Question

Jet lag occurs when a person moves rapidly from one time zone to another, causing conflict between the body's biological rhythm and the new cycle of light and dark. Some scientists suspect that jet lag may result from the disruption of a daily hormone cycle. Which of the following hormones do you think is the most likely suspect?
A. Epinephrine     
B. Insulin
C. Melatonin
D. Estrogen

Answer 1

Hint: Biological rhythms are the natural cycle of change in the body’s chemical products or functions. This is like an internal master “clock” that coordinates the other clocks in your body. The “clock” is in the brain, just above the nerves in which the eyes cross. It is composed of thousands of nerve cells that help sync the body’s functions and actions.
Complete Step-by-step answer:
Jet lag can occur anytime the person crosses two or more time zones. This is due to crossing various time zones putting the internal clock (circadian rhythms), which controls the sleep-wake cycle, out of sync with the time in a new regional setting. For example, if the person leaves New York on a flight at 4 p.m. on Tuesday and arrives in Paris at 7 a.m. Wednesday, the internal clock still thinks it's 1 a.m. That means the person is ready for bed just as Parisians wake up. And because it takes several days for the body to adjust, the sleep-wake cycle, along with most other bodily functions, like hunger and bowel habits, remains out of step with the rest of Paris.
A key impact on the internal clock is sunlight. This is due to the light affecting the regulation of melatonin, a hormone that synchronises cells all over the body.
Epinephrine is in a class of medications known as alpha- and beta-adrenergic agonists (sympathomimetic agents). It acts by relaxing the muscles in the respiratory tract and tightening arteries.
Insulin is a hormone generated by the pancreas that regulates the quantity of glucose in the bloodstream at any moment. It also stores glucose in the fat, liver, and muscles. Finally, it controls the body’s metabolism of fats, carbohydrates, and proteins. 
Estrogens are a group of hormones that play a significant role in normal sexual and reproductive evolution in females. They are also sex hormones. Feminine ovaries make most estrogen hormones, even though the adrenal glands and fat cells also generate small quantities of the hormones.
Therefore the correct answer is Option C.
Note: The hormone melatonin performs a certain role in natural sleep-wake cycle. Natural levels of melatonin in the blood are above average during the night. Some studies have shown that melatonin supplements may be useful in treating sleep problems, like delayed sleep stage, and providing some relief from sleeplessness and jet lag.