Forty degrees north, I believe.
Early flooding rivers contributed to the beginning of farming communities because when they flooded, they deposited silt on the riverbanks. This made the land there more arable, or more easily farmed.
The energy supply we have so technology is advancing as the population increases, we need to burn fossil fuels for energy for new technology, causing an increase in greenhouse gases, such as carbon dioxide to be emitted
The country with the smallest population is Vatican City.