The reason why you might get tired and sleepy as the sun goes down is because your body is releasing ____ into your bloodstream.

Question

Quizplus · Accepted Answer

Melatonin is a hormone that regulates sleep-wake cycles and is released into the bloodstream when it gets dark outside. This hormone helps to promote relaxation and drowsiness, hence the reason why you might feel tired and sleepy as the sun goes down.

The Reason Why You Might Get Tired and Sleepy as the Sun