| A | B |
|---|
| trace fossil | fossils of the evidence of once living organisms, includes tracks and burrows |
| sedimentary rock | rocks formed from the accumulation of seperate particles, from rock that are squeezed together |
| Precambrian | the time betweeen Earth's formation 4.6 billion years ago and the beginning of the paleozoic |
| plates | moving rigid blocks of Earth's crust and upper mantle |
| plate techtonics | the theory that Earth's crust is made up of plates, some with continents, that slowly move |
| Pangea | a continent thought to exist during the Mesozoic Era that included most of Earth's present day continents |
| paleontologist | a scientist who studies fossils |
| outer core | the layer of liquid metal between Earth's mantle and the inner core |
| Mesozoic Era | a major geologic era that covered the time period from about 250 to 65 million years ago; age of the reptiles |
| mantle | middle layer of Earth located between the crust and outer core |
| inner core | the solid ball of iron and nickel at the center of the Earth |
| iceberg | a large mass of floating ice that has broken off from a glacier or polar ice cap |
| glacier | a large mass of ice moving slowly over Earth's surface |
| geology | the science that deals with the Earth's structure |
| geologic era | one of several periods in geologic history |
| erosion | the process that happens when glaciers, running water, waves, or wind carry away the soil and rock on Earth's surface |
| crust | the outermost layer of the Earth's surface |
| continental drift | the hypothesis that the continents have been slowly moving across Earth's surface and changing their positions |
| Cenozoic Era | an era of geologic time that began about 65 million years ago and extends to the present |
| Big Bang Theory | a theory stating that the universe originated from the explosion of a dense mass of matter that cooled, collected into clouds, and formed billions of galaxies and stars |
