I looked this question up for you and this is what I found I hope it's helpful for you
The answer is the spinal cord starts at the occipital
bone where it passes over the foramen
magnum, and encounters and go in the spinal
canal at the start of the cervical vertebrae. The spinal cord encompasses
down to amid the first and second lumbar
vertebrae where the spinal cord ends.
Oil and water separate because they have different densities.