Because he wanted to take away their only way of making a living, by abolishing slavery and freeing their free labor force. Also some Southerners despised Lincoln because the thought he was not tough enough to lead or "Great Country"
The health benefits of Italian diet can be attributed to their natural foods. Vegetables can be attributed to healthy Italian diet, vegetables are arguably the foundation of the Italian diet.
This is all because of how they ate before, they brought this tradition of eat more vegetables than meat.
While you didn't really provide the "following" as the comment above me states, in general, the advantage of secondary sources of primary ones is that they perhaps provide a more objective or even just a broader view on a certain topic. While a primary source of the American civil war would be a letter written by a soldier, a secondary source would be a book that describes more letters taken together and discusses possible information regarding them.
