The dutch were the only europeans allowed to trade with japan as long as they a. paid tribute to the emperorb. gave up all show of christianityc. converted to buddhism d. also traded with the chinese

monarchy doesn’t have to have the hereditary element. there have been elective monarchies in the past where you choose your king-for-life and when he dies elect someone else for the job.

i think it was because of how protected egyptian civilization was was which allowed them to evolve without much outside influence.