The most formal of political organizations and one of the hallmarks of civilization, this type of political organization has a centralized government that may legitimately use force to regulate the affairs of its citizens, as well as its relations with other similar political systems. it is called

It is called a STATE GOVERNMENT.

Explanation:

A state government refers to a government who initiate and enforces laws of a state.

Examples of nations with such government are Australia, India and United States in which the state is responsible for providing the needs of the citizens. They have more power than the national government.

State government cater to needs of their local citizens and issues that a particular state is facing. This constitution guides the state , in the United States with its fifty states the constitution assist in how the power is distributed , policies made, what rights citizens have , and how they should elect officials.

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."