| 1. | Not enclosed by a Schwann cell and hence not enclosed by a myelin sheath. |
| 2. | Enclosed by a Schwann cell that does not form a myelin sheath. |
| 3. | Not enclosed by a Schwann cell but enclosed by a myelin sheath formed by oligodendrocytes. |
| 4. | Not found in the autonomous and the somatic neural system. |
Assertion : Some areas of the brain and spinal cord look white.
Reason : This is because cell bodies of neurons are situated in those areas.