the infant mortality rate among african americans a. primarily reflects high rates of drug use. b. is similar to the rate among western europeans. c. is similar to the rate among whites. d. is higher than among whites primarily due to biological differences. e. is higher than among whites even if we look only at the middle and upper classes.

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.