What part of the human nervous system links the brain to the rest of the body

brain stem connects the brain to the rest of the body through spinal cord

Spinal cord of the human nervous system links the brain to the rest of the body

The spinal cord is the means of communication for impulses from the body to the brain, and from the brain to the body. Without a spinal cord the brain and body couldn't communicate with each other. Spinal nerves carry sensory information like touch, pressure, cold, warmth, pain and other sensations from the skin, muscles, joints and internal organs to the brain via the spinal cord.

93.2 ml + 3920 ml = 4013 ml total  

(93.2 ml) * (2.03 m) / (4013 ml) = 0.0471 m

the volume in in l of the diluted solution would be 0.0471 m.