The fatty substance that insulates and protects the axon is myelin sheath. That is option D.
The nervous system is made up of nerve cells that helps to send and receive signals that are interpreted by the brain.
The parts of the nerve cell include the following:
The axon is part of the nerve cell that transmits electrical signals. it is surrounded by myelin sheath.
The myelin sheath is a fatty layer that insulates the axon and helps it transmit signals over long distances.
Therefore, the fatty substance that insulates and protects the axon is myelin sheath.
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