Answer:
allow for the movement of goods, services, and people across borders and to eliminate tariffs among member nations
The answer is form a hypothesis.
It promoted the (relatively) rapid diffusion of immigrants, language, and domesticated crops and animals. Those factors are examined in excellent detail in Jared Diamond's book, "Germ, Guns and Steel" which I highly recommend for anyone studying the development of world cultures. It's a long read, but well worth it.
