A.
The climate in recorded human history has generally remained stable.
B.
The climate from about 135,000 to 115,000 years ago was in a extremely cold state.
C.
The human race has been lucky to have enjoyed the most favorable period of climate for them to build a socio-economic system.
D.
The evidences scientists collected from the ice cores suggest that a civilization can not have arisen in the period from about 135,000 to 115,000.