PrepTest 109, Section 4, Question 20
It would be wrong to conclude that a(36 more words not shown)
The reasoning in which one(13 more words not shown)
- AWhen a person(31 more words not shown)
- BEven if a(43 more words not shown)
- CWhen a bee(41 more words not shown)
- DA female holly(45 more words not shown)
- EA person cannot(33 more words not shown)
Reading the argument
Finding the bacteria isn't enough. The passage tells us that an infection also requires the person to be physically run down. If we only know that the bacteria are present, we haven't established that other requirement.
This is a parallel question, so let's name the roles before looking at the choices. The outcome is an infection. The evidence is the presence of bacteria. The missing condition is a run-down host. The argument warns us against jumping from that one piece of evidence to the outcome when another condition is required. It doesn't say the two conditions together guarantee infection, and we don't need to add that claim.
What we’re looking for
I'd look for another argument that says, in effect, “You have one of the things this result needs, but you haven't shown that the other required thing is present.”
Working the answers
- A
This offers two alternative explanations for blurred vision: an eye defect or certain drugs. That is different from saying that both the bacteria and a run-down host are needed for an infection. A asks which cause produced an observed effect; the original asks whether one condition is enough to establish an outcome when another condition is also required.
- BCorrect
The blooming plant matches the infection, adequate sunlight matches the bacteria, and slightly alkaline soil matches the run-down host. Knowing that the lavender receives enough sunlight doesn't establish that it will bloom because a separate soil requirement remains unconfirmed.
Both arguments resist the same shortcut. Evidence of one required condition doesn't establish the result when another required condition may be missing. The different subject matter doesn't change that relationship.
- C
This questions whether cold caused a colony's death by pointing to the bees' defenses against cold. It doesn't identify two conditions needed for an outcome and warn that only one has been established. Its explanation concerns resistance to a proposed cause, which is a different reason for withholding the conclusion.
- D
This does identify a requirement: a female holly needs a nearby male plant to supply pollen. But its conclusion concerns quantity. More male plants don't necessarily mean more berries. The original doesn't ask whether more bacteria mean a more severe infection; it asks whether the infection can be inferred at all without establishing another condition.
- E
This is closer because it also says that a piece of evidence is inadequate. But one unusually high reading doesn't establish a persistent pattern of high blood pressure. The issue is whether a single exceptional measurement supports the diagnosis defined by that ongoing pattern.
The original instead grants the presence of the bacteria and identifies a separate condition the host must meet. B reproduces that two-condition relationship directly: sunlight is one requirement, and the soil is another.
More Parallel Reasoning questions
Learn the LSAT our way
Our platform drills Parallel Reasoning questions at your level and adjusts as you improve.