The book has been prepared in question-answer form and intends to serve as a complete study material in Science for Class X students. The main objective of the book is to provide students with step-by-step module to prepare well for the examinations. The salient features of Mentor in Science are: A detailed summary of important concepts covered in the textbook has been given at the beginning of each chapter. Complete solutions to NCERT intext questions, Textbook Exercises as well as Exercises from the Book EXEMPLAR have been included. Important additional questions and numerical problems of varying difficulty level have been incorporated in each chapter. Questions form CBSE latest Examination paper and Sample Paper have been added with answers. The questions have been arranged systematically in MCQs, Assertion-Reason type, very short answer type, short answer type and long answer type questions. Case based questions have also been included in each chapter. The length of the answers has been especially kept in mind to enable students to write accordingly in the examinations. The language has been kept simple and lucid for the clear understanding. Neatly labelled colourful diagrams have been included wherever required.