Use one of the options below to complete the sentence about the history of the Earth's atmosphere. Over the past 4 billion years, the percentage of nitrogen in the Earth's atmosphere has ____________.
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.
