This Biology text is intended to support Tanzanian students in Form I, who are beginning to learn subjects in English. When Form I students start learning subjects in English, they often find that they cannot use the language well enough to learn effectively. Learning in English is also difficult because everything they know already from primary school was learnt in Kiswahili. Language accessible: This means it is written in a simple way, with diagrams that allow all students in Form I to read it. Language supportive:This means that the textbook helps students to develop their English as they learn Biology. Relevant to learners’ context: Biology is about the living world around us. Learning Biology is easier and more interesting when it is contextualized.So this book is filled with examples from learners’ context The result, we think, is a great book that will be easy for teachers to use, and for students to learn from. Above all it will show students that learning Biology is a wonderful, relevant and exciting journey. We hope you enjoy using it with your students as much as we enjoyed writing it.