LSAT 135 | Section 2 | Logical Reasoning: Q19

LR Question 19 Explanation

QUESTION TEXT: One theory to explain the sudden extinction of all dinosaurs …

QUESTION TYPE: Weaken

CONCLUSION: Dinosaurs may have gone extinct because they overdosed on poisonous angiosperms.

REASONING: Angiosperms appeared around the time dinosaurs went extinct. They contain potentially lethal psychoactive poisons. Mammals can avoid or detoxify them, but dinosaurs couldn’t.

ANALYSIS: The theory says dinosaurs ate these poisonous plants, overdosed, and died.

The strongest evidence comes from the fact that many dinosaur fossils are found in strange, contorted positions.

So the support is basically: Contorted fossils look like overdose deaths.

To weaken the theory, attack that support.

If lots of fossils from animals that were not killed by this dinosaur-specific overdose problem are also found in contorted positions, then the contorted posture is not special evidence of angiosperm poisoning.

Maybe bodies naturally fossilize that way, or death throes often leave animals contorted, or geological pressure bends remains.

The point is: the weird fossil positions stop being strong evidence for this theory.

___________

1. CORRECT. This weakens the theory’s strongest support. Mammals could usually avoid or detoxify angiosperm poisons, so if their fossils are also often contorted, then contorted fossil posture probably isn’t good evidence of dinosaur drug overdoses.
2. If anything, this might help the theory because it could make dinosaurs more likely to eat angiosperms.
3. This also strengthens. It helps explain how even meat-eating dinosaurs could’ve been affected.
4. Irrelevant. The theory is specifically about angiosperms that do produce these alkaloids.
5. This doesn’t weaken the theory. It shows angiosperms can be dangerous even to animals with better defenses, which makes the theory more plausible.