I need help finding two of the six principles of economics.

Question

The website is: 150 years after fort sumter:why we're still fighting the civil war by Time Magazine
One is called the people respond to incentives in predictable ways.
My answer: " reigning over the study of slavery was Yale's u.b phillips, the son of the salve owners. For decades he was the only scholar to undertake a systematic examination of the plantation economy,which, he argued, was benign and civilizing force for african captives. He concluded that slavery was an unprofitable system that would have soon died out peacefully".
The other principle is the future consequences of choices are the ones that matter
My answer: "slavery was not incidental to America's origins; it was central. There were slaves at jamestown. In the 1600s, writes Yale's David Brion Davis, a towering figure amoung historians, slave labor was far more central to the making of new york than to the making of Virginia. The cotton trade made wall street a global financial force. Slaves built the white house.