People with multiple sclerosis (MS) experience many challenging symptoms. Which statement best explains one cause of these difficulties? Loss of oligodendrocytes in the central nervous system results in absence of the myelin sheath of neuronal axons, impairing rapid saltatory conduction. An increase in the number of oligodendrocytes in the central nervous system results in an overgrowth of the myelin sheath of neuronal axons, resulting in abnormally large action potentials. Damage to ependymal cells results in stagnation of cerebrospinal fluid, damaging neurons. A loss of astrocytes causes leaked neurotransmitters and K+ to accumulate, impairing generation of action potentials.