ECONOMICS One of the main features of the barter system is that it: A. allows the government to control the money supply. B. requires all of its money to serve as tokens for goods. C. uses a variety of different currencies at once. D. makes trade possible without money,

They all make sense but i would go with D

Explanation:

If its not D then C because you need a lot of different currencies to trade different things.

to act quickly in times of danger to the united states

because you have to act quickly if you want to live/survive.

i think it's b