An axon terminal passes the electrical stimulus to a dendrite of next neuron through ______ reaction
A. Chemical
B. Electrical
C. Mechanical
D. None of the above

Hint: The nerve impulse is passed through a synapse which is the close proximity of the axon of one neuron to the Dendron or cyton of another neuron with a gap of about 200 angstrom in between. In a synapse, the transmitting cell is called the presynaptic cell and the receiving cell is called the postsynaptic cell.

Complete answer: A nerve impulse is a physico-chemical-electrical change in the membrane of a nerve fibre produced by a stimulus at one end and carried along the nerve fibre to its termination without any change in its amplitude.
A series of nerve impulses are transmitted by the nervous system. A wave of negative charge on the surface of an axon marks the position of the action potential at any moment. Action potentials are regulated along the axon. The events that set up the action potential at one spot on the nerve fibre also transmit it along the whole length of the nerve fibre. The changes in the membrane permeability at one site upset the normal membrane permeability at the adjacent area. The action potential then moves to the neighbouring region of the nerve fibre and eventually it covers the whole length of the fibre. Thus the action potential moving along a nerve fibre as a wave is self-propagating, Action potential is propagated along a nerve fibre without any change in its amplitude. It is thus a nondecremental phenomenon.
So, the correct answer is “Option b”.

Note: The vertebrates have evolved a different mechanism for quick conduction of nerve impulses. They have myelinated nerve fibres which carry impulse about 20 times faster than the non-myelinated ones.