The election of Abraham Lincoln in 1860 was the immediate cause of southern resolutions of secession. He was the nominee of the Republican party with an anti-slavery expansion platform, he refused to acknowledge the right to secession, and he would not yield federal property within Southern states.
The gestation period of a human, from time of conception to birth is approximately 9 months (266 days/38 Weeks). 9.5 months is calculated from the first day of the last menstrual period (280 days/40 Weeks).
in a viviparous animal, the period from the fertilization of the ovum until birth. Gestation varies with the species. In humans the average duration is 266 days, or approximately 280 days from the onset of the last menstrual period. A gestation time of less than 37 weeks is regarded as premature; one that continues beyond 42 weeks is considered postmature, regardless of the size of the fetus or other factors. See also pregnancy.