Question

what are neurotransmitters?
a) electrical signals sent by electrical synapses
b) chemical messengers secreted during chemical synapses
c) the space between presynaptic and postsynaptic cells
d) ion channels in the postsynaptic membrane

Explanation:

Neurotransmitters are chemicals. In chemical synapses, the presynaptic neuron releases neurotransmitters. These neurotransmitters then bind to receptors on the postsynaptic neuron to transmit signals. Option a is about electrical signals (not chemical neurotransmitters). Option c describes the synaptic cleft (the space between neurons, not neurotransmitters). Option d refers to ion channels (not the chemical messengers themselves).

Answer:

B. Chemical messengers secreted during chemical synapses