Which of the following is correct in case of chemical synapses? I. The membranes of the pre and postsynaptic neurons are separated by a gap called synaptic cleft II. Chemicals called neurotransmitters are involved in the transmission of impulses III. Impulse transmission in chemical synapse is faster than that across an electrical synapse IV. Chemical synapses are rare in our system
a)	I, II and IV	b)	II and III	c)	I and II	d)	I, II, III and IV

(c)

A nerve impulse is transmitted from one neuron to another through junctions called synapses. A synapse is formed by the membranes of a presynaptic neuron and a postsynaptic neuron, which may or may not be separated by a gap called synaptic cleft

There are two types of synapses, i.e., electrical synapses and chemical synapses. At electrical synapses, the membrane of pre- and postsynaptic neurons are in very close proximity. Electrical current can flow directly from one neuron into the other across these synapses

Transmission of an impulse across electrical synapses is very similar to impulse conduction along a single axon. Impulse transmission across an electrical synapse is always faster than the across a chemical synapse. Electrical synapses are rare in our system

At a chemical synapse, the membranes of the pre- and postsynaptic neurons are separated by fluid-filled space called synaptic cleft. Chemicals called neurotransmitters are involved in the transmission of impulses at these synapses