Environmental Biology, one of the component of Environmental Science, deals with Inter-relation-ship between organisms and their environment. This book has been written in simple and lucid language under Indian context to provide basic information about environment and its relation with biotic component to the undergraduate science students of different universities of India. It is primarily meant to serve as a text book for the students, but this book will serve as a text and reference book for Students, Teachers and Research Workers and those who are going to sit for the different competitive examination.