Which group of gases is thought to have made up the majority of Earth's early atmosphere, before the development of photosynthetic life?
Oxygen, nitrogen, and carbon dioxide
Carbon dioxide, water vapour, and nitrogen
Methane, oxygen, and helium
Chlorine, argon, and oxygen
32 exam-style questions on OCR GCSE Chemistry Interpreting and interacting with earth systems. Each one has a worked solution and a mark scheme showing where the marks go.