<span> A. Moho barrier </span>The Moho<span> is the boundary between the crust and the mantle in the earth.
</span><span>B. Oceanic crust </span>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
<span>Lower mantle </span>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.
<span>upper mantle </span>The upper mantle<span> begins just beneath the crust and ends at the lower mantle. </span> hope this helps you(:
