Final answer:
Hormones, neurotransmitters, and drugs are types of chemical messengers that play important roles in communication within the body.
Step-by-step explanation:
Hormones, neurotransmitters, and drugs are types of chemical messengers that play important roles in communication within the body. Hormones are chemical messengers released by endocrine glands into the bloodstream to target distant cells or organs. They are typically made up of lipid-derived, amino acid-derived, or peptide structures. Neurotransmitters, on the other hand, are chemical messengers that transmit signals across synapses in the nervous system. They are synthesized and released by neurons to communicate with neighboring cells. Lastly, drugs are chemical substances that can mimic or interfere with the action of hormones or neurotransmitters in the body.