What are the different types of family

stepfamilies; single-parent families; families headed by two unmarried partners, either of the opposite sex or the same sex; households that include one or more family members from a generation; adoptive families; foster families; and families where children are raised by their grandparents or other relatives.

Explanation:

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.