Question: I was studing how to say school subjects in mandarin and I saw this sentence:

我最喜欢的科目**有**艺术，中文和化学
(My favorite school subjects are art, chinese and chemistry)

Why the use of 有 in this sentecence?

Could I say/write: 我最喜欢的科目是**是**艺术，中文和体育

Answer: 
I have some issues with the first sentence, though it is not wrong. I would say:

我最喜欢的科目有三個 - 艺术，中文和化学 (There are three of my most favored school subjects - ... or

我最喜欢的科目包括 艺术，中文和化学 (My most favored school subjects include ....

The second sentence is perfectly correct.
Both are ok.

Why the use of 有 in this sentecence? Because here the "科目" in "我最喜欢的科目" is kinda list, so we can say "我最喜欢的科目有艺术，中文和化学", there are Art, Chinese etc in the list. "有" is the same meaning of "there are"