Question

Good morning, help im dum

Answer 1

A. Moho barrier   The Moho is the boundary between the crust and the mantle in the earth.

B. Oceanic crust 
is the uppermost layer of the oceanic portion of a tectonic plate. The crust overlies the solidified and uppermost layer of the mantle. The crust and the solid mantle layer together constitute oceanic 

Lower mantle 
A large fraction of Earth's interior, from a depth of about 650 km (400 miles) down to 2,900 km (1,800 miles), consists of the lower mantle, which is composed chiefly of magnesium- and iron-bearing silicates, including the high-pressure equivalents of olivine and pyroxene.

upper mantle 
The upper mantle begins just beneath the crust and ends at the lower mantle.

hope this helps you(:

if not plz let me know(;