"John is 3 years old and always loved playing with balloons. One day John was playing with a red balloon and it popped. The loud noise upset him and he cried. Ever since that day, whenever he sees a red balloon, he starts to cry. In this example, the unconditioned stimulus is ."

Red Balloon

Explanation:

NS= red balloon, UCS= Balloon burst, UCR= crying, CS=Red balloon, CR=crying

CS=CR

red balloon=crying

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