What natural resource was used in ship-building?

Wood

Explanation:

In order to build ships wood was crucial to ship building back then.

the money supply is the total amount of money available in the economy. how do changes in the money supply affect people and businesses?

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."