#2 - Among people who live to the age of 100 or more, a

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Complete Question Explanation

Strengthen, CE. The correct answer choice is (E)

Here we are told of a correlation between people who live past the age of 100 and those who have
led lives that we would generally consider to be unhealthy—drinking, smoking, eating poorly and
doing little exercise. Based on the fact that such behavior often leads to shorter lives, the author
concludes that those who have enjoyed long lives, despite unhealthy habits, probably have some kind
of genetic predisposition to living longer:

• Premise: A large portion of people who live to be 100 or more are known to have led
  unhealthy lives: drinking, smoking, eating poorly, and getting little exercise.
  
  Premise: Such unhealthy behavior often leads to a shortened lifespan.
  
  Conclusion: Those who live for exceptionally long periods must have been genetically
  predisposed to having longer lifespan.

The argument presented here is a causal one. The effect being considered is that of living past the
age of 100. The author believes that the cause must not be lifestyle, because a large proportion of
those with such long life spans have lifestyles that are known to be associated with shorter lives.
Instead, the author asserts that the likely cause is a genetic predisposition to a longer lifespan:

Cause Effect
Genes Long lifespan

The question stem requires that we find the answer choice that strengthens the author’s causal
assertion that those who live past 100, despite unhealthy lifestyle choices, probably have their genes
to thank for their long lives. The correct answer choice will probably either directly strengthen the
argument for a causal link between genetic makeup and long life, or perhaps rule out other possible
causes of the 100+ year lifespans of the people discussed.

Answer choice (A): This answer choice may provide some insight as to how one could eat fatty
foods and drink alcohol without suffering the detriment one might expect; while it may help to
explain how some individuals with such habits could still enjoy long lives, however, this choice does
not strengthen the link between genetics and long life.

Answer choice (B): First of all, the word “some” is quite vague—it could refer to one or more of the
individuals referenced in the stimulus. Further, the people described in this answer choice are not
members of the same group discussed in the stimulus. The author of the stimulus discusses those
engaged in drinking, smoking, eating poorly and getting little exercise. The fact that some people
with long lives do only some of these bad things does not strengthen the argument that genetics
likely plays a role in cases where people are long-lived despite very unhealthy lifestyles.

Answer choice (C): This answer choice is much like answer choice (B). The stimulus deals with
people who live long despite drinking, smoking, eating poorly and not exercising, whereas this
choice deals with a different population—the one or more people who make some good lifestyle choices and some bad ones. In any case, this choice does not strengthen the case for genetics playing
a role, as asserted by the author.

Answer choice (D): This choice deals with a population that is completely irrelevant to the subject
matter of the stimulus. We would probably expect that there would be cases of unhealthy people
dying before the age of 100, but this does not strengthen the author’s assertion that those with poor
lifestyles, but long lives, probably enjoy some genetic predisposition to longevity.

Answer choice (E): This is the correct answer choice, as it bolsters the argument that the long
lives are attributable to genetics: if the individuals discussed all had siblings who had similarly long
lifespans, then this would certainly strengthen the case for genetics’ having played some significant
role in their longevity.