Note that your final mark will not be saved in the system.
Geological Timescales Typeit
Type the correct answers into the spaces. Fill all the spaces before clicking ‘Check Answers!’
Ice Ages and Interglacials
If you had visited Earth soon after it was first formed, you wouldn't have been able to breathe! That's because there was no . It was also so hot that water only existed as . Since then there have been times when Earth has down naturally. At these times, spread from the polar regions and changed the shape of the land. We refer to those times as periods and the much warmer periods between them as periods. When there was lots of water trapped as ice, the sea was much lower. It would have been possible, for example, to walk across the from France. At other times, places where we can now walk on dry land would have been submerged beneath the . The ice last retreated from the British Isles about ten years ago and the climate was quite stable for a time. Now, however, humans have pumped so many millions of tonnes of into the air that the average temperature of Earth has started to increase artificially. We call this .