What is the main difference between sunni and shiite islam? what are three similarities?

Both sides agreed that Allah is the one true God and that Muhammad was his messenger, but one group (which eventually became the Shiites) felt Muhammad's successor should be someone in his bloodline, while the other (which became the Sunnis) felt a pious individual who would follow the Prophet's customs was acceptable.

this is what i put and it was correct

it's a way for authors to communicate with reader in this time period. books from the past can teach us about life.