We can observe a phenotype whether or not we understand the genetics behind it. In real life, there is a gene called HERC2 that works like I described, and most people with blue eyes have the broken allele of this gene.
Nerves, Neuroglia, and Ganglia. A nerve is a bundle of fibres (axons and/or dendrites) outside the CNS. Neuroglia are cells of the nervous system that help protect and support it. Ganglia are groups of nerve cell bodies lying outside the CNS.
Peripheral nervous system: The portion of the nervous system that is outside the brain and spinal cord. Abbreviated PNS. The nerves in the PNS connect the central nervous system (CNS) to sensory organs, such as the eye and ear, and to other organs of the body, muscles, blood vessels, and glands.The peripheral nerves include the 12 cranial nerves, the spinal nerves and roots, and the autonomic nerves.bbreviated PNS. The nerves in the PNS connect the central nervous system (CNS) to sensory organs, such as the eye and ear, and to other organs of the body, muscles, blood vessels, and glands. The peripheral nerves include the 12 cranial nerves, the spinal nerves and roots, and the autonomic nerves.