| Rock that has been liquefied by heat is ____ (melted). |
billion |
| Heat and pressure are required to create ____ rocks. |
gibbous |
| The molten rock below the Earth's surface is called ____. |
lava |
| The Earth was formed about 4.5 ____ years ago. |
magma |
| Amber, coral, pearl, and shell are ____ (unlike true minerals). |
metamorphic |
| The molten rock expelled by a volcano is called ____. |
molten |
| Earthquakes create ____ waves, which are sound waves. |
organic |
| New, crescent, quarter, ____, and full describe lunar phases. |
seismic |
