Morphine, codeine, and heroin are all opiates that function by

Correct Answer: D

Rationale: Opiates mimic endorphins, binding to opioid receptors to reduce pain and induce euphoria.

Correct Answer: D

Rationale: REM sleep features rapid, irregular EEG patterns similar to wakefulness, reflecting active brain states like dreaming.

Correct Answer: B

Rationale: The cerebellum is the second largest brain region after the cerebrum, located below the occipital lobes, involved in coordination.

Correct Answer: A

Rationale: Myelinated neurons conduct impulses faster via saltatory conduction, where the signal jumps between nodes of Ranvier.

Correct Answer: D

Rationale: Afferent nerves (sensory) carry signals to the CNS; motor nerves (efferent) carry signals from the CNS to effectors.