Yes, it is true that early humans had to endure changes in climate and environment, since things like global warming and cooling, along with major events like the Little Ice Age, meant that the temperatures in the world were changing dramatically.
The correct answer is: C) familiarity with and disdain for the northern industrial workplace.
Secession and, therefore, Civil War were mainly about the right to own slaves. Slaves were, for the Southerns, the most important "material" in the workplace; their region relied on slave-owning in order to do agrarian work.
The Northerns, however, now were in their way to industrialization, where the work at factories was done by employed immigrants and, thus, they were all for abolishing slavery.
