How did the Mediterranean Sea contribute to the expansion of the Roman Republic?

The sea kept Rome from being invaded.
The sea allowed for trade east of the Alps.
The sea enabled easy travel for the military.
The sea required Romans to build roads for trade.

tearing down the berlin wall.

united states reinforcements contributed greatly to three allied victories in france at: cantigny (first major american battle), argonne (the largest in the united states military history, involving 1.2 million american soldiers), and château-thierry (one of the first actions under general pershing).

the answer should be a. the sui empire, the tang empire extended from korea in the west to manchuria in the east.