When Dick heard a car backfire, the message was carried from his ears to his central nervous system along:

Circadian rhythms are controlled by the __________

a) pineal gland. b) suprachiasmatic nucleus (SCN). c) thalamus. d) hippocampus.

The hormone melatonin reaches peak levels in the body during the __________

a) morning. b) early evening. c) afternoon. d) night.