The Mongol invasions

How did the Mongol invasions contribute to the fall of the Kamakura regime?
What is the Kenmu Restoration?
Kamakura sent two armies to destroy Emperor Godaigo’s rebellion. What happened?
What is the era of Northern and Southern Courts?
How did Ashikaga Yoshimitsu solve the two courts problem?
What can you say about samurai loyalty based on the history of Ashikaga shoguns?