LSAT 2 | Section 4 | Logical Reasoning: Q7

LR Question 7 Explanation

QUESTION TEXT: Marine biologists have long thought that variation…

QUESTION TYPE: Strengthen

ANALYSIS: Do not look at the answer choices on this sort of question unless you’re sure what you’re looking for. You’ll just get confused.

The old theory was that dark shells occur with dark sea beds, and white shells occur with white sea beds.

The new theory is that dark shells occur with waves, and light shells occur with calm waters.

We want a situation that is consistent with the new theory and inconsistent with the old theory. The shells should not match the sea floor, and there should be predators. For example: wavy waters, dark shells, white seabed, lots of predators.

Or: calm waters, white shells, dark seabed, many predators. This one is answer choice D.

___________

1. This is what the old theory would predict.
2. The new theory predicts that calm waters cause white shells.
3. The new theory predicts wavy waters will lead to dark shells.
4. CORRECT. Yes. The old theory predicts these snails would be eaten by predators. The new theory predicts that any snails in a calm inlet will be white shelled no matter the color of the sea floor.
5. This is consistent with both theories and doesn’t let us prove anything.

Recap: The question begins with “Marine biologists have long thought that variation”. It is a Strengthen question. Learn how to master LSAT Strengthen questions on the LSAT Logical Reasoning question types page.