When working an occasional night shift, people often feel groggiest in the middle of the night but experience new energy around the time they normally would wake up. This best illustrates the impact ofa. neurogenesis. b. selective attention. c. the circadian rhythm. d. REM rebound.

C. the circadian rhythm.

Explanation: The circadian rhythm refers to a set of natural or physiological processes which an individual experiences within a 24-hour cycle. The circadian rhythm is exemplified in processes such as changes in energy level, when an individual has a weary feeling at night and renewed vigor when awake in the morning. Light-related circadian rhythm is highlighted in the sleepy feeling inherent in animals at night and being awake during the day,thus is the sleep-wake cycle. Other instances of circadian rhythm include changes in body temperature, hormonal release and so on.

answer; obey the closest relative's wishes;