Ecological science, the Biosphere 4 Teaching of a specific subject 4 Biodiversity 3 Conservation of wildlife & habitats 3 Face recognition 3 Limnology (freshwater) 3 nonhuman 3 19th century, c 1800 to c 1899 2 Article 2 Canada 2 Face detection 2 History of the Americas 2 Islamic life & practice 2 Law 2 Legal history 2 Literature: history and criticism 2 Media studies 2 Religion & beliefs 2 Religious aspects of sexuality, gender & relationships 2 Religious groups: social & cultural aspects 2 Sociology 2 Technology: general issues 2 Viola-Jones algorithm 2 18th century, c 1700 to c 1799 1 20th century, c 1900 to c 1999 1 21st century, c 2000 to c 2100 1 Accidents. Prevention of accidents 1 Acoustic data 1 Acoustics 1 Agrophytocenosis 1