Logical reasoning PrepTest 109 · Section 4 · Question 20

Incorrect. Very close! However, this argument brings up another sufficient explanation for a given symptom, not a separate necessary condition for a disease.

Correct. Argument or Facts:
Argument

Valid or Flawed:
Flawed

Question Type:
Parallel Reasoning

Stimulus Summary:
Strep infection requires the host to be run down
Conclusion - If the only evidence is Strep bacteria, you can't conclude a Strep infection

Answer Anticipation:
This argument starts with a conclusion, establishing that the presence of Strep bacteria by itself isn't sufficient to allow a conclusion to be drawn about someone having a Strep infection. Yes, the conclusion is about what can validly be concluded.

What's that based on? A premise establishing another factor (the host being run down) as being necessary ("unless") for a Strep infection.

So the argument establishes that one factor is necessary to reach a given conclusion, so it'd be wrong to reach that conclusion based on the presence of only another factor. Let's find an answer that follows that same (convoluted) pattern of reasoning.

Answer Explanation:
This answer establishes that it'd be wrong to reach a conclusion (that a plant will bloom) because of the presence of just one factor (6+ hours of sunlight) since there's a second necessary factor ("requires . . . slightly alkaline soil") for that outcome. This answer thus follows the same pattern of reasoning as the stimulus.

Key Takeaway:
In Parallel Reasoning questions, the more convoluted the argument, the more important it is to have a simplified and abstract version of it before you head to the answers.

Incorrect. This answer does conclude that a given conclusion can't be reached based on a single factor, but it doesn't bring up a second necessary factor needed to reach that conclusion.

Incorrect. This answer jumps from discussing whether a holly plant will produce berries to a conclusion about how many berries it'll produce, so there's a comparative element that isn't present in the stimulus.

Incorrect. This answer brings up a single factor but then discusses whether it's an outlier or chronic in determining a certain conclusion, so it takes a different form from the stimulus.