Answer :
Axons are especially abundant in the white matter in the brain and the white matter in the spinal cord.
What is meant by axon?
A nerve fiber, also known as an axon, is a component of a nerve cell (neuron) that transports nerve impulses away from the cell body. A neuron has one axon, which connects it to other neurons, muscle cells, or gland cells. Some axons can extend all the way from the spinal cord to the toes.
Each neuron in your brain is connected by a single long cable that extends from the cell's main body. This cable is known as an axon, and it transports electrical impulses from the neuron to other neurons. It is hundreds of times thinner than human hair.
As a result, option D, white matter in the brain and white matter in the spinal cord, is the correct answer.
To learn more about axons refer to:
https://brainly.com/question/950620
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