There are different types of nerves. Some of them are sensory nerves like the ones in your hands and feet, and some complete other functions. However, they all originate from somewhere.
Cranial nerves originate from the brain itself, and spinal nerves come from the spinal cord. Damaging any can cause serious injury like death and paralysis. There are 12 cranial nerves in the nervous system, and 10 out of 12 originate in the brain stem.
There is a need of attractive force in explaining the existence
of a stable nuclei because there will be a presence of repel in protons to each
other, with that, there is a need to provide another force in which will help
and prevent them from having to fly apart.
Endotherms, such as birds and mammals, use metabolic heat to maintain a stable internal temperature, often one different from the environment. Ectotherms, like lizards and snakes, do not use metabolic heat to maintain their body temperature but take on the temperature of the environment.