This students’ book has been written to assist secondary Biology Form Two students. The book meets all the requirements of the current syllabus. It also conforms to current international trends in the teaching of Biology.Biology is a practical subject which equips students with concepts and skills that come in handy in solving the day to day problems in life. The study of Biology aims at providing the learner with the necessary knowledge with which to control or change the environment for the benefit of an individual, family or community. This book recognises these aspects and provides adequate practical exercises to sharpen the students’ practical skills. In addition, it also provides study questions and end of topic questions for self evaluation. This book is written in a clear, concise language and is part of the Secondary Biology series.