How did hammurabi become babylons king

Hammurabi became a king by inheriting the throne from his father.

Explanation:

His father had died due to failing health leaving his son Hammurabi as reigning king from 1792 BC to 1750 BC. He was the king of Amorites who through battles, alliances, and political manoeuvres was able to expand and rule over the entire Mesopotamia.  

Letters from the time when he was a leader state that one of his goals was to improve the lives of people he was leading. He is also famous for the development of the modern-day law code which served as code law for other cultures and influenced laws by Hebrew scribes.

d. i assume the underlined word is "role." reformat if it isn't.

explanation:

role is closest to part because when replacing words, "playing a vital decision," "playing a vital activity," and "playing a vital dollar" don't make logical sense. the only meaningful choice is "playing a vital part."

this fits one of merriam-webster's definitions of role: "a function or part performed especially in a particular operation or process."