Passage Summary: In a cave with millions of bats, moms and babies find each other by sound. Since the babies can't tell which voice is their mom's, the moms must be the ones who recognize their baby's voice.

Conclusion: Mother bats possess the ability to identify the unique calls of their offspring.

Reasoning: Reunions between mothers and pups occur via sound, and since pups are unable to identify their mothers' calls, the mothers must be the ones doing the identifying.

Analysis: The argument functions by identifying a phenomenon—the successful reunion of bats—and then narrowing down the possible mechanisms for that phenomenon. Since the stimulus limits the interaction to calls and explicitly rules out the pup's ability to recognize the mother, it concludes by default that the mother must recognize the pup. This is a 'process of elimination' or 'inference to the best explanation' structure. Focus on how the argument assigns a specific role to one party after proving the other party is incapable of it.