riddle - separate with a riddle, as grain from chaff screen sift, sieve, strain - separate by passing through a sieve or other straining device to separate out coarser elements; sift the flour
Causing the Civil War. Historically, textbooks have taught that incompatibility between northern and southern economies caused the Civil War. The industrial revolution in the North, during the first few decades of the 19th century, brought about a machine age economy that relied on wage laborers, not slaves.
The answer to the cause of the war is as large as the war itself. The best way to answer this question is with this statement. The US Civil War was the result of Southern slave states believing that their way of life, slavery, and its economics were becoming marginalized.