The essence of biological understanding is to know how organisms, while remaining an individual, interact with other organisms and physical habitats as a group and hence behave like organised wholes, i.e., population, community, ecosystem or even as the whole biosphere. Download NCERT Class 12 Biology Books in English and Hindi PDF for free. Find the chapter on Organisms and Populations in the English medium book. Get chapterwise CBSE Class 12 Biology NCERT Books PDF online. Class 12 Biology book Chapter 13. Organisms & Populations in English Download in Pdf. Books for Class 6 to 12 all subjects Chapter wise in hindi and english Medium