The congress was very powerful at the time and needed to be put in line. The two branches were created to control it. The remaining two branches were not specifically enumerated as thoroughly because they were still weak at the time and their power developed over time.
nationalism, imperialism, militarism , and forming allies
The continental congress was unicameral in nature to avoid disputes with in itself. As a bicameral congress can cause issues inside itself.
Their was a new law made about labor. I'm not sure tho
