Archeologists have discovered three sites showing conclusive evidence

Can someone explain why E is wrong and A is right ?

According to the official solution, B and E are strengtheners.

experts, Pls help me, what is the conclusion of the argument? It is because there is no key transition word.
"These sites clearly were founded by Homo erectus," -> how can A be the assumption if the information in A has been mentioned?
Furthermore, I am not sure how Homo erectus is related to the conclusion that "no reason to attribute mastery of fire to Homo ergaster". How?

Here is the OE from Magoosh.

Remains of prehistoric fire were found in Tanzania. The author says that Homo erectus made these fires, and that there’s no reason to assume Homo ergaster did. What is a necessary assumption?

The credited answer is choice (A). Homo erectus had to be as far south as Tanzania — if they were not, there would be no way they could have made those fires there, which would seem to indicate that Homo ergaster made them after all. Negating this statement devastates the argument, which is a confirmation that we have an assumption.

Whatever might have caused Homo erectus to master fire doesn’t clarify who made those fires in Tanzania: Homo erectus or Homo ergaster? Choice (B) is not correct.

Suppose Homo ergaster would have derived as much benefit from the master of fire as did the Homo erectus, or even more benefit. That fact, by itself, would imply nothing about which one of these species created those fires in Tanzania. Denying this doesn’t change the validity of the argument. Choice (C) is not correct.

Choice (D) is intriguing, because it may be true. Both Homo erectus and Homo ergaster evolved from Homo habilis, so it’s quite likely that the Homo habilis was the sole source of cultural knowledge for either of these species. BUT, we know that Homo erectus, presumably without the benefit of cultural knowledge about fire, was able to master fire. If Homo erectus did that, why couldn’t Homo ergaster? In other words, the limits of the cultural knowledge inherited does not necessarily set limits on what these human species could achieve. Therefore, we can draw no conclusion with respect to this argument. Choice (D) is not correct.

If Choice (E) were true, it would support the argument, but a supporting statement is not necessarily an assumption. We have to use the Negation Test. Suppose Homo ergaster was all over in Tanzania, before & during & after the time that those fires were created. Would that prove Homo ergaster started those fires? Not necessarily. It could still be true that both Homo ergaster and Homo erectus occupied that region, that only the latter had mastered fire, and therefore, that the later had to start those fires in Tanzania. Thus, we can deny choice and it doesn’t necessarily contradict the argument. Therefore, it is not an assumption. Choice (E) is not correct.

I agree. I didn't mark A as this was specified in argument that these sites were founded by Homo Erectus. If they were founded then they must have been occupied before migration of HE.

I understand that the point is if they were masters of fire or not at the time they founded the sites or before migration to asia. (The word immediately before migration) would still have made A correct. In its current state A looks essentially the same as info mentioned in argument.

generis I would appreciate your expert comment.

Posted from my mobile device

The answer A says, Homo erectus occupied territory as far south as Tanzania. But is it not a fact given in the question. Further to it the argument states Homo erectus moved towards north out of africa and into asia. Is this not evidence enough to prove homo erectus stayed in south as well. In fact A) has completely destroyed the crux of the passage itself. But argument says it needs a reason to show Homo ergaster could not be attributed to this. Now there is a reason from E) to believe homo ergaster attribution to fire.

When homo ergaster occupied the sites is irrelevant.We have to look a little closely to put this option under out of scope.

Neverthless a great question from an unofficial source..

Posted from my mobile device

The passage does not clearly differentiate between facts and subconclusions. So, it does seem to present as fact that Homo erectus occupied the sites mentioned, and at the same time could be interpreted as indicating that they did only as a subconclusion.

Your reasoning makes complete sense. The funny thing is that if you take as fact that Homo erectus occupied the sites, then maybe (E) is not an assumption upon which the argument depends, but of course, then (A) is not either.

Reviewing my EL - I understand where I went wrong.

I chose E incorrectly. The key is understanding the link between the evidence for me.

The argument is that we have no reason to attribute fire mastery to Ergaster since the evidence we have suggests that Erectus mastered the fire.
What evidence do we have to suggest this?
- Erectus founded the sites - so they were at the sites before other Ergaster
- Areas in Asia, where Erectus migrated, were found to contain similar sites
- Erectus migrated into Asia

Why E is incorrect - Even if Ergaster did occupy areas in Tanzania after the three sites the evidence is that Erectus was there at the sites first.
Negated: Ergaster occupied regions in Tanzania after the time of these three sites.
--> Negated statement actually strengthens the conclusion

A is the link between the evidence in Asia and the conclusion

A must be true for our conclusion and deduction to be correct.

If Erectus didn't occupy Tanzania, then we can't attribute these Asian sites, which led the archeologists to conclude that mastery of fire was learned, to Erectus, and therefore we cannot deduce that Ergaster did not potentially get to the Tanzanian sites first.

Hi everyone,

Context
Archeologists have discovered three sites showing conclusive evidence for the mastery of fire in Tanzania, from a period slightly after the time that Homo habilis was present in Africa.

Information:
These sites clearly were founded by Homo erectus, the descendent species of Homo habilis that migrated north, out of Africa and into Asia.

Evidence used to draw the conclusion:
Homo erectus was known to have mastered fire, from ample evidence at sites in Asia.

Conclusion:
There is no reason to attribute mastery of fire to Homo ergaster, the descendent species of Homo habilis that remained in Africa.


Which of the following is an assumption on which the argument depends?

Prethinking:
Now, we know that HErctus mastered the fire--> hence neither HA nor HErgaster mastered the fire

And that Tanzania is in Africa

And that HErectus moved from Africa to Asia

And that HErgaster is the evolution of HA and stayed in Africa.

The logical assumption is that HErectus lived in Tanzania before moving to Asia.

(A) Before their migration, Homo erectus occupied African territory as far south as Tanzania.
Correct as in line with pre-Thinking. Also try to negate the statement and the argument breaks.

(B) The strain of migration provided the selective pressure motivating Homo erectus‘ mastery of fire.
Irrelevant

(C) Homo ergaster would not have derived as much benefit from the mastery of fire as did Homo erectus.
Irrelevant

(D) Homo ergaster inherited all cultural knowledge from Homo habilis, a species that did not have mastery of fire.
Irrelevant

(E) Homo ergaster did not occupy regions as far south as Tanzania until well after the time of these three sites.
In order to cross this one out let's remember what an assumption is: It is a MUST BE TRUE STATEMENT. This choice is not because of well after. Hence incorrect

Ok. This is what i feel. Mastery of fire was occured in tanzania after Homo Habills which is confirmed by the evidence. This is a premise and we cannot doubt the fact

Homoerectus was descendant species of Homo Habills and Homoerectus was known to have mastered the fire when he migrated to Asia

Now in order to Conclusion to be true which is " There is no reason to attribute the mastery of fire to Homo Ergaster who remained in Africa , we must have an assumption that someone earlier than them or may be around the same time did that mastery of fire in Tanzania.

The only missing link would be that Homoerectus mastered the fire in Tanzania before migrating out of Africa to Asia. And to do that they must have occupied the territory of Tanzania before migration This would only be required assumption out of the choices.

Please let me know if that reasoning is correct

Hello Mike,
In this question, the conclusion is that "There is no reason to attribute mastery of fire to homo ergaster, the descendent species of Homo habilis that remained in Africa." What I have understood is that I have to assume something that will prove that Homo ergaster didn't master the fire. Now, option E states that "Homo ergaster did not occupy regions as far south as Tanzania Until well after .....". As per my understanding E means Homo ergaster were not in these sites earlier; therefore there is no chance to attribute the mastery of fire to Homo ergaster. Because mastery of fire happened in Tanzania where Homo ergaster was not even present before or during that happening. What I am missing here? mikemcgarry would be great to hear from you

Hi

Let me try to address your query.

Firstly, I believe you have identified the conclusion incorrectly. The conclusion must not only have a sense of finality about it, but it must also be based on other facts presented in the stimulus. If you assess the statement you have identified, there are no facts presented in the stimulus as to why mastery of fire must not be attributed to Homo Ergaster.

In my view, the correct conclusion of this stimulus must be: These sites clearly were founded by Homo Erectus.

This is derived from the following sentence: Homo Erectus was known to have mastered fire, from ample evidence at sites in Asia.

In other words, since evidence from Asia confirms that Homo Erectus had mastered fire, and the three sites in Tanzania showed conclusive evidence for the mastery of fire and dated from a period slightly after the time that Homo Habilis (a parent species of Homo Erectus) was present in Africa, the conclusion is drawn that these sites must have been founded by Homo Erectus. The statement on Homo Ergaster merely serves to further buttress this claim by ruling out an alternative explanation.

Now, clearly the assumption here is that Homo Erectus was in fact present in those sites, which is what is stated by option (A).

Hope this helps.

Hello CrackVerbalGMAT,
Many Thanks for your nice explanation. You are right, I was wrong in identifying conclusion. Thanks again!

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