The geographic barrier to the south is the: -Gobi Desert
-Altai Mountains
-South China Sea

The East China Sea is a geographic barrier to the:
-East
-North
-West

The Gobi desert is a geographic barrier to the:
-East
-North
-South

1. crust 1 the metallic layer at the earth's center 2. inner core 3 the firm layer between the crust and the asthenosphere 3. lower mantle 2 the layer surrounding the inner core 4. asthenosphere 4 the semi-solid layer between the top layer and the upper mantle 5. upper mantle 5 the layer between the asthenosphere and lower mantle 6. top layer 6 the earth's outermost layer 7. outer core 7 the hottest part of the mantle