Answer:
chemicals that cross the synaptic gap and bind to receptors on another neuron
found only in the central nervous system (the brain and spinal cord)
Explanation:
Neurotransmitters are defined as the chemicals that is transported from a nerve cell across the synaptic gap to the receptor of another neuron or a target cell such as a gland cell or a muscle cell.
Neurotransmitters are generated in the central nervous system (the brain and spinal cord) and are stored in synaptic vesicles.
"Hence, the correct answer is:
chemicals that cross the synaptic gap and bind to receptors on another neuron
found only in the central nervous system (the brain and spinal cord)".