By what was north america was isolated from the rest of the world?

a.
technology

b.
religion

c.
shipbuilding

d.
water

I believe the answer would be d water because geographically the United States is surrounded by water therefore isolating it from the rest of the world

The answer is c.shipbuilding because  people across political and geographic boundaries, has helped spread some of the deadliest infectious diseases known to humans.The spread of diseases across wide geographic scales has increased through history. and Early diseases that spread from Asia to Europe were bubonic plague, influenza of various types, and similar infectious diseases.

S^2 = a4^2 = a4 * 4 = a16 centimeters = area of the square