No, slavery was not a part of the reason North Dakota and South Dakota split. North Dakota and South Dakota were part of the Dakota Territory from 1862 until statehood in 1889.
The reasons North Dakota and South Dakota were split had to do with the population centers which, at the time, were several hundred miles apart and with the large size of the territory. There was also the fact that the Republicans wanted two states because that would add to their political power in the US Senate.
There was slavery in the north for the same reason there was slavery in the south, that is to work at labourous jobs.
No, it became a state in 1889 after slavery had ended.
It is an analogy. North Carolina is to South Carolina as North Dakota is to South Dakota.
North Dakota is north of South Dakota.
The US state of North Dakota is north of South Dakota.
North Dakota is up by the border of Canada, Wyoming is just next to South Dakota.
Saskatchewan and Manitoba, Canada are to the north of North Dakota and North Dakota is to the north of South Dakota.
The US state of South Dakota is south of the US state of North Dakota.
North Dakota South Dakota North Carolina South Carolina
The state of North Dakota is north (or above) the state of South Dakota.
The state of South Dakota is south of North Dakota.
North Dakota is bordered by South Dakota to the south.