Answer:
They form the argument’s main point.
Explanation:
In a written argument reasons and evidence form the argument's main point. There has to be an explanation that is backed by actual evidence for that argument existing in the first place, otherwise the entire argument is made mute. The involved characters in the argument usually go to certain lengths to win/resolve the argument but if the entire argument is not backed by reasons and evidence then it opens up huge plot holes as the characters are making all their choices for no actual reason.
