Myelin is __.
A. The fatty substance coating axons that speeds the transmission of nerve impulses from neuron to neuron.
B. A long, thick band of nerve fibers that connects the left and right hemispheres of the brain and allows communication between them.
C. The long, threadlike part of a nerve cell along which impulses are conducted from the cell body to other cells.
D. A junction between two nerve cells, consisting of a minute gap across which impulses pass by diffusion of a neurotransmitter.
A. The fatty substance coating axons that speeds the transmission of nerve impulses from neuron to neuron.