LSAT 2 | Section 4 | Logical Reasoning: Q16

LR Question 16 Explanation

QUESTION TEXT: Nuclear fusion is a process whereby the nuclei of atoms…

QUESTION TYPE: Weaken

CONCLUSION: Fusion had been achieved.

REASONING: The container had helium-4 gas. Fusion produces helium-4 gas.

ANALYSIS: We know that helium-4 is produced when fusion occurs. We don’t know if that is the only way to produce helium-4. If there are other reasons the helium-4 was present then the argument is considerably weakened.

Helium-4 is a necessary condition for fusion. It is not a sufficient condition.

___________

1. This is fine. We weren’t told that fusion would eliminate all other gases.
2. We are not told whether those by-products are present or not. Since they could be, the argument is not weakened.
3. CORRECT. This shatters the argument. Helium-4 is present in the air we breathe, and the amount in the chamber was not at all increased. That takes away the only argument that fusion had occurred.
4. This would tend to indicate that the helium-4 in the chamber was caused by the experiment. This strengthens the argument.
5. This would only weaken the argument if we had evidence that the chamber did not become warm. The stimulus doesn’t mention the temperature.

Recap: The question begins with “Nuclear fusion is a process whereby the nuclei of atoms”. It is a Weaken question. Learn more about LSAT Weaken questions in our guide to LSAT Logical Reasoning question types.