There is so many reasons but they are complicated to explain
It permitted the expansion of slavery beyond the southern states.
In pre-WW2 Japanese culture, there existed a strict social hierarchy. One of the lowest things one could do in said hierarchy, is surrender. This was seen as dishonorable, and lowered one’s potion to lower than dogs. Any sign of disobedience and hesitation to the captor by the prisoner was seen as disrespectful, and accordingly.
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I'd probably say monolithic domes for 4. They learned how to make a really strong large dome structure that could support a lot of its own weight. I'm not sure for 3 but maybe arches and columns.
Explanation:
