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

Multiple Choice

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.