Question

Melatonin is a hormone that helps to regulate our sleep-wake cycle. What effect on an individual would living in an environment, which has little to no darkness during summer, have on melatonin secretion?

A. During high light levels, secretion of melatonin would be increased, causing the individual to sleep almost the entire day.
B. During high light levels, the secretion of melatonin would be at low levels, causing the individual to feel more tired throughout the day.
C. During high light levels, secretion of melatonin would be less than normal, causing the individual to feel less tired and have difficulty falling asleep.
D. During high light levels, secretion of melatonin would be at high levels, causing the individual to feel less tired and have difficulty falling asleep.

Answer 1

C. During high light levels, secretion of melatonin would be less than normal, causing the individual to feel less tired and have difficulty falling asleep.

Step-by-step explanation:

Melatonin is the principal hormone implicated in the sleep cycle regulation, and light is the principal factor that regulates melatonin secretion. The duration and amplitude of the melatonin secretion rhythm depend directly on the photoperiod to which the individual is exposed. Melatonin secretion increases from the firsts hours of darkness and extends to the rest of the night, decreasing to its minimum values in the firsts hours of light. In places with little to no darkness at all, melatonin secretion decrese its levels.

Melatonin low levels make the organism feel less tired and more alert and active.