Each of the following indicated that the Tang Dynasty had lost the Mandate of Heaven except Question 2 options:

1) invading tribes from the north destroyed Changan

2) severe floods and droughts led to food shortages

3) Li Yuan led a rebellion that overthrew the Sui Dynasty

4) An Shi and his followers gained control of the government

The Dorian invasion is a concept devised by historians of Ancient Greece to explain the replacement of pre-classical dialects and traditions in southern Greece by the ones that prevailed in Classical Greece. The latter were named Dorian by the ancient Greek writers, after the Dorians, the historical population that spoke them.