Answer:
1. Earth viewed from space - Remote Sensing Test
2. Commanded first ship to sail around Earth - History Test
3. 7,900 miles mantle - Geology Test
4. Hills, valleys, rivers, plains - Geography Test
5. Layer below crust diameter at poles - Geophysics Test
6. At Earth's center landforms - Geophysics Test
7. About 3,000 types a large sphere - Astronomy Test