By Gregg Treinish, National Geographic Kids, Kitson Jazynka
By Desmond Morris
By Ishii Takayuki
By Harvey, Anne, Mckenna, Virginia, Lovatt-Smith, Tessa
By Harvey, Anne, Geldart, WILLIAM
By Vorderman, Carol
By Hunter, Erin
By Steve Parker
By Alan Morton
By Isabel Thomas
By Advanced Physics Project for Independent Learning
By Briggs, Raymond
By United Nations Environment Programme
By Bob Digby, Becky Priest, Becky Tudor, Andy Slater, David Holmes
By Grant, Michael
By Lawrence James Campbell, R.J. Carlton
By Muirden James
By Ignotofsky, Rachel
By Andrew Solway
By Branwen Thomas
By Chris Ryan, Ryan, Chris
By Roger Priddy
By Williams, David J.
By Muriel Mandell, Frances Zweifel
By Beckett, B. S., B. S. Beckett
By BBC
By Adrian Forsyth, Laurel Aziz
By Cath Senker