Answer:
12. True
13. False. Correct would be social structure
14. True -> it says most
15. False
Answer:
Philadelphia and Pittsburgh both made good contribute to the evolution in jazz in the twentieth century.
Explanation:
Idk if this is right I just know that New York and Chicago were contributes but aslo Philadelphia and Pittsburgh
if only person was in charge of a government, it would gradually convert into a dictatorship, simply because there are no other branches of the government to keep the executive government in check. This is why governments have three branches, to make sure power is balanced. Two branches and even four branches wouldn't work because of uneven balances in power.
Increase of crops due to new innovations with the farming technique is one that comes to mind, not very sure about other factors though, sorry