Concept:Voluntary movement of the legs depends on motor signals travelling from the brain down the spinal cord to the leg muscles.
Explanation:The spinal cord acts as the main communication pathway between the brain and the lower limbs.
When the vertebral column is fractured, the spinal cord is also damaged, disrupting this pathway.
The brain generates the command to lift the legs, but the impulse is blocked at the site of injury.
As a result, the message never reaches the leg muscles, so voluntary raising of the legs becomes impossible.
Sensory signals from the legs may also be affected, but the inability to raise the legs is specifically due to interrupted motor commands from the brain.
Answer:B. impulses from the brain cannot travel to the legs