Question

what part of the cell protects and insulates the signal from leaking as it moves along the axon?
myelin sheath
dendrites
nucleus

Explanation:

The myelin sheath is a fatty layer that wraps around axons of neurons, protecting and insulating the electrical - signal (action potential) as it travels along the axon, preventing signal leakage. Dendrites receive signals and the nucleus contains genetic material, neither of which perform insulation of axonal signals.

Answer:

myelin sheath