Logical Reasoning

PT104 · S4 · Q6 Monarch butterflies spend the winter hibernating

A free, expert breakdown of this official LSAT Logical Reasoning question.

Save & drill this skill — build targeted practice sets from questions like this one
Video walkthroughs — watch every question solved step by step
81 official LSATs — as questions, timed sections & full-length tests

Monarch butterflies spend the winter hibernating on trees in certain forests.

Conclusion

The tour groups are endangering the monarch population.

Evidence

The tour groups trample most of the small shrubs that are necessary to the survival of any monarch butterflies that fall off the trees.

Evaluate

Given how strong the word 'necessary' it is, it conveys that if not small shrubs → can't survive

If the tourists are destroying most of the small shrubs, is there any way to say that they're not endangering the monarch population?

We could say, But that's a pretty weak retort. If we're destroying most of the shrubs they need to survive, we're definitely endangering them, even if they're able to barely hang on with the remaining shrubs.

So what other wiggle room is there? There's actually a conditional that hasn't been triggered:

In other words, If a monarch falls off a tree, then the shrubs are necessary.

But what if they don't fall off trees? In that case, we have no idea if these shrubs are necessary at all.

Goal

We considered two possible objections - Are the remaining shrubs (the minority that weren't trampled) enough to comfortably support the monarchs, or is it endangering them to miss out on so many shrubs?

- Do monarchs actually fall off trees, or is this not a real problem we need to worry about?

Which one of the following would it be most useful to know in evaluating the argument?

The amount of forest land
Out of Scope
How much Other habitat exists for monarchs has nothing to do with whether or not tourists are endangering the monarch population in this habitat. Maybe could say, "The tourists aren't endangering the monarchs -- after all, there's a large amount of forest land suitable for monarchs that's not currently used by monarch", but that would be twisting the meaning of this conclusion. The conclusion isn't saying that the monarchs are now an endangered species with little available habitat. The evidence is saying that woodcutters are decreasing the available habitat, and that tour groups are undermining the ability of the monarchs to survive in the area where they are.
3% picked this
The amount of wood cut
Out of Scope
Sort of like (A), this is asking us to numerically quantity the threat of habitat loss from woodcutters. We don't need to be further convinced that woodcutters are encroaching on the habitat of monarchs. We accept the background evidence that woodcutters are a threat to the butterflies. We're only trying to evaluate whether local tour groups, walking through the butterflies' habitat, stomping on small shrubs, are also a threat to local populations of monarchs.
3% picked this
The amount of plant life
Out of Scope
Since we're trying to assess whether or not the tourists are endangering survival by trampling on necessary plant life, it's not really relevant whether the tourists are also trampling on plant life that doesn't matter to monarchs.
13% picked this
The proportion of the trees
Out of Scope
Just like (A) and (B), this is trying to quantify the threat of the woodcutters, when all we care about is assessing the threat of the of the tour groups. We wouldn't care if 13% of the woodcutters' business came from monarch forests vs. 47% vs. 84%. No matter what share of the woodcutters' business it represents, it still represents a threat to monarch habitat.
6% picked this
Correct
The proportion of hibernating monarch
Why this is right
If 90% of monarchs fall off trees, then they will need small shrubs to survive. Since tourists are trampling most of these shrubs, this would strengthen the idea that the tour groups are endangering the monarch population. Meanwhile, if only 5% of monarchs fall off trees, then 95% of the monarchs aren't worried about those small shrubs, so whatever the tour group may be doing to the shrubs would not be endangering the monarch population. This possible answer would weaken. If we find an answer choice where one possible answer to it strengthens and an opposite type of answer to it weakens, we've found our correct answer.
Skill tested: Evaluate · how this choice captures the argument's function is the move to repeat next time.
74% picked this

Continue the review in LSAT Lab

Save this question, watch the video walkthrough, and drill similar questions in your LSAT Lab account.

Save and practice this skill

LSAT Lab

Turn this review into a targeted study plan.

Save this question, drill more like it, watch the video walkthrough, and track your progress in your LSAT Lab account.

Start practicing free