Which of the following is a factor that determines the rate of impulse propagation, or conduction velocity, along an axon? a) length of the axonb) the number of axon collaterals extending from a truncated axonc) degree of myelination of the axond) whether the axon is located in the central nervous system or in the peripheral nervous system

c) degree of myelination of the axon

Explanation:

The myelin sheath covers many axons in central nervous system (CNS) ( by oligodendrocytes) and in the peripheral nervous system (PNS) (by Schwann cells). Their function is to insulate axons and to increase the speed at which information travels from one nerve cell to another.

Nerve conduction velocity is specific to each individual and depend on the level to which that axon is myelinated, but also on  an axon's diameter.