Answer:
Nervous system
Explanation:
Multiple sclerosis -
It is the medical condition , which disables the central nervous system consisting spinal cord and brain .
In this scenario , the immune system attacks the protective sheath , which wraps the nerve fibers .
Due to which , the communication between the nerves is stopped , and the coordination amongst the various organs stops .
There is no proper cure for such medical condition .
Hence , from the given statement of the question ,
The correct term is Nervous system .
