Final answer:
The main features of feudalism were a hierarchy of social classes and a protection system based on land ownership, with military service and labor exchanged for safety and sustenance.
Step-by-step explanation:
The main features of feudalism during the medieval period included a hierarchy of social classes, a protection system based on land ownership, and a unique economic structure that did not resemble a free-market economy. Unlike a centralized government, power in feudal society was spread among various lords who controlled land and offered protection to those below them in exchange for services. This protection racket was a two-way street: lords provided safety and the means to live for their vassals and serfs, while vassals and serfs provided military service and labor to the lords. Over time, the feudal system weakened due to factors such as depopulation, changing military practices, and the centralization of monarchical power, paving the way for capitalism and industrialization.