posterior root the posterior, or sensory, division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the anterior root to form the nerve before it emerges from the intervertebral foramen; each posterior root bears a spinal ganglion that conveys sensory fibers to the spinal cord.he sensory division of each spinal nerve, attached centrally to the spinal cord and joining peripherally with the ventral root to form the nerve before it emerges from the intervertebral foramen.
Freshwater. Many freshwater fish average about 1 to 3 years of life. Some of the more popular species with this short life span include fantail guppies, swordtail platy, mollies, rainbow fish, hatchet fish, corydoras catfish, some cichlids, rasboras and tiger barbs. There are also several fish that live around 3 to 5 years, with proper care and feeding.
What is the lifespan of a koi fish? While most koi do not reach the exceedingly long life span sometimes attributed to the species, the oldest koi fish lived to be 226 years old. This fish, named Hanako, died on July 7, 1977, according to Mother Nature Network.