LSAT 148 | Section 1 | Logical Reasoning: Q5

LR Question 5 Explanation

QUESTION TEXT: During its caterpillar stage, the leopard magpie moth…

QUESTION TYPE: Necessary Assumption

CONCLUSION: The leopard magpie moth faces extinction.

REASONING: The moth uses macrozamin from the natal grass cycad to make itself unappealing to predators. The Natal grass cycad may go extinct.

ANALYSIS: The argument is assuming that the leopard magpie moth has no other way of making itself unappealing to predators.

___________

1. CORRECT. If this isn’t true, then the moth might survive.
   Negation: There are other ways for the leopard magpie moth to make itself highly unpalatable to predators.
2. This strengthens the argument, but isn’t necessary.
   Negation: The leopard magpie moth does have the speed to escape from two of its predators. However, 98 other predators are fast enough to catch it.
3. This weakens the argument if true. If predators can’t tell the moths no longer have macrozamin, they may still avoid the moth.
   Negation: Predators will be able to tell that the moths no longer have macrozamin.
4. This strengthens the argument, but isn’t necessary.
   Negation: Leopard magpie moths are able to locate Natal grass cycads even if the plant is rare. But once the plant goes extinct, the moths will have no sources left and they will be hunted to extinction.
5. This doesn’t matter either way. “None” negates to “one or more”. If one out of 100 predators developed a resistance, how would that matter? 0 out of 100 isn’t much different from 1 out of 100. The single predator might be too slow to catch the moths routinely even though it has a tolerance.
   Negation: A single slow predator has developed a tolerance to macrozamin. That predator is also rare, and kills few moths.

Recap: The question begins with “During its caterpillar stage, the leopard magpie”. It is a Necessary Assumption question. To practice more Necessary Assumption questions, have a look at the LSAT Questions by Type page.