PrepTest 145, Section 2, Question 5

What we’re looking for

Working the answers

• A
  Correct

  The historical events play the role of genes: they influence something else and cannot change. Historians' understanding plays the role of personality: it is related to that fixed thing, so the argument claims it cannot change either.

  But the events aren't the only thing that affects our understanding. Historians could acquire new evidence or look at familiar events through a different cultural perspective. Current events might also lead them to reconsider what past events meant. The war itself can stay unchanged while our understanding develops, just as unchanged genes needn't freeze a person's personality. This matches both the structure and the unsupported conclusion.

• B

  Government actions influence market forces, much as genes influence personality. But the next step is different: government policy changes, so the economy could change. The original says an influence stays fixed and therefore its associated result must stay fixed. B neither holds the influence fixed nor rules out change in the result. Its modest claim about a possible effect doesn't make our mistake.

• C

  This proposes changing a cause to prevent its effect. Genes can cause certain diseases, so manipulating those genes might prevent those diseases. It doesn't say the genes are unchanging and therefore the diseases must remain unchanged. Sharing the topic of genetics doesn't give it the required structure.

• D

  This moves from a benefit of long-term exercise to a smaller benefit of short-term exercise. Perhaps some benefits require a minimum period and don't appear at all in the shorter time. That would be a problem about how duration affects the result. Our argument instead assumes a result cannot change because one influence on it doesn't change. D never gives us that fixed influence.

• E

  We are told hormone levels control temperature, but not exactly how. High temperature doesn't automatically establish high hormone levels; the relationship could work differently, and other influences might matter too. That reasoning is questionable, but it works backward from a high temperature to a claim about the hormone levels. It doesn't start with unchanging hormones and conclude that temperature cannot change. That's the pattern we need.