GCSE Biology OCR 21st Century Revision Guide This book is full of detailed revision notes and clear diagrams for GCSE Biology students. It covers every topic for the OCR 21st Century year 10 and 11 exams. The whole thing's designed to make revision straightforward - each section is split into a topic per page, with questions to check what you've learnt at the end. It's all explained simply and thoroughly with lots of handy exam tips and guidance on 'Ideas about Science' and the Controlled Assessment.