Here's why:

* Gray matter is a major component of the central nervous system (CNS) consisting primarily of neuronal cell bodies, dendrites, and unmyelinated axons. The nuclei of these neurons are also located within the gray matter.

* White matter, on the other hand, is composed primarily of myelinated axons, which are responsible for transmitting signals between different parts of the brain and spinal cord.

Let me know if you have any other questions!