Answer: The correct answer for the blank is- Spinal cords.
Spinal cord ( present within vertebral column) is the part of central nervous system that acts like a nerve center and connects brain to the rest of body parts.
It carries sensory information to the brain in the form of nerve impulses and the motor information ( that is produced by brain) to the respective areas of the body.
By doing so, it links the brain to the rest parts of the body.