It was that "Flat land with poor drainage led to salinization from irrigation waters," that was a factor in the decline of Sumer, since this led to a build up of salt in the soil, which greatly reduced agricultural output.
A "divine right" refers to a right that people people has been passed onto them from God, and cannot be interfered with my laws made by humans. These could include "free speech", freedom from tyranny, etc.
Both poems are complimentary, paying tribute to loved ones.
Why did the south pass Slave codes ?
Since the colonial period, colonies and states had passed laws that discriminated against free Blacks. In the South, these were generally included in "slave codes"; the goal was to reduce the influence of free blacks (particularly after slave rebellions) because of their potential influence on slaves.