Hello! I got the answer! So if you look at the word homo and hetero. Homo means the same and hetero means different. So homology is the study of to show the simliarity between organisms. And heterology is the study of to show difference between organisms. This is my first time answering! Anyways have a good day/night!!
The hormone described above is the hormone Melatonin.
Melatonin is a hormone secreted by the pineal gland in the brain, which helps regulate other hormones and maintains the body's circadian rhythm. This rhythm is an internal 24 hour clock that plays a critical role when we fall asleep and when awake. When it is dark the body releases more melatonin.