Which most accurately describes events during kublai khan's rule of the mongol empire (yuan dynasty)?

Kublai khan is the reason why chaos stated in the Mongol Empire. He defeated and killed the Mongol leader Genghis Khan. After the assassination there was lot of disturbance in the empire and thus started the civil war. He abolished Chinese Confucianism and made the empire follow Mongol paganism. He made wall of china securing the borders. He also improved the trade from east and west by welcoming Marco Polo to the empire.