It what ways are a Command economic system and a Mixed Market economic system
different?

In a command economy, the system is controlled by the government. A mixed economy is partly run by the government and partly as a free market economy, which is an economic system that includes no government intervention and is mainly driven by the law of supply and demand.

the answer to this question is d

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."