It has been hypothesized that our solar system was formed from a cloud

Question

It has been hypothesized that our solar system was formed from a cloud of gas and dust produced by a supernova- an especially powerful explosion of a star. Supernovas produce the isotope iron-60, so if this hypothesis were correct, then iron-60 would have been present in the early history of the solar system. But researchers have found no iron-60 in meteorites that formed early in the solar system's history, thereby disproving the hypothesis.

Which one of the following is an assumption required by the argument?

(A) If a meteorite is formed early in the solar system's history, it contains chemical elements that are unlikely to be found in gas and dust produced by a supernova.
(B) Other solar systems are not formed from clouds of gas and dust produced by supennovas.
(C) Supernovas do not produce significant quantities of any form of iron other than iron-60.
(D) Researchers have found iron-60 in meteorites that were fanned relatively late in the solar system's history.
(E) If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early in the solar system's history.

LSAT

saswata4s · Answer

Hypothesis: Supernovas produce the isotope iron-60.

If this hypothesis were correct, then iron-60 would have been present in the early history of the solar system. 
But researchers have found no iron-60 in meteorites that formed early in the solar system's history and disproved the hypothesis.

Unstated assumption by researchers: If there was iron-60 present in the early days, it did not disintegrate over time.

Ans E.

Srid · Answer

Can anyone explain why c is not answer

Su1206 · Answer

This is an assumption question. Thus, we need to find an answer that  'Author believes to be true'.  It's ok if that is not true in real world; If author shall believe in it, it is an assumption.

(C) Supernovas do not produce significant quantities of any form of iron other than iron-60. - Author need not believe this to be true. It can be true that Supernovas do produce significant quantities of other forms of Iron, but, if iron-60 exists in meteors, it is sufficient to prove the hypothesis.

So, C is not necessary assumption.

Lets take a look at E : 
 (E) If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early in the solar system's history. -  For author to believe his reasoning to be true, he needs to believe in this statement.   
   By negating E, we weaken the argument.

Hope this helps.

If you like my explanation, do upvote. It motivates me. 
  Su!

napolean92728 · Answer

The  correct answer is (E)  If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early in the solar system's history.

Reasoning:
 In the argument, the hypothesis is that the solar system was formed from a cloud of gas and dust produced by a supernova, which would have included iron-60. The researchers have found no iron-60 in meteorites that formed early in the solar system's history, and the conclusion is that this disproves the hypothesis.
For this argument to hold, an important assumption must be that if iron-60 were indeed present in the early history of the solar system, it would have been incorporated into meteorites formed during that early period. This is exactly what answer (E) suggests — that the absence of iron-60 in early meteorites indicates its absence in the early solar system. If iron-60 had been present, it would have been found in these meteorites.

Why the other options are wrong:
(A)  If a meteorite is formed early in the solar system's history, it contains chemical elements that are unlikely to be found in gas and dust produced by a supernova.
This statement is unrelated to the argument. The argument is not about whether the elements in the meteorite could be found in the supernova's gas and dust, but about whether iron-60 should have been present if the supernova hypothesis is true.

(B)  Other solar systems are not formed from clouds of gas and dust produced by supernovas.
This is not an assumption required by the argument. The argument is focused on our own solar system, not others. It doesn’t rely on what happens in other solar systems.

(C)  Supernovas do not produce significant quantities of any form of iron other than iron-60.
This is irrelevant because the argument doesn't require us to rule out the production of other forms of iron. It only focuses on whether iron-60 was present in the early solar system, not on the total quantity or forms of iron produced by supernovas.

(D)  Researchers have found iron-60 in meteorites that were formed relatively late in the solar system's history.
This is not relevant to the argument. The researchers are concerned with the absence of iron-60 in meteorites that formed early in the solar system’s history, and this answer choice would not address that absence.

sintlaborum · Answer

How would negating E look like, would it be like this?

E.) If there had been iron-60 present in the early history of the solar system, it would not be found in meteorites formed early in the solar system's history.

E.) If there had not been iron-60 present in the early history of the solar system, it would not be found in meteorites formed early in the solar system's history.

guddo · Answer

The argument concludes that the solar system did not form from a supernova cloud because iron-60 is absent in early meteorites. This relies on the assumption that if iron-60 had been present early, it would have been preserved and detectable in those meteorites. If iron-60 could have been present but not found in meteorites (due to decay, distribution issues, or detection limits), the absence wouldn't disprove the hypothesis.

Option E states this necessary link explicitly: "If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early in the solar system's history." Without this assumption, the evidence doesn't support the conclusion.

Other options are not required:
- A discusses unrelated elements.
- B concerns other solar systems, not ours.
- C is about other iron forms, not necessary for the iron-60 focus.
- D is about late meteorites, irrelevant to early history.

Thus,  E is the required assumption .

guddo · Answer

I think, the proper negation of E is: Iron‐60  could have been present  early  and yet not be found  in early meteorites.

Your first try only reverses the consequence, and your second changes the “if” clause. Neither is the true negation.

If this negation is true, then  not finding iron‐60 doesn’t disprove the hypothesis , so the argument needs E to hold.

It has been hypothesized that our solar system was formed from a cloud

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GMAT Critical Reasoning (CR) Questions

It has been hypothesized that our solar system was formed from a cloud

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