This image was acquired from
wikimedia. It was marked as Public Domain or CC0 and is free to use. To verify, go to the source and check the information there.
Keywords from Image Description:
Selection for nonnatural aa.svg two step selection Transferred from org en transferred to Commons by User Magnus Manske using de php CommonsHelper br Original text Squidonius talk created this work entirely by myself October UTC br first version last version Squidonius talk Original uploader was Squidonius at org