The Hormone Prolactin Is Found in Different Species, Where It

Multiple Choice

The hormone prolactin is found in different species, where it can have different functions.It is required for osmoregulation in freshwater fish, stimulates nesting in certain birds, and stimulates milk production in female mammals.In developing a hypothesis for how this occurred, the most reasonable assumption to make would be that

A) evolutionary modifications changed the structure of the hormone in different species.
B) the gene for prolactin has arisen independently multiple times.
C) the structure of the hormone is highly conserved, and different responses have evolved.
D) different genes have evolved that produce the same hormone.
E) the receptors for prolactin have arisen independently multiple times.