Which comparison is correct?
The spinal cord is like a highway, and the nerves are like the roads that branch off the highway.
The spinal cord is like an information center, and the nerves are like the news broadcasts from it.
The spinal cord is like the insulation inside a wall, and the nerves are like the outer shell of the wall.
The spinal cord is like a power generator, and the nerves are like the power lines connected to it.