The domain of Life Science stands as a beacon, illuminating our exploration of the living world. This book ‘Guide Book of Life Sciences’ embodies an earnest effort to compile a comprehensive practice guide that not only aligns with the respective syllabi but also maintains the standards expected in the previous papers of different national exams in Life Science and its related branches. The examinations primarily focused on in this book include the CSIR-NET (Life Science), DBT-JRF (BET), GATE (Biotechnology) and GATE (Life Science).A distinctive feature of this book is the inclusion of over 3300+ multiple-choice questions (MCQs) derived from the past six years’ papers. This is reflective of a pattern of minor trend shifts that occur at approximately five-year intervals. This book is prepared after a meticulous analysis of unit or topic-wise questions (with corresponding subtopics in Biology), deliberately excludes aptitude-based questions. It serves to enable students to review and understand the pattern of questions, analyze the content for preparation, and understand the changing trends.