1 Multiple sclerosis (MS) is a disease that causes demyelination (disruption of the myelin that insulates and protects nerve cells) of spinal nerve and brain cells.  Although the exact case is unknown, multiple sclerosis is considered to be an autoimmune disease.
The skunk is not a rodent. They belong to the family Mephitidae and the order Carnivora which does not include rodentia. They are sometimes placed in the family Mustelidae (weasels) but have been discovered to be less related than was thought.
The balance between survival of prey and predator is part of the reason that our ecosystem is so diverse. The skunk is an example of a prey who uses its chemical defense to scare off predators. The skunk releases a toxin or noxious compound that has a foul smell/odor to it