Topics are presented as double page spreads (learning units) so that material is presented in manageable sections. The reading age has been carefully controlled, and the text written to ensure clear and unambiguous explanations. Great care has been taken with the sequencing and development of concepts, while assuming that the student had only an average grade at GCSE level. More difficult sections are clearly marked so that they can be omitted at first.Each chapter has a concise summary of the work covered. A large number of questions are included, for students to practise and develop their competence. Biology at Work sections give many applications of chemistry throughout the book. It includes sections on Key Skills in Biology, 'Practical Skills and Study Skills.