The hormone prolactin, found in distantly related vertebrates, exerts different effects in different species. From an evolutionary standpoint, this is an indication that prolactin
A) can only have functions related to childbirth.
B) is an ancient hormone whose function diversified through evolution.
C) was a recent evolutionary adaptation.
D) was not required in fish and amphibians.

Question

Quizplus · Accepted Answer

The fact that prolactin exerts different effects in different species suggests that it is an ancient hormone whose function diversified through evolution, rather than a recent adaptation or one only related to childbirth.

The Hormone Prolactin, Found in Distantly Related Vertebrates, Exerts Different