Algae first evolved in the oceans around 2.7 billion years ago. Following this, the concentration of oxygen in the Earth's atmosphere began to rise.
Explain how the evolution of algae and early plants caused this increase in oxygen.
Practise Edexcel GCSE Chemistry Earth and atmospheric science with exam-style questions for Foundation and Higher tier. 62 questions, matched to the Edexcel GCSE Chemistry (1CH0) specification and written in Paper 1 and Paper 2 style. Every question includes a full worked solution and mark scheme, so you can see where marks are awarded rather than just whether you got the answer right.
