Drugs (substances) that affect the central nervous system and alter perception, mood, and behavior are known as psychoactive substances. Psychoactive substances are commonly grouped according to whether they are stimulants, depressants, or hallucinogens. Stimulants initially speed up or activate the central nervous system, whereas depressants slow it down. Hallucinogens have their primary effect on perception, distorting and altering it in a variety of ways including producing hallucinations. These are the substances often called psychedelic (from the Greek word meaning mind-manifesting) because they seemed to radically alter ones state of consciousness.
59. Substance abuse (Line 5, Paragraph 1) is preferable to drug abuse in that ________.
[A] substances can alter our bodily or mental functioning if illegally used
[B] drug abuse is only related to a limited number of drug takers
[C] alcohol and tobacco are as fatal as heroin and cocaine
[D] many substances other than heroin or cocaine can also be poisonous
60. The word pervasive (Line 1, Paragraph 2) might mean ________.
[A] widespread
[B] overwhelming
[C] piercing
[D] fashionable
61. Physical dependence on certain substances results from ________.
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