The mandate of heaven is the thing that Chinese emperors claim was given to them by their deities. A ruler earns it from the previous emperor when he retires, or when he dies. It could be lost when another dynasty takes over and takes the mandate of heaven.
A reason could be that trading food wasn’t that popular at the time seeing that you only needed to grow food for your family
Uhhh need more info for an answer
Books back then were hand written and made by hand so it took a lot of time an hard work to assemble one, that's the reason they were so expensive.
