In Swartkans territory, archaeologists discovered charred bone fragmen

Question

In Swartkans territory, archaeologists discovered charred bone fragments dating back 1 million years. Analysis of the fragments, which came from a variety of animals, showed that they had been heated to temperatures no higher than those produced in experimental campfires made from branches of white stinkwood, the most common tree around Swartkans.

Which of the following, if true, would, together with the information above, provide the best basis for the claim that the charred bone fragments are evidence of the use of fire by early hominids?

(A) The white stinkwood tree is used for building material by the present-day inhabitants of Swartkans.

(B) Forest fires can heat wood to a range of temperatures that occur in campfires.

(C) The bone fragments were fitted together by the archaeologists to form the complete skeletons of several animals.

(D) Apart from the Swartkans discovery, there is reliable evidence that early hominids used fire as many as 500 thousand years ago.

(E) The bone fragments were found in several distinct layers of limestone that contained primitive cutting tools known to have been used by early hominids.

mikemcgarry · Accepted Answer

Dear getgyan , I am responding to your pm I agree this is not the best question --- in particular, it seems to requires some understanding of when "early hominids" lived or what constitutes "early hominids." It believe it's no coincidence that GMAC decided to drop this question in the move from OG12 to OG13. Nevertheless, the question has a clear answer. Here are the facts of the argument: We find these 1 million year old charred bone fragments. We don't know how they were charred. The argument tells us -- simple campfires could have done the charring. OK, that's good --- that means, the charring is at least consistent with the possibility of early hominids using fire, but it's certainly not ironclad proof the the charring was done by early hominids. By the end of the argument, we still don't know: how were the bone charred? Were they "cooked" by early hominids? Or were all those animals simply caught in a forest fire around the same time? We don't know what charred the bones, and we don't know whether humans were involved. Now, the question: " Which of the following, if true, would, together with the information above, provide the best basis for the claim that the charred bone fragments are evidence of the use of fire by early hominids ?" In other words, what would help us link the involvement of early human to the charring of the bones. Let's say for simplicity we have two possible hypotheses for how the bones were charred: (a) forest fire (b) use of fire by early hominids What further piece of evidence supports choosing (b) over (a)? Choices (A), (B), and (C) are ridiculous. Choice (D) is tempting --- if early hominids controlled fire 500,000 year ago, then at least it weakly suggests that maybe they could have controlled it 1M ya. Maybe . Evidence that early hominids had adopted any technology at Time #1 is strong evidence that they knew about this technology after Time #1, but it's very hard to make the argument that they definitely know about it long before Time #1. There's half a million years between 1M ya and 500K ya, and if mastery of fire were introduced any time in that half-million year span, that would mean that we couldn't deduce use of fire 1M ya from use of fire 500K ya. Choice (D) is, at best, weak, ambiguous, wishy-washy support for the argument. Choice (E) --- where we found the charred bone, we also found hominid tools --- aha! That is compelling evidence that the animals weren't just running wild and happened to be killed in a forest fire. It's compelling evidence that they were intentionally killed and cut up by early hominids, and therefore the charring of the bones happened when the animal remains were in the possession of the early hominids, presumably in some kind of cooking process. That strongly suggests the early hominids were able to use control and use fire. This is powerful support for interpretation (b) over interpretation (a). That's why (E) is a clear choice for the answer. Does all this make sense? Mike :-)

GMATNinja · Answer

We are trying to strengthen "the claim that the charred bone fragments  are evidence  of the use of fire by early hominids".

Pay close attention to the wording of the question stem, though! We are not just trying to show that early hominids used fire. We are trying to show that the charred bone fragments ARE EVIDENCE that early hominids used fire. That's a very subtle distinction, so make sure that is clear before you proceed to analyze the argument:

Archaeologists have discovered 1-million-year-old charred bone fragments in Swartkans territory. 
 The bone fragments came from a variety of animals. 
 The bone fragments "had been heated to temperatures  no higher than  those produced in experimental campfires made from branches of white stinkwood." Notice the use of "no higher than". That means that it is POSSIBLE that all of the bones were exposed to campfires made from white stinkwood branches. This does not PROVE that the bones were exposed to white stinkwood campfires, but it tells us that this is a possibility. 
 White stinkwood is "the most common tree around Swartkans."

So far, the evidence  could  support that campfires made from white stinkwood branches were used to cook animals in Swartkans one million years ago. We need an answer choice that supports the idea that the charred bone fragments are in fact evidence of the use of fire by early hominids. Again, we are not simply trying to show that early hominids  used  fire. We are trying to show that the million-year-old charred bone fragments  are evidence  that they used fire.

We don't care whether white stinkwood is or was used for building material. We are trying to show that white stinkwood campfires were used to cook animals in Swartkans a million years ago. Choice (A) is not relevant to this claim and can be eliminated.

If this is true, then the bones might have been charred by forest fires and not by campfires. This would actually weaken the argument, so eliminate (B).

Even if they could not fit the bones together, we would still know that we are dealing with charred animal bones. We are trying to figure out whether those animal bones were charred by campfires. Whether scientists can piece the bones back together has no bearing on the claim, so eliminate (C).

This one sounds great! We have evidence that early hominids used fire! That's what we were trying to show, right? Nope! We are trying to show that the million-year-old charred bone fragments  are evidence  that they used fire. If you didn't read the question stem carefully, you likely chose this tempting answer. But this does not tell us anything about whether those bones were charred by early hominids who built campfires. (D) only tells us that early hominids used fire up to 500 thousand years ago.  Maybe  early hominids used fire a million years ago, but choice (D) doesn't even support that claim. (D) must be eliminated.

All we have so far is a bunch of charred animal bones. Theoretically, they  could  have been charred by white stinkwood campfires. But who's to say that there were even any early hominids around to make such campfires? Right now we have no connection between the early hominids and the charred bones. All we know is that it is POSSIBLE that the bones were charred by white stinkwood campfires in Swartkans and thus that it is POSSIBLE that early hominids made those campfires in Swartkans. But it is still just as possible that the bones were charred some other way (i.e. forest fires). We don't have any strong evidence that early hominids were even around.

Choice (E) provides strong evidence that early hominids  were  around when the bones were charred. This does not PROVE that early hominids charred the bones with campfires, but it certainly strengthens this theory. Now what do we know: a million years ago in Swartkans we likely had early hominids AND charred animals bones AND trees that could have been used to make fires that charred those bones. Choice (E) supports the claim that the charred bones ARE evidence that early hominids used fire.

(E) is the best answer.

crisnas · Answer

The answer should be E.
Reasons:

A : Irrelavant to the topic i.e. use of fire by homonids
B : This will actually waken the argument 'coz this could be a potential reason for finding of the bones
C : Though it speaks about the various animals that were formed from bones, it doesn't say if the homonids really burnt these animals for consuming or what so ever
D : Though this states that the early homonids used fire, it doesnot in any way support that the charred bones are evidnece of use of fire by early homonids. Also, there is a dispute of time. While this statement refers to a period about 500,000 years ago, the question talks about a period 1 million years ago
E : Answer : The bone fragments are found in the same strata as that of the tools used by the homonids, meaning, there is all possibility of them being used by the homonids. Since the question does not talk about the homonids, we need to find that answer which relates the homonids to the charred bones.

Comments/ Views invited.
Krishna

getgyan · Answer

I got confused between D and E. Although "E" link the tools found with the bones to early hominids, it does not explain the two inherent drawbacks:
1) Early hominids does not exactly mean those who lived a million years ago
2) How is tool related to fire

Compared to E, D is more suitable but the OA does not agree.

getgyan · Answer

Hi Mike Thanks for the explanation. :-D

I have one more point of view What if the hominids along with their pet-animals died in the forest fire and then again in subsequent fires? E will make total sense in that respect too but it will not support the use of fire by the hominids. Thus the whole agenda boils down to prove that the charred bones were not burned in a forest fire. If we look at the stem, it states that " temperatures no higher than those produced in experimental campfires made from branches of white stinkwood" which implies that only the branches were burned whereas in a forest fire the whole tree(branch+stem) would burn. Also the temperature produced would be different in a forest fire because of the presence of other kinds of trees. Are my assumptions correct?

mikemcgarry · Answer

Dear Getgyan Part of the problem here is --- you are digging extra-deep into a question that is of questionable quality. Remember, this is one of the questions the OG decided to jettison. First of all, the idea of "pets" I believe is not 1M ya, but something more recent in human history. Even herding of animals was a relatively recent innovation, compared to the earlier hunting and gathering societies that existed during most of humanid evolution. More to the point, if humans & animals died together, they would have found charred human bones along with the charred animals bones --- that would be too important a finding to omit from the description. In other words, if they found charred human & animals bones, and said only "charred animals bones were found", that omission would constitute a level of pure deceit that you simply are not going to find in GMAT CR passages. Look at this statement " Analysis of the fragments ... showed that they had been heated to temperatures no higher than those produced in experimental campfires made from branches of white stinkwood ." What this says is: there is some ceiling temperature T, and the bones never got hotter than that. As it happens, T is also the temperature at which stinkwood campfires would burn. We know nothing else. We don't know if T is 800 K or 5000 K. We don't know whether stinkwood is the coolest burning or hottest burning wood in the forest. If there were a forest fire --- of course, a forest fire is a big thing, and it has a middle and an edge. How does the temperature at the middle compare to T? How does the temperature at the edge compare to T? Presumably, at any forest fire, there are some animals who die in the center, and their bones are just incinerated to ash, but there are also some on the periphery, maybe which die largely of asphyxiation, whose bones might just be charred but not incinerated. ----- In short, there is a lot we don't know about this statement and its potential implications. Other than establishing a plausible link between the charred bones and stinkwood campfires, we can't necessarily use it to prove or disprove anything else. Does all this make sense? Mike :-)

thangvietname · Answer

what is an assumption for this argument.?

pls help. 
the argument is

from chared bone---------> person use fire

what is assumption here? pls do not say more, pls, just tell me an assumption. nothing more.

after getting an assumption, I will continue to post a question

mikemcgarry · Answer

Dear thangvietnam , With all due respect, you are asking the wrong question. It's as if the question were "find the area of the circle", and you are asking how many vertices the shape has. What you are asking is a question that doesn't really make sense in context. You see, the prompt here is really just a set of evidence --- there's not really an "argument" in the prompt paragraph, just evidence. The conclusion is actually not in the prompt paragraph at all but in the question, and you need another piece of evidence (from among the answer choices) to establish this conclusion. You can't really even begin to identify an assumption until after you pick the correct answer, so trying to start the question by identifying an assumption is a strategy doomed to failure. Yes, I know that "identify the assumption" is an approach that works in a large number of CR, but on the GMAT, you can never afford to be a one-trick pony --- there's no "one size fits all" strategy that you can use on every single question. The GMAT will give you enough variety that you have to be flexible and resourceful in how you approach the problems. Does that make sense? Mike :-)

thangvietname · Answer

Dear Mike

you are correct that for many types of question, starting a question by identifying an assumption works well.

but for this type of question what do you do after you read the argument and the question? you have to know what you will find in the answer choices before you read and analyse answer choices.

what is your goal in reading the answer choices. ? pls detail your thinking process.

Thank you Mike.

mikemcgarry · Answer

Dear thangvietnam First of all, your statement " you have to know what you will find in the answer choices before you read and analyse answer choices " is FALSE in general. In the very specific cases of "find the assumption" or "strengthen/weaken the question", then yes, it's good to identify the assumption before you read the answer choices. For those three specific CR question types, your statement is true. In other CR question types, especially unusually ones like this, we have absolutely no way to anticipate how the answer choices will impact the logic of the argument, and hence there is no way to avoid reading and analyzing each answer choices. See this article about different CR question types: https://magoosh.com/gmat/2012/save-time- ... questions/ Remember, if you try to approach the GMAT CR with recipes and formulas, the GMAT will obliterate you. On the CR, the GMAT demands flexible critical reasoning. I have already written quite a bit about this argument in the posts above, so I am not going to go through a full analysis here. The procedures, briefly, would be --- for each answer choice, read the choice, and then evaluate whether this choice, in conjunction with the evidence in the prompt paragraph, supports the claim " that the charred bone fragments are evidence of the use of fire by early hominids ." Let me know if you have any specific questions about answer choices that I have not already discussed above. Mike

thangvietname · Answer

thank you Mike
I read the articles already.

there is no strategy for this type of argument. this is strengthen/weaken question but this question dose not require prethink an assumption.

what we do after we read/understand argurment and before we read/analyse the answer choices, for this type of question. ?

"look for what increase the belief that the 2 pieces of evidence are related"

is what we need to know before going to answer choices.

is that right?

mikemcgarry · Answer

Yes. You see, the GMAT excels at producing question that demand flexible logical reasoning. You absolutely cannot afford to get stuck in a rut, applying the same routine to each question. Instead, many GMAT CR questions demand something entirely new, analysis unlike that demanded by any previous question. This question is an example of such a question. It is not a "question type." It is an out-of-the-blue question all of its own, and you have to engage deeply with the logic of the situation itself. Many questions on the CR, both in the OG and on the real GMAT, will be just like this. Yes, there are a few "types", like "find the assumption", where you definitely can do some "pre-thinking" before you look at the answer choices. Nevertheless, do not get attached to that luxury. Many questions ask you to engage the logic-in-context of the situation, and there's no recipe/procedure/method that will save you from this deep and contextual logical reasoning. Here's a post that discusses this a little more. Formal Logic and GMAT CR Do you know the magazine entitled The Eco nomist ? I would highly recommend this magazine, both for the tremendous overview of world political and economic issues it provides, and for high level of language, rhetoric, and argument is maintains. See this post: Reading for the GMAT: The Economist If you read the argument in that magazine--you will be reading messy real world arguments, arguments that are inextricable bound to what is unique to each situation. You cannot use recipes or formulas to understand these arguments. You need to understand context itself. Reading The Ec onomist magazine would give you excellent preparation for the wild diversity of possible arguments in the GMAT CR. Think about it. The whole point of the CR section on the GMAT, the reason business schools consider this an important topic, is that in the business world you will face new situations and new arguments and new issues all the time. The folks who respond to a new situation or argument with formulaic methods will not get everything out of the situation that he could. By contrast, the person who recognizes the unique logic of each new context --- the person will be on the cutting edge, always poised to draw profit from each new challenge. Does all this make sense? Mike

teaserbae · Answer

AjiteshArun  
Can you please brief how does E provides additional evidence ?
It is just talking about cutting tools no link with the fire.
How does it support they used fire ?

AjiteshArun · Answer

All we know is that charred bone fragments were found, and that they had been heated to "campfire temperatures". Now suddenly we are asked to pick an option that helps show ("through" the bone fragments) that  early hominids  used fire. This is impossible without some additional information, as  there is currently no connection at all between the bone fragments and early hominids .

One way to establish the connection we need is to directly link the bone fragments to hominids. Another way is to introduce something that is common to both. So early hominids are "connected" to X, and X is "connected" to the bone fragments, and therefore there is a connection between hominids and the bone fragments. That's what option E does:

The bone fragments were found in several distinct layers of limestone that contained primitive cutting tools known to have been used by early hominids.

E tells us that the tools (a) are definitely "connected" to hominids, and (b) were found in the "same layers" as the bone fragments, which establishes a link between the tools and the bone fragments. Now we have a connection between hominids and the bone fragments.

It's important to remember that even if the connection that E provides is not particularly strong, it is still the best option out of the 5 that are given to us. Because the other options are irrelevant (or weaken the claim), we should look at E as the best of the 5 and mark it as the answer.

delmoneyy · Answer

Hi experts, I was wondering what they mean by early hominid

GMATNinja · Answer

Consider the following example: "Early symptoms of the disease include nausea and vomiting." In this case, "early" modifies symptoms and tells us that nausea and vomiting are among the  first  (or "earliest") symptoms of the disease.

So if, for example, hominids (a family of primates) have been around for about 20 million years, then  early  hominids would be the ones who were alive towards the beginning of that period. Notice that the precise definition of primates is not actually important here. The logic remains the same even if we replace "early hominids" with something more generic, such as "members of Group A".

Q: "Which of the following, if true, would, together with the information above, provide the best basis for the claim that the charred bone fragments are evidence of the use of fire by  ?"
A: (E) The bone fragments were found in several distinct layers of limestone that contained primitive cutting tools known to have been used by  .

I hope this helps!

Engineer1 · Answer

GMATNinja - I think we need an additional evidence. I still do not understand why E and not D is correct. E definitely provides a strong evidence that early hominids existed during the time period when charring of those occurred. But it does not still prove that hominids knew how to use fire. Whereas, D fills this gap. Could you please explain further?

KarishmaB, please help.

Thank you!

KarishmaB , please help.

Thank you!

KarishmaB · Answer

Engineer1 - Option (D) is plain wrong. Even if I were to change the 500 thousand to 1 million, it would still be wrong. Here is an important point - what is the conclusion of the argument? What do we have to strengthen? Conclusion: The charred bone fragments are evidence of the use of fire by early hominids We have to provide strength to this conclusion. The conclusion is not that early hominids used fire. We don't have to support that. We have to support that these charred bone fragments are evidence of the use of fire by early hominids. So we need something that ties these bone fragments to early hominids and fire. Option (D) ignores bone fragments and talks about other evidence. But our conclusion is that bone fragments are evidence. Hence (D) is incorrect. (E) The bone fragments were found in several distinct layers of limestone that contained primitive cutting tools known to have been used by early hominids. So looks like early hominid tools were found at around the same time and area to which the bone fragments belonged. This is re-assuring. They were around and using cutting tools. So they could have cut down trees to make campfires. Of course, it doesn't prove anything but it links all these variables together. Answer (E) Check out this video: https://youtu.be/Q5SG0ZZcHKA The most important step in strengthen/weaken is 'Identify the conclusion'

anirchat · Answer

A - Irrelevant.
B - Weakens
C - Already claimed in passage, so doesn't help.
D - There is a difference in time.
 E  - Strengthens.

In Swartkans territory, archaeologists discovered charred bone fragmen

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In Swartkans territory, archaeologists discovered charred bone fragmen

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