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.
Bettas on average live little more than two years, while Goldfish live for decades. Short Lifespans. Killifish are among the aquarium fish with the shortest lifespan. They generally only live a year or two. Bettas are not far behind, averaging only about 2 years. There have been documented cases of Bettas living 5 years or more, but that is not the norm. Livebearing fish such as Mollies, Platy s, and Swordtails, generally live less than 5 years. Long Lifepsans. On the other end of the lifespan spectrum, are Goldfish.
Little is known about how the fish lives, what it eats, how it reproduces, or how many of them are left. The new discovery was based on dissections (pictured) and scans of infant and adult coelacanth samples, as well as 3D reconstructions.he structure is of no use to the living species, which, like all other fish, breathes using gills. Coelacanth fossils have been dated to around 400 million years ago and the species was thought to have died out towards the end of the Mesozoic era, which stretched from 250 to 66 million years ago.