The nervous tissue or the nervous system is a system in the humans or animals formed by the neurons.
The nervous system can be categorised into two types based on the structure and functions: the peripheral nervous system and the central nervous system.
The central system of neurons comprises of the neurons present in the spinal cord and the brain and the peripheral system which comprises the nerves of the organs present except the brain and the spinal cord like the nerves in the limbs (legs, arms).
Physical change only change the appearances of a substance, not it’s chemical composition. Chemical changes cause an entirely new substance with new chemical formula.
