38 exam-style questions on Edexcel GCSE Biology 9.2 Energy transfer and biodiversity, covering 9.2.1 Energy transfer between trophic levels, 9.2.2 Efficiency of energy transfers, 9.2.3 Human interactions and biodiversity, 9.2.4 Benefits of maintaining biodiversity, and 9.2.5 Biological factors affecting food security. Each one has a worked solution and a mark scheme showing where the marks go.