If you have trouble knowing how to revise for your exams this book provides comprehensive practice for the Edexcel AS biology unit 2 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 Edexcel 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 want.