• 505 Videos, Slides, Films

• 140 Pollution
• 128 Ecological regions
• 116 Biotic communities
• 106 Conservation of natural resources
• 102 Environmental protection
• 99 Environmental policy
• 97 Environmental law
• 93 Air
• 93 Biodiversity
• 93 Climatic changes
• 88 Global warming
• 87 Natural resources
• 82 Biology
• 74 Life sciences
• 67 Ecology
• 60 Ecological zones
• 53 Water
• 52 Water use
• 44 Toxicology
• 43 Land use
• 41 Water-supply
• 38 Endangered ecosystems
• 38 Endangered species
• 38 Human ecology

• 460 Infobase
• 83 PBS (Firm)
• 42 BBC (Firm)
• 38 Green Planet Films (Firm)
• 33 Films for the Humanities & Sciences (Firm)
• 29 Film Ideas (Firm)
• 15 CNN (Firm)
• 15 TV Only SAS (Firm)
• 13 Annenberg Learner (Firm)
• 13 Green Interview (Firm)
• 12 Australian Broadcasting Corporation (Firm)
• 11 Bloomberg LP
• 10 CINEFETE (Firm)
• 10 Camille S. DeBose (Firm)
• 10 MacNeil/Lehrer Productions (Firm)
• 10 National Geographic Digital Media (Firm)
• 9 BBC Worldwide Learning (Firm)
• 9 Filmhub (Firm)
• 8 Mirror/Mirror Productions, Inc. (Firm)
• 8 Video Education America (VEA) (Firm)
• 7 National Geographic Society (U.S.)
• 6 Cerebellum Corporation (Firm)
• 6 Network Ireland Television (Firm)
• 5 Kwanza (Firm)

• 501 English
• 3 Unknown
• 1 Spanish

• 13 Earth (Planet)
• 6 Asia
• 5 United States
• 4 Africa, Sub-Saharan
• 4 North America
• 4 U.S. states
• 3 Africa
• 1 Antarctica
• 1 Australia
• 1 Central America
• 1 Physical geography
• 1 South America
• 1 South Asia
• 1 Southeast Asia

• 505 Internet videos
• 33 Educational films
• 33 Videorecording

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