This document is the teacher's guide for the 10th grade science textbook published by the Department of Education of the Philippines. It provides an overview of the textbook's contents, including introductions, learning objectives, and lesson plans for four modules that cover topics related to living things and their environment: 1) the coordinated functions of the nervous, endocrine and reproductive systems, 2) heredity and inheritance, 3) biodiversity and evolution, and 4) ecosystems and environmental issues. The document also lists the authors and reviewers involved in developing the textbook and provides publishing details and copyright information.