What is the boundary that separates the Earth's crust from the upper part of the Asthenosphere called?

The correct term for the boundary that separates the Earth's crust from the upper part of the Asthenosphere is the Mohorovicic Discontinuity, often referred to simply as the "Moho." This boundary represents a significant change in material properties; it separates the lighter, less dense rocks of the crust from the denser, more malleable rocks of the upper mantle.

At the Moho, there is a noticeable increase in seismic wave velocities, which indicates the transition from crustal material primarily composed of silicate minerals to the denser rocks found in the Asthenosphere. This understanding is crucial in the field of geology and seismology, as it helps scientists interpret geological processes and the behavior of seismic waves.

The other options do represent different geological concepts but do not specifically denote the boundary in question. The Geologic Boundary is a more general term that does not point to a specific separation within the Earth. A Plate Boundary refers to the edges where tectonic plates meet, relevant in the context of tectonic activity but not in the context of crust and asthenosphere separation. The term Crust-Asthenosphere Boundary is not a widely recognized or standard term in geoscience; instead, the Mohorovicic Discontinu