PrepTest 139, Section 4, Question 23

What we’re looking for

Working the answers

• A

  This says transfer is easier from wild plants to domesticated ones than in the direction we care about. The botanist predicts a domesticated crop's pesticide resistance passing to wild relatives. Knowing the opposite direction is easier doesn't establish that this transfer will occur.

• B

  More domesticated radishes made the color change spread faster. That adds detail about the same trait in the same plant comparison. It doesn't connect flower color with pesticide resistance or show that other crop-and-weed relatives would behave similarly.

• C

  This makes radishes a questionable basis for the broader prediction. If they aren't representative in how easily traits transfer, their flower-color result may not tell us what will happen with other crop plants. That undermines the use of the example rather than strengthening it.

• D

  This distinguishes the observed flower color from the often genetically engineered resistance the botanist is discussing. It gives us no reason to think an engineered trait would transfer in the same way. We don't have to assume that engineered traits transfer differently, but the answer does nothing to close that possible gap.

• E
  Correct

  The observed color transfer is unusually difficult: harder than almost any other trait transfer between similarly related plant species. Yet it happened. That makes the example more persuasive as evidence that another trait could cross from a crop plant to a wild relative.

  This answers our concern that color might have been an especially easy case. The wording is “almost any,” so it doesn't guarantee that every possible trait will transfer or that resistance cannot be an exception. A strengthener doesn't need that guarantee. It gives us a substantial reason to be more confident in the botanist's prediction.