Which of the following make up a social system?
social relationships
political structures
economic system
all of the above

All of the above makes up a social system.

Option D  

Explanation:

Social relationships are important for setting base for any social system. A society as a whole, variety of families, their particular set of rules and regulations all makes up an ongoing social system. Along with this political structures set up rules for a state or a country as a whole, where society structures end, political structures begin. Simultaneously, economic system is totally necessary to make monetary structure running in the country. Economic system keep money moving along the country just like water moves all the way on earth. Thus all three combine to make an effective social system.

1. it was caused by feudalism

2. charlemagne used christianity as a major cornerstone for his rule. cloisters were built all over the empire to act as centers for the (re)population of the vast european wilderness.

3. the europeans feared the next raid every time chetak

i'm not so sure about #6. but i hope i you with the first 3.