Question

terminology
clusters of neuron cell bodies and collections of nerve fibers are named differently in the cns and in the pns. for the most part, cell bodies are found in the cns in clusters called (1). this well - protected location within the bony skull or vertebral column is essential to the well - being of the nervous system—remember that neurons do not routinely undergo (2) division after birth. the cell body carries out most of the metabolic functions of a neuron, so if it is damaged, the cell dies and is not replaced. small collections of cell bodies called (3) (gangle - ah, ganglion, singular) are found in a few sites outside the cns in the pns.
bundles of nerve fibers (neuron processes) running through the cns are called (4), whereas in the pns they are called nerves. the terms white matter and gray matter refer respectively to myelinated versus unmyelinated regions of the cns. as a general rule, the white matter consists of dense collections of myelinated fibers (tracts), and gray matter contains mostly (5) fibers and cell bodies.

1 cell 2 ganglia 3 tracts 4 unmyelinated 5 nuclei
1 unmyelinated 2 nuclei 3 cell 4 ganglia 5 tracts
1 nuclei 2 cell 3 ganglia 4 tracts 5 unmyelinated
1 tracts 2 unmyelinated 3 nuclei 4 cell 5 ganglia
1 ganglia 2 tracts 3 unmyelinated 4 nuclei 5 cell

Explanation:

1. In the CNS, cell bodies are in clusters called nuclei.
2. Neurons don't routinely undergo cell division after birth.
3. Small collections of cell bodies outside the CNS in the PNS are ganglia.
4. Bundles of nerve - fibers in the CNS are tracts.
5. Gray matter contains mostly unmyelinated fibers and cell bodies.

Answer:

C. 1 nuclei 2 cell 3 ganglia 4 tracts 5 unmyelinated