What do the members of the United Nations have in common? A. They promise to provide peacekeepers to resolve conflicts.
B. They have democratic governments.
C. They follow the rules of free trade.
D. They are internationally recognized nations.

Explanation:

they promised to provide peacekeepers to resolve conflicts

(d) rivers.

explanation:

civilizations developed around rivers because their waters provided places to hunt and fish. also, as the rivers flooded, the lands around them became fertile. this allowed them to support farming. this is especially true of the nile river, which flooded the same time each year.

it took two men to wrestle rome back from chaos and turn a republic into an empire. in the first century bc, rome was a republic. power lay in the hands of the senate, elected by roman citizens. but the senators were fighting for power between themselves.