I think the main element of Romantic music is Harmony or melody
It seems that you have missed some relevant details that can help us complete the answer, but anyway, this is what I can help. The correct answer would be issues of critical social importance. In Jean-Honoré Fragonard's Happy Accidents of the Swing, all of the following are characteristics of the Rococo and depicted in the painting except issues of critical social importance. Hope this helps.
