(12) http://en.wikipedia.org/wiki/File:Hazard_O.svg
http://en.wikipedia.org/wiki/File:Hazard_T.svg
http://en.wikipedia.org/wiki/File:High_voltage_warning.svg. Public
Domain,GNU-FDL.
(13) http://en.wikipedia.org/wiki/File:Cropscientist.jpg. Public Domain.
(14) http://en.wikipedia.org/wiki/Image:Moon_formation.jpg. Public Domain.
(15) Outdoor Excursions.. GNU-FDL.
(16) http://en.wikipedia.org/wiki/File:Different_minerals.jpg. GNU-FDL.
(17) http://en.wikipedia.org/wiki/File:Waves_in_pacifica_1.jpg. GNU-FDL.
(18) http://en.wikipedia.org/wiki/Image:Rainbow_Basin.jpg. GNU-FDL.
(19) http://commons.wikimedia.org/wiki/File:
Seismometer_at_Lick_Observatory.JPG. Public Domain.