The propagation of seismic waves through Earth's interior provides evidence of internal layering. The first boundary discovered was the boundary between the
A)upper and lower mantle.
B)inner and outer core.
C)outer core and the mantle.
D)mantle and the crust.

Question

Quizplus · Accepted Answer

The boundary between the outer core and the mantle was the first discovered, evidenced by the reflection and refraction of seismic waves at this boundary, indicating a significant change in material properties.

The Propagation of Seismic Waves Through Earth's Interior Provides Evidence