| A | B |
|---|
| axis | the imaginary line through the middle of the Earth around which it spins |
| orbit | a kind of stretched out circle that the earth makes around the sun |
| gravitation | the pull that everything in space has on everything else |
| crust | the outside of the earth that is like a shell of rock |
| mantle | the layer of Earth just below the crust that is made of a different kind of rock than the crust |
| outer core | the layer of melted metal that is beneath the mantle |
| inner core | in the center of the Earth, a ball of hot, solid, squeezed-together metal about 1,600 miles thick. |
| continent | a great platform of rock that sticks up a little higher than the rest of the rocky crust |
| islands | the top of an underwater mountain or part of a continent that has become separated from t he rest of the continent |
| three-fourths | the area of the Earth's crust that is covered by water |
