Two organisms have the same shape but different sizes. The larger organism has more cells far from its outer surface.
Which combination explains why the larger organism needs a transport system?
smaller surface area to volume ratio and longer diffusion distances
larger surface area to volume ratio and longer diffusion distances
smaller surface area to volume ratio and shorter diffusion distances
larger surface area to volume ratio and shorter diffusion distances
42 exam-style questions on Edexcel GCSE Biology 8.1 Exchange surfaces and diffusion, 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. Each one has a worked solution and a mark scheme showing where the marks go.