LR Question 16 Explanation
QUESTION TEXT: In most of this forest, the expected outbreak of tree…
QUESTION TYPE: Complete the Argument
CONCLUSION: We should not stop the tree-eating tussock moths.
REASONING: Moths are helpful where lack of forest fires has left forests full of immature trees. (And this forest is full of immature trees)
ANALYSIS: On complete the argument questions, you have to think about the logic of the argument, and then think about how to add to that logic.
Most of the wrong answers here are things that are merely consistent with the argument. But we don’t just want something true. We want something that strengthens the argument. (This is an unusual question stem – most complete the argument questions ask for a conclusion, not a premise).
Here, the author is saying moths help when forests have too many immature trees. And they’re saying we should allow the moths in this forest. That must mean that this forest has too many immature trees.
___________
- CORRECT. The argument says moths are beneficial where forests are overcrowded with immature trees, and concludes they shouldn’t be stopped in most of this forest. This only makes sense if more than half the forest is overcrowded.
- This contradicts the logic of the argument. The author said that moths help when we have too many immature trees. The moths should be eating those trees, not the mature trees.
- This is just a fact that tells us what happens during forest fires, in general. It adds no information about the specific forest: we’re trying to decide whether to allow moths there, or not.
- So? We still have the option of countering the outbreak. This answer doesn’t tell us whether or not we should counter the outbreak.
- This answer is trying to make you think we can do nothing against the moths, but that’s not true. For example, perhaps we could stop 99.99999% of them, even if we don’t have a completely effective solution.
More Resources for Complete the Argument Questions
- Intro Course lesson: This intro course lesson covers Complete the Argument questions.
- Mastery Seminar lesson: This LR Mastery seminar lesson covers complete the argument questions.
Hi, really love these explanations but I thought I’d comment on this one. Thanks for providing them
If we are not stopping moths because of forest fire effects, then it is better for this argument if more of this effect exists. I do not believe this explanation accurately explains the nuance of “most”, which is the crux of this question. “In most” is what it begins with and talks about an effect of the forest without mentioning how much of the forest is affected.
It does not say ” The argument says moths are useful when a forest has too many immature trees”. Seems that this argument is talking about this forest only.
You might be right. The argument says “the moth is beneficial where” which is a general statement, and I took the claim about forest fires to refer to this and hence apply to forests generally. As in:
Where suppression of forest fires [in a forest] has left the forest crowded with trees –> i.e. this refers to spots within a forest that are crowded, but not the whole forest necessarily.
It is possible the claim only refers to this particular forest. In any event you’re right that the symmetry of most in the first sentence and “more than half” in A are important in making the answer correct. I’ll update this to address that point.
Note: This is an old comment but I wanted to clarify the point.