Passage Summary: Shrimp populations at different reefs are genetically very different, which is weird because ocean currents should be mixing them all together into one big family.

Reasoning: No reasoning provided.

Analysis: The paradox here is the conflict between a mechanism for mixing (ocean currents carrying larvae) and the observed result of isolation (genetic differences). To resolve this, we need a piece of information that explains why the physical movement of larvae does not result in successful interbreeding between the reefs. Look for an answer that suggests the larvae don't survive the trip, don't settle in new reefs, or that some other barrier prevents them from contributing to the gene pool of a different population.