a – iii, because the resting potential is the electrical potential difference across the neural membrane.

b – iv, because nerve impulse is an electric wave like response of a neuron to a stimulation.

c – ii, because synaptic cleft is the gap between the pre-synaptic and the post-synaptic neurons

d – i, because neurotransmitters are the chemicals involved in the transmissions of the impulses at synapses.