It has been hypothesized

Answer choices

1. A

   Opposite: unlikely3% picked this

   If a meteorite is formed early in the solar system's history, it contains chemical elements that are unlikely to be found in gas

   The author is thinking that a meteorite from around the time of the early solar system would be likely (if not certain) to contain chemical elements (such as iron-60) that were present in the supernova.

   3%
2. B

   Out of Scope: other solar systems1% picked this

   Other solar systems are not formed from clouds of gas and dust

   This argument is only about the story of our solar system, so the author doesn't need to assume anything about what goes on elsewhere.

   1%
3. C

   Trap5% picked this

   Supernovas do not produce significant quantities of any form of iron

   Negation Doesn't Weaken Only Thing Mentioned ? Only Thing Tons of correct answers on Necessary Assumption are written in a ruling-out "not" style, so we can negate this and see if it weakens. Would it hurt the argument to say that, "Supernovas do produce significant quantities of other forms of iron as well"? No, that does nothing. The author's argument could also work by saying, "Supernovas also produce iron-45, but there's no iron-45 in meteorites either", but that's not any objection to the argument the author is making. This answer is doing the classic Necessary Assumption trap of acting like "since the argument only mentioned iron-60, they must be assuming that iron-60 is the only type of iron we care about". We can never assume that because an author chooses to say "Y is true of X" that he's assuming that X is the only thing / the most important thing for which Y is true.

   5%
4. D

   Out of Scope: late history2% picked this

   Researchers have found iron-60 in meteorites that were formed relatively late in the

   The author's argument has nothing to do with later in the solar system's history. She doesn't really care whether iron-60 meteorites were or weren't found later. She is simply saying, since they weren't found early, that proves that the solar system wasn't created from a supernova's debris.

   2%
5. E

   Correct89% picked this

   If there had been iron-60 present in the early history of the solar system, it would be found in meteorites formed early

   Why this is right

   This shows us the Linking move we predicted, but in contrapositive form (as most correct answers on Assumption like to do, in order to better "hide" its correctness). We knew that the argument fell short of establishing the contrapositive trigger that "iron-60 was not present in the early history of the solar system" because all it told us was "iron-60 wasn't found in meteorites in the early solar system". The author was assuming that link of, "If we didn't find it meteorites, then it wasn't in the early solar system". And by contrapositive, "If it was in the early solar system, then we would find it in meteorites." Generally, it's unwise to negate conditional answers, but if we're negating (if X, then Y), we're getting "it's possible that X is true and Y isn't". So the negation here is, "It's possible that there was iron-60 in the early solar system, but not iron-60 in meteorites."

   Skill tested: Necessary Assumption · how this choice captures the argument's function is the move to repeat next time.

   89%