Thank you Dave (yes this helped). I discovered another problem with the different screen sizes, so I would like to ask a follow-up question.
I have one radiobuttons question where people should see a text and picture as the answer categories. I couldn't figure out how to add a picture to the radiobutton, so I added pictures and placed them next to the answer options. However, with different screens, the pictures will not be displayed next to the answer options. So, after all, is there a way to include pictures as options for the radiobuttens element?
This is the code now:
<radiobuttons nationality>
/ caption = "What is your nationality?"
/ options = ("~nGerman~n", "~nPortuguese~n")
/ optionvalues = ("Germany", "Portugal", "none")
/ other = "Other"
</radiobuttons>
<picture GermanFlagRadioquestion>
/ items = ("stimulusMaterial/Flag_of_Germany.png")
/ position = (24, 63)
/ size = (9%, 9%)
</picture>
<picture PortugalFlagRadioquestion>
/ items = ("stimulusMaterial/Flag_of_Portugal.png")
/ position = (24, 75)
/ size = (9%, 9%)
</picture>
<surveypage iniNat>
/ caption = " During the game, you will always see the initials and nationality of the other Player, as well as your own. Before starting the game, please answer the following questions:"
/ fontstyle = ("Calibri", 2.8%, true, false, false, false, 5, 0)
/ questions = [1=initial1; 2=initial2; 3=nationality]
/ stimulusframes = [1 = GermanFlagRadioquestion; 2= PortugalFlagRadioquestion]
</surveypage>
<block initialsNation>
/ trials = [1=iniNat]
</block>