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