| A | B |
|---|
| radioactive decay | causes convection currents in mantle |
| core | made of iron and nickel |
| oceanic plate (crust) | floats on mantle |
| earthquakes | may occur where plates meet |
| 4.3 billion years | approx age of Earth |
| source of water for oceans | condensed steam/vapour from volcanoes/lava |
| continental drift | Alfred Wegener's idea |
| plate tectonics | explains movement of continents |
| dissolution | carbon dioxide reacting/dissolving in oceans |
| chalk/limestone | rocks that lock away carbon dioxide |
| algae | life forms that used carbon dioxide for photosynthesis |
| Millier Urey experiment | primordial soup;origin of life |
| carbon dioxide,ammonia,methane | from volcanoes |
