Waht caused japanese disunity from the 1300s to the 1500s

From 1300s to 1500s, which is about two centuries, Japan tore itself apart in the feudal wars and all the civil conflicts. Due to Minamoto's victory, Japan transitioned to medieval feudalism and power rested upon two shogun regimes, the Kamakur and Ashikaga. 

        i'm fairly sure that the correct answers are 2 and 3.

        i used both my knowledge of world history and the process of elimination to obtain these answers. option 1 cannot be a possible selection because the mandate of heaven belongs to ancient chinese philosophical belief. option 4 sounds like it would benefit the region than detriment it. however, both 2 and 3 explain a potential reason for what could have contributed to the fall of the roman empire.

      hope this ! if i were you, i'd get a second opinion, because i haven't taken this course for a year. best of luck!

***websites that me understand the curriculum better last year are and ***