There would be no seperation between one country's economy and another's if the entire world

Had the same currency.

Explanation:

Most countries have their own form of money (currency) which is traded and valued at different rates. If the entire world had the same currency then trade and purchases would be equalized across the globe and there would be less separation between economies.

c.

explanation:

regressive tax taxes the poor and less of the wealthy. this the rich get richer and the poor get more poor. this would create a large wealth gap.