This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Physiology
Synaptic conduction is mostly ohodromic because: 
Select and explain. 
A. Dendrities cannot be depolarized, B. Once repolarized, an area cannot be depolarized, C. The strength of antidromic impulse is less, D. Chemical mediator is localised only in the presynaptic terminalThe strength of antidromic impulse is less
D: Chemical mediator is localised only in the presynaptic terminalThe strength of antidromic impulse is less
Answer: D: Chemical mediator is localised only in the presynaptic terminalThe strength of antidromic impulse is less 
Explanation: D i.e. Chemical mediator is located only in the presynaptic terminaOhodromic conduction means conduction in one direction only, from one neuron called the presynaptic neuron to another neuron called the postsynaptic neuronQ.Transmission at synapse is always in one direction only because the neurotransmitter substance responsible for conduction is present in vesicles of presynaptic neurons onlyQ. The post synaptic neuron does not contain any neurotransmitterQ. It has protein molecules embedded in it which serve as receptor for the neurotransmitter.Electrical synapses can transmit signals in either direction.Q