What kinds of themes or topics can graphic novels cover?

Any.

Explanation:

Graphic novels are just like books, they can cover themes, and topics.

a phrase is a set of word that make a sense, an expression formed by two or more words.

" teacher´s dictum on the possession of human "

" made a pile practicing "

" lived to an impressive age and dies "

a clause, in a grammar way is a series of words that have a complete meaning.

" was irritated by the persecution of those who called themselves "

"the sandy walls seemed to collapse in on themselves"

and

"the bloodshot waters seemed to have no bottom"