What did people feel they need in the middle ages due to the absence of the Roman Empire?

Political structure and strong regulations

Explanation:

During the reign of roman empire, many of the smaller regions across Europe followed the rules/regulations imposed by the Roman empire. In exchange for giving their loyalty to the Roman empire, they received protection from Roman soldiers every time criminal activities arise in their community.

After the fell of roman empire, these regions did not really have any laws that they should adhere to.  As a result, many of these regions started to turn into chaos. The people are openly killing/stealing within their communities and there's also another threat from barbarians(outsiders) who saw an opportunity to attack in absence of Roman soldiers.

after the spaniards introduced horses to plains native americans, the lives of the tribes changed. tribes became less settled and sedentary. the horse allowed them to hunt animals such as bison or buffalo, and, instead of staying in one place, tribes began to be nomadic.

estoy bastante seguro de que la respuesta es una