A seismograph detects P-waves but no S-waves at a station located across the globe. What can scientists conclude about Earth's structure?

S-waves cannot travel through liquids, while P-waves can travel through both solids and liquids. If the station detects P-waves but no S-waves, the S-waves were likely stopped by a liquid layer inside Earth. This supports choice A; it does not mean that S-waves are faster or that Earth has no liquid layers.

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