Two scientists use a survey of a sedimentary basin to investigate how carbon dioxide was removed from the atmosphere over Earth's history.
Scientist A concludes that more carbon dioxide was removed by dissolving in the oceans and forming carbonate sediments.
Scientist B concludes that more carbon dioxide was removed by photosynthesis and the subsequent formation of fossil fuels.
The table shows the estimated mass of carbon currently stored in the basin.
| Carbon store | Estimated mass of carbon / billion tonnes |
|---|---|
| Carbonate sedimentary rock | 2800 |
| Coal | 12 |
| Crude oil and natural gas | 7 |
Using the evidence in the table, evaluate which scientist's conclusion is better supported.
79 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.