The spinal cord
the skelatal system
In humans, the kidneys are two small organs located near the vertebral column at the small of the back.
Your vertebral column protects the spinal cord. Vertebral column is supported by strong ligaments. Most importantly the muscle tone is there, which act on vertebral column, to protect your spinal cord.
main organ; pancreas is accessory
The main organ of the skeleton is the bones.
the main organ of the muscular system is the muscles
The main organ in the muscular system is the muscles.
None, the only thing running through the vertebral column is the spinal cord which is not an organ
nephridia is the main excretory organ of annelida
The dorsal body cavity consists of the cranial and vertebral cavities, housing the brain and spinal cord.
The Heart is the main organ of a circulatory system.
the heart is part of the circulatory system in the body.