Bildquellen
Frage 1:
© Luxembourg Science Center – Jo Hoeser
Frage 2:
© Luxembourg Science Center – Jo Hoeser
Frage 3:
© Luxembourg Science Center – Jo Hoeser
Frage 4:
This file is licensed under the Creative Commons Attribution-Share Alike 4.0 International license. https://commons.wikimedia.org/wiki/File:Photoreceptor_cell.jpg
Frage 5:
© Luxembourg Science Center – Jo Hoeser
Frage 6:
https://commons.wikimedia.org/wiki/File:Ishihara_11.PNG
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© Luxembourg Science Center – Jo Hoeser
Frage 8:
https://commons.wikimedia.org/wiki/File:All-trans-Retinol2.svg