LSAT 118 | Section 4 | Logical Reasoning: Q11

LR Question 11 Explanation

QUESTION TEXT: Between 1976 and 1985, chemical wastes were dumped into …

QUESTION TYPE: Evaluate the Argument – EXCEPT

CONCLUSION: The chemicals caused the fin deformity in the bluefin cod.

REASONING: Chemicals were dumped into Cod Bay, which are known to cause genetic mutations.

ANALYSIS: The argument is:

Chemicals were dumped -> can cause mutations -> cod now have deformed fins -> therefore chemicals caused the deformities.

The problem is that there could be other explanations.

Maybe the fish in Cod Bay already had fin deformities before the dumping.

Maybe 3% of the bluefin cod population having deformities is normal.

Maybe it was caused by some natural disease or another pollutant.

These would all matter because they help evaluate whether the dumped chemicals are actually the cause.

So the useful question is:

Does this help us figure out whether the dumped chemicals caused the fin deformities?

If yes, eliminate it.

If no, that’s the answer.

___________

1. This gives us a baseline. If unexposed cod also have a 3% deformity rate, then Cod Bay’s rate may not be unusual. If unexposed cod almost never have deformed fins, that strengthens the claim that something in Cod Bay caused the deformities.
2. This tells us whether the deformities increased after the dumping. If the rate was already 3% before the chemicals, that weakens the claim. If the rate was basically zero before, that strengthens it.
3. CORRECT. People getting sick from eating the fish might matter for damages, public health, or consumer fear, but it does not tell us what caused the fin deformities. So it doesn’t help us evaluate whether the chemicals caused the deformities.
4. This tests an alternative cause. If a natural disease can cause the same deformity, then the chemical-waste explanation is less certain.
5. Similar to D; also tests an alternative cause. If other pollutants in the bay can alter genes, then the deformities may have been caused by something other than the companies’ dumped chemicals.