Coal is a fossil fuel. The figure shows the layers of rock in which a seam of coal is found.
Figure: The layers of rock in which a seam of coal is found

Name the type of organism from which coal was formed.
Describe how the plant material was changed into coal.
Explain why the plant material did not decay away completely.
40 exam-style questions on AQA GCSE Chemistry 9.1 The composition and evolution of the Earth's atmosphere, covering 9.1.1 The proportions of different gases in the atmosphere, 9.1.2 The Earth's early atmosphere, 9.1.3 How oxygen increased, and 9.1.4 How carbon dioxide decreased. Each one has a worked solution and a mark scheme showing where the marks go.