Biosphere 35 Ecology 11 Ecology- Gulf of Mannar 8 Hydrosphere 6 BIOSPHERE 5 Lithosphere 5 Biology 4 Ecosystem 4 ATMOSPHERE 3 Atmosphere 3 Biochemical Phenomena 3 Biogeography 3 Climatology 3 Earth sciences 3 Environment 3 Environment-India 3 Environmental Microbiology 3 Environmental chemistry 3 Genome 3 HYDROSPHERE 3 Natural resources 3 biosphere 3 Air pollution 2 Bioethics 2 Biological resources 2 Biophysics 2 Biotic communities 2 CHEMICAL TOXICOLOGY 2 ENVIRONMENTAL BIOCHEMISTRY 2 Ecology-- Biodiversity-- Conservation 2