| A | B |
|---|
| orbit | path one body makes as it circles around another |
| revolution | circular motion |
| axis | an imaginary line running through Earth between the North and South poles |
| rotation | complete turn of the Earth that takes 24 hours |
| core | a sphere of very hot metal located at the center of the Earth |
| mantle | the thick, hot, rocky layer around the core. |
| crust | thin layer of rocks and minerals that surround the mantle |
| magma | soft, nearly molten rock |
| plates | huge blocks of the Earth's crust |
| weathering | the process that breaks rocks down into tiny pieces |
| erosion | removal of small pieces of rock by water, ice, or wind |
| weather | the condition of the air and sky from day to day |
| precipitation | water that falls to the ground as rain, sleet, hail or snow |
| temperature | how hot or cold the air is |
| climate | the average weather over many years |
| Tropical cyclones | intense wind and rain storms that form over oceans in the tropics |
| vegetation | plants that grow in a region |
| tundra | area near the Arctic Circle, of cold climate and low-lying vegetation |
| canopy | dense leafy layer at the top of the rainforest |
| savanna | parklike landscape of grasslands scattered with trees |
| desert scrub | low desert vegetation that needs little water |
| deciduous trees | trees that lose their leaves in the fall |
| coniferous trees | trees that produce cones to carry seeds |
