Why did the writers have grendel being hrothgars son

Explanation:  

I think this made for a more understandable plot point for people, as most of them were, who had never read the play before. Hrothgar would have had made a deal with the Devil and Grendel would have been the consequence. It's the sort of bargain that we might see in Faust or Macbeth.

16.) true

17.) true

18.) it doesn't say

19.) true

20.) false

explanation: