A workbook to aid your revision, this book provides comprehensive practice for the OCR A2 biology unit 4 exam. It includes extensive questions to test your basic knowledge of all the key concepts included in this particular exam. Flow diagrams for all the processes depicted by the OCR specification are provided in order to aid your understanding. In addition, details of the questions covered in previous exams and longer practice questions for those more tricky topics. Everything you need to get the grade you deserve.