"School subjects" or something along the lines is perfectly acceptable answer for the classical arts. And I typed "Greek and Latin" for the grid containing "sociology," but it didn't take. I think the answers in the musical scale category are way short for anyone to be likely to recognize or think to look for them.

@SonJonath thanks for the comments, this was my first puzzle so I wasn’t quite sure how to go about filling in the answering key words. Your input was helpful for going forward