Are neurons located only in our brains? and also, when we are in a coma, what happens to our neurons?

the brain is the only place you wil find brain nurons and when a person is in a coma the brain is not running at a fast alert as it would if u where awake the brain is working at a really slow alert speed becuase u wont be able to jus shake and wake a person out of a coma becuase the brains nurons are working slow

sheep is a herbivore animal whereas grasshopper belongs to the class chordates but both of them feed on greens.  

if grasshopper and sheep feeding on a pasture land, i do not think both of them will have any impact on each other. however, the number of the species can make difference. since sheep feed on greens, there is a possibility there left no pasture land for the grasshoppers or they may get extinct.