Question

How do seismic waves help scientists understand Earth's layers? Select the two correct answers.(1 point)
Responses

Scientists can observe which seismic waves change the composition of the layers they pass through.
Scientists can observe which seismic waves change the composition of the layers they pass through.

Scientists can generate seismic waves in order to observe their paths through Earth.
Scientists can generate seismic waves in order to observe their paths through Earth.

Scientists can observe how seismic waves change speeds when passing through different layers.
Scientists can observe how seismic waves change speeds when passing through different layers.

Scientists can observe how seismic waves multiply when passing through different layers.
Scientists can observe how seismic waves multiply when passing through different layers.

Scientists can observe which seismic waves cannot pass through certain layers.

Answer 1

- Scientists can observe how seismic waves change speeds when passing through different layers.
- Scientists can observe which seismic waves cannot pass through certain layers.

Brief why: Speed changes (refraction) reveal differences in density/composition of layers, and the fact that S-waves don’t travel through liquids helped show Earth’s outer core is liquid.