Answer:
I think its C) Caste System
It began with the fall of the Western Roman Empire and merged into the Renaissance
I beleive the answer would be B: Buring fuel
Bomb shelters and refugee centres, I think
Answer:
The 16th and 17th centuries known as the "incubation period of the modern world" because of the breakthroughs that occurred in the use of water and wind energy for the completion and powering of various industries.
There was also the issue of military revolution which occurred around that time and was the period in which gun powder production started . This led to subsequent production of other weapons during this period.