Final answer:
Neurotransmitters are chemicals stored in neurons that transmit signals across synapses when released; dopamine is a prime example of such a neurotransmitter.
Step-by-step explanation:
Chemicals called neurotransmitters are stored in neurons and released when the cell is stimulated by a signal. The answer to the multiple-choice question is c) Neurotransmitters. These endogenous chemicals are responsible for neurotransmission, transmitting signals across a chemical synapse from one neuron to another target neuron, muscle cell, or gland cell.
One key example of a neurotransmitter is dopamine, which is involved in a number of neurological processes and impacts a wide variety of human behaviors. Neurotransmitters are stored in vesicles within the neuron and released through a process known as exocytosis. Upon stimulation, these vesicles fuse to the cell membrane, releasing their contents into the small gap between neurons called the synapse.