Changes which take place and have taken place in the Earth's crust, biosphere and atmosphere are all studied in GCSE Science. This is the last of three quizzes on that topic and it looks in particular at carbon dioxide and the carbon cycle.
The Earth's atmosphere has undergone many dramatic changes since it was formed around four billion years ago - and it is still changing today. It has been much the same for the last 200 million years or so and provides the conditions needed for life as we know it on Earth. Recently, human activities have resulted in further changes in Earth's atmosphere. One of the gases that we send into the atmosphere is carbon dioxide. This is thought by many to be causing changes to the world's climate.