcher Paul Martin, the wave of species extinctions that occurred in North America about 11,000 years ago, at the end of the Pleistocene era, can be directly attributed to the arrival of humans, i.e., the Paleoindians, who were ancestors of modern Native Americans. However, anthropologist Shepard Krech points out that large animal species vanished even in areas where there is no evidence to demonstrate that Paleoindians hunted them. Nor were extinctions confined to large animals: small animals, plants, and insects disappeared , presumably not all through human consumption. Krech also contradicts Martin's exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene. Still, Krech attributes secondary if not primary responsibility for the extinctions to the Paleoindians, arguing that humans have produced local extinctions elsewhere. But, according to historian Richard White, even the attribution of secondary responsibility may not be supported by the evidence. White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species, and Krech, though aware that the dates are controversial, does not challenge them; yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago. 1 Q1: Which of the following is true about Martin’s theory, as that theory is described in the passage? (A) It assumes that the Paleoindians were primarily dependent on hunting for survival. (B) It denies that the Pleistocene species extinctions were caused by climate change. (C) It uses as evidence the fact that humans have produced local extinctions in other situations. (D) It attempts to address the controversy over the date of human arrival in North America. (E) It admits the possibility that factors other than the arrival of humans played a role in the Pleistocene extinctions. 2 Q2: In the last sentence of the passage, the author refers to “ recent archaeological discoveries ” (lines 36-37) most probably in order to (A) refute White’s suggestion that neither Maritn nor Krech adequately account for Paleoindians’ contributions to the Pleistocene extinctions (B) cast doubt on the possibility that a more definitive theory regarding the causes of the Pleistocene extinctions may be forthcoming (C) suggest that Martin’s, Krech’s, and White’s theories regarding the Pleistocene extinctions are all open to question (D) call attention to the most controversial aspect of all the current theories regarding the Pleistocene extinctions (E) provide support for White’s questioning of both Martin’s and Krech’s positions regarding the role of Paleoindians in the Pleistocene extinctions 3 Q3: Which of the following, if true, would most weaken Krech’s objections to Martin’s theory? (A) Further studies showing that the climatic change that occurred at the end of the Pleistocene era was even more severe and widespread than was previously believed (B) New discoveries indicating that Paleoindians made use of the small animals, plants, and insects that became extinct (C) Additional evidence indicating that widespread climatic change occurred not only at the end of the Pleistocene era but also in previous and subsequent eras (D) Researchers’ discoveries that many more species became extinct in North America at the end of the Pleistocene era than was previously believed (E) New discoveries establishing that both the arrival of humans in North America and the wave of Pleistocene extinctions took place much earlier than 11,000 years ago 4 Q4: The passage suggests that Krech would be most likely to agree with a theory of the Pleistocene species extinctions that (A) included climate change as one of the causes of the extinctions (B) incorporated a revised date for human arrival in North America (C) eliminated the Paleoindians as a factor in the extinctions (D) identified a single cause for the extinctions (E) emphasized the role of hunting in causing most species extinctions 5 5. The passage mentions the extinction of species other than large animals (see highlighted text) Nor were extinctions confined to large animals: small animals, plants, and insects disappeared ] most probably in order to (A) suggest that the Paleoindians were responsible for more extinctions than Martin's theory assumes (B) provide support for the speculation that humans arrived in North America significantly earlier than the end of the Pleistocene era (C) point out the only area in which Martin, Krech, and White agree concerning the circumstances of the Pleistocene extinctions (D) cite additional evidence tending to support Krech's conclusions about the role of humans in the Pleistocene extinctions (E) raise a question about the logical consistency of Krech's view of Martin's theory

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According to a theory advanced by researcher Paul Martin, the wave of

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10 Jul 2021, 11:54

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Question 1

SALAKSHYA

Hi, GMATNinja, generis, @VeritasKarishma,@mikemcgarry , request your insights on question 1 here.

according to paragraphs :
" According to a theory advanced by researcher Paul Martin, the wave of species extinctions that occurred in North America about 11,000 years ago, at the end of the Pleistocene era, can be directly attributed to the arrival of humans,"

can this mean that Paul Martin denies other reasons such as climate change. and what do we mean by primary reason and directly attributed as given in paragraphs, does these mean that they were the only reasons.

If something is the "primary reason" for an event, we can't say that it is the ONLY reason for that event. There could be other factors that contributed to a lesser extent.

Luckily, there is another piece of the passage that tells us exactly what Martin thought about climate change:

"Krech also contradicts Martin's exclusion of climatic change as an explanation [for the wave of species extinctions]..."

Here, we learn that Martin specifically excluded climatic change as an explanation. So, we know that Martin's theory "denies that the Pleistocene species extinctions were caused by climate change."

(B) is the correct answer to question 1.

I hope that helps!

Thanks a Lot. It does make the matter clear.

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Hi ThatDudeKnows

I got question 2 wrong because the usage of the word "yet" after the semi-colon threw me off. While I agree with the OA, my question is about the usage of the word "yet". If we pay attention to the sentence structure of the last sentence, it begins with "White observes XYZ " and then there is a 'yet' followed by a mention of archeological discoveries. Isn't "yet" used normally used to show contrast or limitations to a certain argument? While the OA makes the perfect logical sense, I am not sure the usage of 'yet' is warranted here.

What am I missing?

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Namangupta1997

For that last YET, for example, it might be helpful to think of it as "...THAT BEING SAID, recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago."

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Namangupta1997

Namangupta1997

I'm a fan that you're looking for transition and structure clue words, like "yet." That's a GREAT habit.

In this case, what if we re-write that long last sentence in either of the following ways...would either or both of these have led you to getting the question correct on your first pass? If so, add to your transition/structure word spotting the ability to notice the impact of punctuation!! You don't need to dig into the specific terms "compound sentences" and "complex sentences," but it's worthwhile to identify opportunities to break up GMAC's long sentences. Semicolons can almost always be replaced by period.

As written:
White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species, and Krech, though aware that the dates are controversial, does not challenge them; yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago.

Revision one:
White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species.~~, and~~ Krech, though aware that the dates are controversial, does not challenge them; yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago.

Revision two:
White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species~~, and~~. Krech, though aware that the dates are controversial, does not challenge them.~~; y~~Yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago.

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ThatDudeKnows

Namangupta1997

ThatDudeKnows

I read both the versions of the revised sentence multiple times. Unfortunately, I am not able to grasp how the nuances in punctuation affect the meaning in this case. I'll still give it a shot :-

Rev 1 : It seems like the sentence starting with "yet" is written to give support to White's interpretation of Krech's theory. Or, simply put, it seems like an attack on Krech's theory. Not sure if I am right.

Rev 2 : "Yet" is preceded by a full stop. It is a new sentence. I am not sure which idea to connect it to now. Is it relating to White's interpretation of both the theories, just Krech's theory or it is a general statement?

Both the revisions and the original sentence seem too close. Ofcourse, if we understand the meaning of the given archeological discoveries, we can arrive at the answer. My question, though, still remains.
'Yet' is proving to be a real thorn in my understanding of the sentence structure.

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21 Jul 2022, 19:42

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Namangupta1997

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Namangupta1997

Okay, if the structural cues are fuzzy, let's go back to the passage and focus on WHY that portion of the sentence might be there. Who would want or not want it to be included?

Martin: "wave of species extinctions...can be directly attributed to the arrival of humans"

Krech: Hang on, that's too strong, but I'm okay with saying humans had some impact.

White: You're both wrong. Martin depends on coinciding dates and Kretch ignores date-based controversy.

So, which of the three care(s) about what follows the "yet?" Who is supported? Whose theory is refuted by the new info? White likes it and the other two don't, which is what answer choice E offers.

I think you're well-served to continue keeping a keen watch for structure and transition words. This question might just serve as a reminder that, while they can be awesome clues, we can't lean so heavily on them that we aren't able to take a step back and look at the passage more holistically when there's ambiguity or uncertainty about a structure/transition.

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Anyone please explain question 3.

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rbaral

It looks like Q3 has been pretty heavily discussed in page 2 of this thread. Can you take a look and then let us know if you have follow-up questions?

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rbaral

Anyone please explain question 3.

Discussed here.

https://gmatclub.com/forum/according-to ... l#p2670458

Cheers

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For question 1 - A can't be inferred from the passage. Remember, there are no assumptions in inference - it's either black and white from the passage or deductions based on the facts in the passage. Maybe they were 90% vegetarians and were killing animals for sports or fur or whatever else. We don't know, so we can't say "primarily" for hunting.

B is okay as per the passage, though please don't generalize that exclusion means denial. While exclusion involves leaving out or not considering a particular factor, denial implies a more explicit rejection or refusal to accept a particular claim or idea.

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Question 3

anoushki

sonalchhajed2019

Hi,

For Question 3 I selected the choice C.

Additional evidence indicating that widespread climatic change occurred not only at the end of the Pleistocene era but also in previous and subsequent eras

The reason for the same was that may be climate change was not responsible. There were such changes in the past and then extinctions did not occur. So probably factors other than climate change were responsible and this I thought is a better contradiction as compared to B.

Please let me know if my reasoning is correct. And why is B a better answer as compared to C.

Thank You
Sonal

I had the same reasoning. Can any expert give their two cents on this?
Chiranjeevi GMATNinja

Quote:

Q3: Which of the following, if true, would most weaken Krech’s objections to Martin’s theory?

Let’s consider (C):

Quote:

(C) Additional evidence indicating that widespread climatic change occurred not only at the end of the Pleistocene era but also in previous and subsequent eras

All that (C) tells us is that widespread climate change occurred in previous and subsequent eras. Sure, the extinctions that took place at the end of the Pleistocene era did not take place in previous eras, but we don’t know whether similar species existed in similar conditions in those eras. It’s possible that the climate change at the end of the Pleistocene era was more severe or that the combination of climate change and the arrival of Paleoindians led to the extinction of many species. Krech simply argues that climate change took place and could bear at least some of the responsibility for the extinctions. Even with (C), this is still possible. So, (C) does not weaken Krech’s argument, and we can eliminate it.

And here’s (B):

Quote:

(B) New discoveries indicating that Paleoindians made use of the small animals, plants, and insects that became extinct

This directly contradicts Krech’s implied argument that the extinction of small animals, plants, and insects cannot be attributed to the arrival of Paleoindians. By showing how Paleoindians could, in fact, be responsible for the extinction of these species, (B) weakens Krech’s argument. So, (B) is correct.

I hope that helps!

Nor were extinctions confined to large animals: small animals, plants, and insects disappeared, presumably not all through human consumption.

So, even Krech agrees that small animals population might have decreased due to human consumption. But humans may not be responsible for complete disappearance.
And option choice B says that humans are completely responsible for disappearance for small animals. Hence, option choice B weakens?

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nikitathegreat

Nor were extinctions confined to large animals: small animals, plants, and insects disappeared, presumably not all through human consumption.

So, even Krech agrees that small animals population might have decreased due to human consumption. But humans may not be responsible for complete disappearance.

And option choice B says that humans are completely responsible for disappearance for small animals. Hence, option choice B weakens?

Yes, Krech would agree that human consumption may have contributed somewhat to the disappearance of the small animals, plants, and insects, but the "presumably not all through human consumption" part seems to go against Martin's theory.

In Q3, choice (B) indicates that the Paleoindians made use of the small animals, plants, and insects that became extinct. So even if the Paleoindians' consumption of those things was minimal, the Paleoindians' use of those things could have contributed significantly to their extinction.

(B) does not say that humans are COMPLETELY responsible for the disappearance of those things; regardless, it's enough to weaken Krech’s objections to Martin’s theory.

I hope that helps!

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Got all five correct in 15 minutes. Not sure the timing is okay.

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Hi, about the first question, the passage says it excludes the climate change aspect but (B) in Q1 uses the word "denies" for the same. I thought there could be other reasons for the exclusion and didn't want to jump to the conclusion that exclusion means denial.

So I marked D instead.

What's wrong with my approach?

Bunuel KarishmaB

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We are given:
Krech also contradicts Martin's exclusion of climatic change as an explanation by asserting that widespread climatic change did indeed occur at the end of the Pleistocene.

We are given that Krech "contradicts" Martin by saying that climactic change could have played a role. Hence, Martin believed that climate did not play a role.
When Martin says A is responsible for B, he is pretty much saying C and D are not responsible. Else he would say A is partly responsible for B. When you exclude a possible cause in your explanation, you are saying that it is not the cause.

Hence, I don't see problem in question 1.

And (D) is certainly not correct. Look at the last line:
White observes that Martin's thesis depends on coinciding dates for the arrival of humans and the decline of large animal species, and Krech, though aware that the dates are controversial, does not challenge them; yet recent archaeological discoveries are providing evidence that the date of human arrival was much earlier than 11,000 years ago.

Martin's thesis depends on coinciding dates. He does not attempt to address the controversy or perhaps does not even know that it is controversial. They say that Krech is aware but doesn't challenge. All in all, (D) is certainly out. So (B) makes the most sense.

Answer (B)

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Hi experts KarishmaB GMATNinja MartyMurray DmitryFarber

In question-3, can we reject option C directly on the basis of following reasoning?
Martin doesn't even consider "climate change" so option C can't be an objection by Krech.

Krech only objects to Martin only in the context of humans hunting large animals by saying "....large animal species vanished even in areas where there is no evidence to demonstrate that Paleoindians hunted them. Nor were extinctions confined to large animals: small animals, plants, and insects disappeared, presumably not all through human consumption.", hence, option B is the correct answer.

Is the above reasoning correct to reject option C?

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Not necessarily, no. The passage tells us that Krech "contradicts Martin's exclusion of climatic change." This implies that Martin actively dismissed the idea of climate change as a cause of extinctions. Therefore, if an answer could show that Krech was wrong to consider climate change as a factor, it would weaken his objection to Martin.

If B made it seem less likely that climate change occurred during the key period, then it would weaken. However, it just says that climate changed happened before and after that period, too. This doesn't mean it wasn't a factor. Continuing climate change might well cause extinctions at a critical point, especially since it is a long-term phenomenon, not a quick event like an asteroid strike. B doesn't give us any reason to question Krech's belief that climate change may have played a role in the extinctions.

agrasan