Question

what part of the neuron does the number d indicate?
myelin sheath
axon
dendrite
cell body

Explanation:

The myelin sheath is a fatty layer that insulates the axon of a neuron, speeding up the transmission of electrical impulses. In the diagram, the structure labeled D is the myelin sheath. The axon (C) is the long fiber that transmits impulses away from the cell body (B). Dendrites (A) receive signals. The cell body (B) contains the nucleus and organelles.

Answer:

Myelin Sheath