Identify a good that has an upward sloping supply curve. explain your choice

Firms need to sell their extra output at a higher price so that they can pay the higher marginal cost of production. Hence, decisions to supply are largely determined by the marginal cost of production. The supply curve slopes upward, reflecting the higher price needed to cover the higher marginal cost of production.

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.