The direct exchange of one set of goods or services for another is _
a barter
b. inheritance
c. tax refund
d. monetary purchase

The answer is actually A, barter. I just took the practice and B was incorrect

first, the romans stayed isolated because they had to defend their own territories from neighboring cities that were harassing them, like the etruscans. second, once the romans managed to defeat their neighbors, and started to expand their territory, they started to build roads and bridges. finally, now that the romans have covered their territory with roads functioning as highways, they could mobilize their legions faster to assemble larger military units in a specific place

i do believe the correct answer is the spread of chinese culture throughout asia and africa.good luck

explanation: