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.
The average lifespan of a jellyfish is about six to eight months. Jellyfish lifespans typically range from a few hours (in the case of some very small hydromedusae) to several months. Life generally ends after the medusa has begun spawning.Life span varies by species. Most large coastal jellyfish live 2 to 6 months.5-25 days   Two weeks   The average lifespan of an adult housefly is approximately 15 to 25 days.