It is necessary because if you don't have a confirmed opinion with textual evidence to back it up you wont have a good argument.
Answer:
I think you should leave that exact answer because compound sentences can be read as separate sentences once the conjunction is removed and still make sense.
Explanation:
Conjunction - word used to link two sentences. For example, but, and, or, yet, so, etc.
Fantasy is a genre of fiction that does not depict the real world.