Practise Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion with exam-style questions for Foundation and Higher tier. 17 questions covering 8.1.1 Introduction to exchange and transport, 8.1.2 Alveoli adapted for gas exchange, 8.1.3 Factors affecting rate of diffusion, and 8.1.4 Rate of diffusion using Fick's law, matched to the Edexcel GCSE Biology (1BI0) 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.