A space scientist compares the atmospheres of two planets that formed in a similar way to the Earth.
| Planet | Life known on the planet | Carbon dioxide (%) | Nitrogen (%) |
|---|---|---|---|
| Venus | none | 96 | 3 |
| Mars | none | 95 | 3 |
Which statement about the Earth is best supported by these data?
The Earth's early atmosphere probably had little carbon dioxide until living things released it.
The Earth's early atmosphere was probably mostly carbon dioxide, with a few per cent nitrogen.
The Earth's early atmosphere was probably mostly carbon dioxide, with a few per cent oxygen.
The Earth's early atmosphere was probably much the same as the Earth's atmosphere today.
109 exam-style questions on OCR GCSE Chemistry 6.3 Interpreting and interacting with earth systems, covering 6.3.1 Formation and evolution of the atmosphere, 6.3.2 The greenhouse effect and climate change, 6.3.3 Sources and problems of atmospheric pollutants, and 6.3.4 Producing potable water. Each one has a worked solution and a mark scheme showing where the marks go.