7. People who live unusually long tend to have been lean young adults who went on to gain approximately one pound every year, so lean young adults can improve their chances of living a long life by gaining about a pound every year.
A flaw in the argument above is that it
(A) gives reasons for the truth of its conclusion that presuppose the truth of that conclusion
(B) proceeds as though a condition that by itself is enough to guarantee a certain result must always be present for that result to be achieved
(C) assumes without proof that two phenomena that occur together share an underlying cause
(D) concludes that one phenomenon is the cause of another when at most what has been established is an association between them
(E) fails to recognize that a tendency widely shared by a subgroup within a given population will not necessarily be widely shared by that population as a whole
A - lean young adults. B - people who live long. C - adults who gained one pound every year.
Premise: B tend to
have been (usually are) A who became C. B=A+C
Conclusion: A can
become B if
they become C too. A-> B, if A+C
A. reasons for the truth of conclusion (premise) presupposes (requires) the truth of conclusion. No, premise does not require the conclusion to be true. Rather, the conclusion is clearly derived from the premise.
B. there is no guarantee in the argument anywhere. 'Tends to' does not indicate a guarantee.
C. Proof is provided. Also, it is unclear which two phenomena occur together and which one is the cause? A and B do not occur together. There is a 'if' relationship between A and B which makes them sequential.
. Concludes that combination of A and C causes B, whereas 'tends to' in the premise indicates only a weak association. So does 'can improve' in conclusion.
E. The conclusion restricts itself to lean people. Population as a whole is not referred to anywhere in the argument.