Question

define nervous system and it's all functions .....

Answer 1

The nervous system is one of two organ systems that maintain internal order within the body. It coordinates the activities of muscles, and organs, receives input from sense organs, triggers reactions, generates learning and understanding, and provides protection from danger. 

functions:-

The primary function of the nervous system is to receive information, and to generate a response to that stimulus. The information and the response could be simple, subtle or complex. 
hope it helps u mark as BRAINLIST

Answer 2

nervous system control coordinate our body it has some specialised cell cold neurone it has a main function to control a body parts
for example if we touch any hot beaker then we suddenly remove our hand due to nervous system this information is send to the Brain by neurone