Identify the following as properties of electrical synapses (ES), chemical synapses (CS), or both (B).           

a. ______The plasma membranes of presynaptic and postsynaptic neurons are joined by gap junctions.          

b. ______Transmission is unidirectional and delayed.          

c. ______A presynaptic neuron and a postsynaptic neuron are involved.          

d. ______The use of neurotransmitters packaged into synaptic vesicles is required.          

e. ______Transmission is nearly instantaneous and bidirectional.