Final answer:
Alcohol and other drugs primarily act on the brain, altering neurotransmitter activity and leading to changes in mood, perception, and behavior. This statement is true.
Step-by-step explanation:
The statement that alcohol and other drugs act primarily on the brain is true. Drugs are chemicals that influence the body's structure or functions, particularly through their effects on the brain. Psychoactive drugs affect the central nervous system by altering nerve impulse transmission. These substances can either be agonists, enhancing neurotransmitter activity, or antagonists, decreasing it.
Substances such as caffeine, alcohol, and certain medications have specific actions on neurotransmitters or receptors, which can lead to changes in mood, thinking, perceptions, and behavior. While some psychoactive drugs are used for medical purposes, others may be abused, potentially leading to addiction and the compulsive use of drugs despite adverse consequences.