Answer:
Prohibiting slavery in the territories.
Explanation:
According to the ruling it was decided that Congress had exceeded their authority when ratifying the Missouri Compromise, and therefore "had no power to forbid or abolish slavery in the territories west of Missouri and north of latitude 36°30" (Britannica.com).
The answer would be the geography of the country. Its mountain terrain and bodies of water created a boundary to each city-state. Each city-state created their own society. For example, Sparta had created a military society while Athens is the center of many intelligent people. Each city-state also has their worshipped specific gods, Aside from Zeus, Poseidon, and Hades.
The correct answer is Singapore
Singapore is located on the left island of Malaysia at the southern tip as a very small country compared to Malaysia. It is nevertheless an independent parliamentary republic. Although there were some options to unite with Malaysia before through referendums, this didn't happen and Singapore was independent since it stopped being a colony.