PrepTest 135, Section 4, Question 6
The calm, shallow waters of coastal estuaries are(42 more words not shown)
Which one of the following(8 more words not shown)
- AFish in an(29 more words not shown)
- BIn estuary waters(18 more words not shown)
- CNutrients and other(22 more words not shown)
- DAlgae will not(11 more words not shown)
- EOvernutrifying estuary waters(15 more words not shown)
Reading the argument
Follow the food. Nutrient-rich sewage overfeeds the estuary, algae multiply, and those algae sometimes feed microorganisms that are toxic to fish. The result can be the death of most of the fish.
That's a chain we can connect from beginning to end. We don't need a new theory about pollution; we need an inference that stays within this account. Overnutrification from sewage can have deadly consequences for the fish through these intermediate steps.
What we’re looking for
Keep 'sometimes' in the chain. The passage doesn't say every increase in algae produces the toxic microorganisms, or that every fish dies. An answer saying this can happen is supported; an answer saying it always happens would go too far.
Working the answers
- A
We haven't compared sewage pollution with other kinds of pollution. Another pollutant could be even more dangerous to fish. Explaining one harmful process doesn't rank it against processes the passage never discusses.
- B
The passage identifies a food source for microorganisms toxic to fish. It doesn't compare their reproduction with that of other microorganisms. Other types might also thrive when algae are abundant, perhaps even more quickly.
- C
This turns one route to harm into the only route. Perhaps some sewage component could harm a fish directly, without first producing more toxic microorganisms. The passage doesn't rule that out. We know how sewage can harm fish, not every way it can do so.
- D
Sewage supplies one way to produce an abundance of algae. It isn't established as the only way. Perhaps more sunlight could also promote algae growth. That is a possible alternative, not a fact established here. We can't infer that algae will stay under control whenever this particular pollutant is absent.
- ECorrect
This connects the first step to the last: sewage can overnutrify the water, encourage algae, feed toxic microorganisms, and thereby kill most of the fish. 'Can result' preserves the passage's limited claim. It doesn't turn the sometimes-occurring process into an inevitable outcome.
More Must Be True questions
Learn the LSAT our way
Our platform drills Must Be True questions at your level and adjusts as you improve.