Which chemicals are involved in conveying messages between synapses?

The correct answer focuses on the role of neurotransmitters in the nervous system, specifically those chemicals that facilitate communication between neurons at synapses. Serotonin, norepinephrine, epinephrine, dopamine, and tryptamine are all neurotransmitters, which are chemical messengers that transmit signals across synapses from one neuron to another. Each of these neurotransmitters has distinct functions and effects on mood, cognition, and behavior, making them crucial to understanding brain function and development.

In contrast, the other options involve substances that do not function as neurotransmitters. Oxygen and nitrogen are essential gases for cellular metabolism but do not play a direct role in synaptic transmission. Hydrochloric acid and bicarbonate are involved in digestive processes and chemical reactions in the body, but they are not related to neural signaling. Calcium and potassium are important ions that contribute to the electrical activity of neurons and are involved in the release of neurotransmitters at the synapse; however, they themselves are not the chemicals that convey messages between synapses. Thus, option B accurately identifies the key chemicals responsible for communication in the synaptic process.